| Lvov 48K (Львов 48K)
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The beginning of cloning The Lvov 48K (Львов 48K) computer was developed between 1985 and 1986 at the Lvov Polytechnic Institute Experimental Research and Development Office (ОКБ Львовского Политехнического Института). The nowadays still operating office bears the NIKI ELVIT (НИКИ ЭЛВИТ) name now. The main contributor to the design was Jurij Dmitrievich Dobush (Юрий Дмитриевич Добуш), who implemented the ULA using discrete elements. He worked together with Evgenij Evgenevich Natopta (Евгений Евгеньевич Натопта), Oleg Vasilevich Starostenko (Олег Васильевич Старостенко) and Vitaly Lev (Виталий Лев). They obtained a significant amount of information from foreign students who resided in the institution's dormitory. The reason for the development was to create a simple computer with good graphics capabilities and a lot of software, which is reliable, compact, and affordable. They chose the ZX Spectrum over the IBM PC, of which they became familiar in the summer of 1984. At the end of 1984, Natopta consulted with colleagues from Kaunas who were also involved in cloning the ZX Spectrum. They agreed to exchange informations, and the idea of commercial distribution also came up. In August 1985, Natopta and Dobush examined a borrowed computer for two hours using an oscilloscope. They were interested in the ULA, and the interaction between the ULA and Z80. Based on the results and the original circuit diagrams obtained from East German students, they began the development. The ROM firmware was typed from a West German magazine. The development was conducted not on paper, but on hardware, with live prototypes. The first version was completed by the end of September (October) 1985. Based on this, the first circuit diagrams were created, carefully considering the replication of the original machine. This was likely a 16K machine, as reports only mentioned testing with games that ran on this type of computer. This prototype was presumably taken to Novosibirsk, to the Novosibirsk Electrotechnical Institute, NETI (Новосибирский электротехнический институт, НЭТИ). Presumably from this was the NETI AiT (НЭТИ АиТ) clone born in 1986 - it is clearly visible that 32K RAM was later added to the 16K model. Although the Kaunas clone designers had a working prototype earlier, they could only complete it after getting the Lvov version's circuit diagrams. However, the Lvov developers copied the 'memory card' from the Kaunas clone. This probably means the extended memory of the 48K model. By the end of 1985, that actual version of the machine was taken to Harkov, and this became the basis of the Harkov 48K (Харьков 48K). They used it as a currency for exchange, as they were already considering the development of an 8086 XT - for which they needed parts and money. After the development was complete, by 1986 the contructors were preparing the mass production. At the end of the winter of 1986, the plans were sent to the Poljaron company. At this time, the lower and upper sides of the PCB were swapped, it seems that was a common practice in the territory of the (ex-)Soviet Union, at least it also happened with the NETI AiT and Zvezda clones. These motherboards produced by the Kulon complex of the Poljaron company bore the inscription 71400HH and were available for purchase in 1987. Starostenko took the documentations to Moscow and St. Petersburg too in 1986. This is also how the Dubna 48K (Дубна 48К) clone was born. The documentations may have leaked out from both the development office and the manufacturing plant, paving the way for further cloning of the clone. As a result of this, the 'second generation' machines without the 71400HH inscription could appear. These machines are called 'two memory fields clones' in the jargon. This means, that the lower 16K RAM of the original ZX Spectrum 48K is provided by eight 2K RU6 memory chips, and the upper half is also provided by eight 8K RU5 chips, half of which are used by the system. Later, of course, the 128K expansion appeared, its creator was A. Jurbev (A. Юрбев). In addition to memory upgrade, it included the replacing of the ROM with 27256 type and installing the AY chip. The essence of RAM expansion is to replace 8 pieces of 2-kilobyte RU6 chips with 8K RU5 ones. [»]
Reconstruction based on old documents The rebirth of the second generation clone (or more precisely the motherboard) was the work of Leonid Cherednik (Леонид Чередник - Leon). In 2017, together with several other clones, he recreated the machine from documents collected by the zx-pk.ru on-line community. The small series production was undertaken by Vitalij Mihalkov (MV1971 aka tetroid) from Novosibirsk. The experimental series in green colour was released at the end of July. This was followed in November by the final version in red. [»], [»] ↑date: 2024/10 |
1986. 
1987. 
1987. 
19??. 
2017/07. 
2017/11. |
NETI AiT (НЭТИ АиТ)
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The first clone in Novosibirsk The Neti AiT (НЭТИ АиТ) from 1986 is the clone of the Novosibirsk Electrotechnical Institute (Новосибирского Электротехнического Института) Automation and Telemechanics department, which is based on the Lvov 48K machine. We have already read about the prototype's arriving in Novosibirsk in the previous session. Considered a successful clone, it provided about 70% of the local clones until the appearance of the smaller and cheaper Leningrad. It was produced in multiple versions, retaining the main design of the initial release. The machine boots with custom firmware displaying the text АиТ НЭТИ. Between the Latin and Russian character sets could be switched with the Move and Erase commands. Three versions were released. The first had a motherboard fixable with 38 wires, directly derived from the prototype. The Kempston joystick controller was placed on a stripboard. The second version was the bug-fixed version, no wiring was needed, memory timings were handled by an RC circuit. The RGB output level could be adjusted via a trimmer. In the third version, the top and bottom sides of the PCB were reversed,, an inverter chain was used for memory timings, and the RGB trimmer was removed. The sequence of DIN connectors soldered to the motherboard: power supply, Kempston joystick, black and white TV, RGB monitor, cassette unit. The BPK Sever and Sever-48/002 machines were developed from the clone. Their circuit diagram is the same, primarily the placement of the components differs on the motherboard. Another difference is, that the blocking capacitors of the RAM chips have separate soldering locations on the newer machines, and the motherboard DIN connectors have been replaced by soldered via wires. [»], [»], [»] The successor of the developer department still functions today. The university is now called Novosibirsk State Technical University (Новосиби́рский госуда́рственный техни́ческий университе́т), and the department operates under the name of Automation (Автоматики) department.
↑date: 2024/11 |
1986. 
19??. 
19??. |
| Harkov 48K (Харьков 48K)
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The Harkov board As already mentioned in the first session, the creators of the Harkov 48K (Харьков 48K) built their machine from one of the unfinished prototype of the The head of development was Nikolai Beljaev (Николай Беляев). Other participants included Miroslav Ivenskij (Мирослав Ивенский), Pavel Grib (Павел Гриб), Artem Terejkovskij (Артем Терейковский), Yura Mendedev (Юра Мендедев), Igor Miloshenko (Игорь Милошенко) and their other friends.
The 30x16 cm motherboard had many bugs and was laborious to set up. The latter is partly due to the large number of microcircuits (68). Once the bugs were corrected, it was a stable clone and quite compatible with the original, Among the 128K extensions, the most well-known comes from Vladimir Mihajlovic Getmanec (Владимир Михайлович Гетманец, VMG, V.M.G., ВМГ, В.М.Г.), who lives in the city, and it dates back to 1990. The schematic, which is almost identical to the Krasnodar 48K, and was released on the same leaflet, not surprisingly resembles the scheme for Lvov 48K: it is based on the replacement of the RU6 memory chips and the ROM.
From from this clone the Ikar-64 (Икар-64) computer was later built.
The reconstruction
The new version of the Harkov board appeared on the virtual market of Zx.pk.com in February 2021. ↑date: 2024/11 |
| Leningrad
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The first mass-clone of the Soviet Union The Leningrad was the first clone which was produced in large quantities and made exclusively from Russian components. Its developer was Sergei Yurevich Zonov. Zonov was graduated from the Bonch-Bruevich St. Petersburg State University of Telecommunications in 1982. With a honorary diploma, he was able to stay in Leningrad and found employment at the now-bankrupt Kozitsky electrical plant. The factory developed military and civilian technologies, and Zonov joined the department dealing with televisions. Later he could work mostly from home. He set up a mini-lab in the kitchen of the accommodation provided by the factory. At the same time, he became a visitor and service provider of the illegal Saturday market near the 'Young Technicians' store on Krasnoputilovskaya Street. Using his own homemade device, he tested electronic components intended for sale at the market. In 1986, he became aware of the ZX Spectrum. He assembled an 'original' ZX Spectrum from a schematic obtained at the market (which was a Harkov 48K schema in my oppionion) and reverse-engineered it down to the last component during troubleshooting. Meanwhile, he eliminated the perceived deficiencies by him, and began optimizing it for mass production. According to an interview in the second issue of ZX Format disk magazine, three main versions were created, differing in the number of chips, which consonant with other sources. From recollections, it emerges that Zonov worked on the clone mostly in the summer holidays, which can explain the two to two and a half years development time. The first version was called Leningrad-0 v1.0 and had 47 chips. In the spring of 1987 were the first mentions of the machine, which appeared on the aforementioned illegal market in the autumn of this year. Only a few dozen units were sold from the machine, which contained about 30 bugs. Zonov removed the labels from the chips. This was followed by a second version, the Leningrad-0 v2.0, which had 44 chips. This version was definitely available for purchase by the end of 1987. The clone is also known as Voenmeh-54M-1 (Военмех-54М-1). This is based on a mistaken hypothesis by Black_Cat from St. Petersburg, which appeared in the SibNews #06 disk magazine. [»] According to the article, the machine is a clone of the Vojenmeh Baltic State Technical University (Балтийский государственный технический университет «Военмех»), which is derived clone from Moscow ('M'), which contained 54 chips ('54'), and it is its first revision ('-1'). The currently well-known Leningrad (1) clone, which uses 41 chips, is based on these earlier versions. It was completed by the summer of 1988. Since Zonov did not have enough financial possibility to start the production, he made an offer to companies. He provided the circuit diagram for free in exchange for 20 blank mainboards, on which he would install his own components and then sell them. Delta-N, Rita, Jaguna, Spektr 48, Ural-48K, Vesta IK-30, Elektronika KR-005, Spectrum Sp 23-24, Kontact, K Spectrum, CICH-48, Sunkar - these are just a few of the brand names under which the first machines appeared, partly from Zonov and partly from other companies. The developer received fewer than 100 circuit boards back, so piracy must had been extensive. Individuals with knowledge of electronics also made such clones. Zonov's company, ZS Research, produced circuit boards labeled as ZX Spectrum 1988 and ZX Spectrum 1989. These clones came to be known in colloquial terms as the 'Zonovski variant', meaning Zonov's version. By the time they became popular outside the city, the name "Leningrad" stuck to them. The price was 130 rubles, roughly equivalent to one month's average salary, which contributed to its widespread adoption. There is no precise data on the number of machines produced; estimates range from 10,000 to 100,000 units. The clone variants developed from the original Leningrads naturally increasing this number. The Leningrad belongs to the category of machines with a 'single-field' memory layout, meaning it is built using only a single type of RU5 chip. Out of the installed 64K RAM, the system used 48K. It also differs from the original Spectrum, that it used simplified port handling. Every even port corresponded to the #FE port, and every odd port to the Kempston joystick port. As a result, it was not fully compatible, but in practice, this did not meant a real problem. The handling of the cassette tape unit's signals has also improved. The non-standard video output became apparent later when the omnivorous Soviet TVs were no longer in use. Fortunately, the modifications, that provide solutions are not too complicated. The 'plus' model is the bug-fixed version from the summer of 1989. Zonov made changes to the board based according on user feedbacks. Similarly to the previous model, he allowed this one to be freely copied also in exchange for 20 circuit boards. The machine was also cloned by a company called Composit, and due to the brand name on the circuit board, this designation remained in public consciousness. The second generation, the Leningrad 2, was developed by unknown developers in Kharkiv. Their work quickly surpassed the predecessor in this area. By the summer of 1991, it was already possible to obtain this machine with higher quality circuit board and documentation. [»], [»], The extremely rare clone outside of this area is an enhanced version with an optional edge connector and integrable DIN sockets on the circuit board. The screen routines are fully ZX Spectrum compatible, and the addressing of the Kempston port is standard, the #FE port remained the same. The electronics responsible for cassette unit have also improved. Shadow RAM has also been implemented: the contents of the ROM could be copied into the empty 16K RAM space. In the 212a laboratory of the number one dormytory of Novosibirsk Institute of Electrical Engineering, a very rare version, the Leningrad Neti 212a machine was also developed based on the first generation Leningrad. It is about 98% compatible with the original Leningrad. The compatibility with the original Spectrums also improved due to standardization of the #FE port handling. The electronics responsible for the operation of the tape I/O also improved here. [»] The use of a new edge connector on the machine introduced another standard, the Neti bus, which was adopted by several other clones - naturally within the city's sphere of influence. The Kempston/Tape connectors are located to the left of the expansion slot, and the Power/RGB connectors are located to the right. Both 48K and 128K versions were produced. In the former, the inscription System 212a CC&K can be seen along with the manufacturing date. The 128K version has the inscription 128K-mini 212A CC&K next to the date. The creators themselves also modded the 48K machines to 128K. The earliest version of the 48K variant found dates back to April 1992, while the oldest known date for the 128K big brother is from december of 1993. [»] A Beta-128 controller was also made for the machine with the Neti bus, manufactured by the Himac company. The combined AY-LPrint III interface is the work of Art East Computers. [»] and [»] A bus splitter was also made in the 212a laboratory. Additionally, there are also known unlabeled, lower quality boards, indicating that this clone was also copied.
The first 128K memory expansion of the classic era was published in the 1991/1 issue of ZX-Revju (ZX-Ревю) magazine by the company Pljus (Плюс) from Moscow [»]
Rebirth on the Internet The story of the first modern clone dates back to spring 2007. Ivan of Kurgan wanted to make a replica of the Leningrad 2, and also to integrate a 128K RAM expansion. Thus the first version of the Leningrad v3 clone was born in the last month of 2007. It contained two bugs, plus it had with non-standard video output. The 128K expansion did not appear, however, the necessary signals for its use are present on the motherboard. The final version, corrected by the author, is Leningrad v3.1, released in April of 2008. [»] The Leningrad v3.1 mod.Zorel 2011 was released after three years with the usual zx-pk.ru community bugfixes. In addition to Alexander Korovnikov from Dnipropetrovsk, who is coordinating, the name of Mikhail Abramov from Moscow (Mdesk) should be highlighted out as the forum member who detected the most errors. [»] About a month and a half later the Leningrad v3.2 mod.Zorel 2011 board came out with corrections and additions on silk-screen printing. [»] In the Russian capital living Aleksanr Zan (who is best known by his Z.A.N. and fan aliases) created a Leningrad 48K clone in October 2010. It was based on two machines from two different manufacturers, built at two different times. He left the factory bugs unchanged, only improved the wiring of the PCB so that it didn't need to be patched with wires. [»] Based on moxjemi's wiring diagrams, Sabirzhanov Vadim Mirzhanovich (aka zst) was made the Leningrad 2010 clone (ZXKit-18) from Chelyabinsk. The design was aimed bugfixing and integrating improvements that simplifies assembly. The wiring thickness has been increased to 0.5 mm and its pattern has been slightly changed. The diameter of the through-holes has been reduced to 0.6 mm on the blue-coloured board. Some additional mini-breadboards have also been added, here the holes are 1 mm. The second ROM chip has disappeared, and the designer has made room for a FlashROM chip instead. The outputs are composite black and white TV and Scart. He kept the machine simple, but collected some useful modding and peripheral wiring instructions. In his opinion, if he integrated anything else, it would no longer be Leningrad. [»] Dobryak from Khmelnitsky, Ukraine, has made his own version of this motherboard. It has a mounting hole in each of the four corners and has a standard floppy power connector. Instead of an amplifier/TV out, the sound was routed out through an integrated speaker. The thickness of the wiring has been reduced to 0.35mm. The sync signal has been integrated into the video signals. The name of the parts have also been silkscreen-printed onto the motherboard. In addition, the usual minor and major bugfixes and changes have been made into the board. Back to zst, the Leningrad 2012 model (ZXKit-20) is also an improvement of the previous design, with better ZX Spectrum compatibility, which was only possible with moddings on the previous version. They can be activated by jumpers. Almost perfect ZX Spectrum and Pentagon compatibility was achieved. The motherboard got the mounting holes, the connectors are placed into a row. They are RCA type for durability, except for the Scart, the 5 volt power supply and the Kempston port which is compatible with the Sega gamepad. The RCA list is: tape in and out, beeper out (this was also integrated on the Scart), black and white composite TV. On the left is an internal IDV-16 connector for the keyboard. Into this, and the pin socket below can be inserted the optional Keyb&Sinc module, which allows the connection of a PS/2 keyboard and Sinclair joystick or Sega gamepad. On the opposite side, there are the pin sockets of VGA&PAL and ULAPlus module on top, and the lower connectors for the 128K+AY and ULAplus expansion modules. There is also reserved space for the latter on the Z-Connector made from the Z80 processor outputs. There is also a vertical and a horizontal ZX-bus on the 19.3x11.3 cm motherboard, which was released in March 2012. [»]
Mikhail Tarasov (Mick, Micklab) from Kaluga started cloning the clone in 2016. The first one was a Leningrad 2 motherboard from November of 2016. [»], [»] On the Leningrad 1 motherboard, restored a year later, he fixed the wiring errors in the original, just like Z.A.N. [»] Last but not least, a Vesta IK-30 clone followed in 2020. The scanned version of the wiring diagram is from Shirokov Roman, aka SysCat, Moscow. Mick converted it to P-CAD 2002, as he did with the previous two motherboards. [»], [»]
The Leningrad Neti resurrection is scheduled for August 2014. That's when Vitaly Mihalkov (aka MV1971 aka tetroid), also from Novosibirsk, launched a replica motherboard reconstructed by Rubtsovsk resident Cat_Alex, which was in public beta and thus contained bugs. [»] and [»]
In July 2015, pavgar, a resident of Rodionovo-Nesvetayskaya, published a list of bugfixes he knew of for the board. [»]
The next step is a further development of this, the128K extended version, which was introduced in May 2015, now fully by MV1971. [»] This was also not bug-free. Most of the bugs on the board were revealed by AHTuXPuCT on the day of publication. The bugs were corrected by gdv2002 on the wiring diagram and sent back to the designer with his own corrections
The project stalled, so gdv took it over. The new board was completed in April 2021. He replaced the RU5 memory chips with RU7, so RAM was expanded to 256K. He made a socket for AY-3-8912 and AY-3-8910 in the empty place of the mainboard. The joystick on the top edge is the DB-9 male, the video is the female version of this, the sound/tape connectors are jacks. The power connector is also a standard DC jack. One of the ROM chips has also disappeared here. [»]
The Leningrad-0 v2.0, the second prototype of the Leningrad was recreated at the latest. The machine, made from a schematic diagram published and restored by the members of the Zx-pk.ru forum, is the work of Roman Boykov (Romych) from Balashikha. Since only the top layer of the PCB could be more or less restored from the schematic diagram, the bottom half had to be completely redrawn. This original, buggy motherboard appeared in mid-October 2022. [»] Thanks to the bugfixes of the forum members vg_alex from Minsk and cmdzod, a bug-free version was born by Christmas. [»] The project has been archived on Romych's GitHub. [»]
New expansions are being created
From Rudny, Kazakhstan p@lex began modding his 1988 Leningrad 48K machine in the mid-2000s. The modifications include expanding the RAM to 1024K according to the Pentagon standard using the #7FFD port, adding four Nemo buses, the 512x192x2 screen mode; a turbo mode developed by himself, and integrating the Gluk RTC. In addition, he implemented Pentagon timing, set the original ZX Spectrum INT value, and supported the use of CGA monitors and modern TVs. [»], [»], [»], [»]
Feliks Knjazev (i.e. SoftFelix) started the implementation of the 1Mbyte SIMM30 RAM expansion for Leningrad 1 in April of 2010. The Saint Petersburg hardwareman was completed his development by the end of the month. Thanks to this, the machine has Pentagon 256/512/1024K compatible memory management. [»]
Mark Haskov (Mirazh) from Penza was released in May 2010 the 256K RAM expansion on Altera CPLD for Leningrad 1. For the implementation of controlling, he chose the programmable logic circuit from the Altera 3000 Max family, which he placed on the breadboard of the motherboard. As for memory expansion, he replaced the 8 pieces of 8K RU5 chips with 32K capacity RU7 ones. [»]
Anatolij Gajvoronskij (Анатолий Гайворонский), also known as Zorel from Dnipro, completed the Pentagon 1024K compatible memory expansion in February 2013 for the Leningrad 1 and 2 machines. Since it is based on an already implemented circuit designed for the Orel BK-08, its main components, the Altera EPM3128ATC100-10 CPLD, the memory module, and the firmware are the same. [»]
As with the other clones, Leningrad was also made to be compatible with the most popular Pentagon 128K 2+ ATM clone for memory and screen routine timings. The initiative is attributed to valerium-labs from Chelyabinsk, who raised the idea on the forum in March 2021. Together with the members, they chose the Altera EPM3032ALC44 CPLD for the implementation. Participating members in the development were IanPo and Serg6845 from Moscow, P321 (Krasnodar) and Oleg Starichenko (solegstar/Harkiv). In addition to the forum, [»] the project -which was completed within the same month- on valerium's GitHub was also archived. [»]
The DIVMMC+RAM128-256+AY interface is a combined DivMMC, 128/256K and AY expansion primarily for Leningrad 1-2 machines from the end of October 2022. You can read about the combi peripheral made by uriskoda at the DivIDE and DivMMC section [↓] The peripheral is presented by FunOldGamer on his YouTube page. [»]
↑date: 2025/01 |
Baltik 48K (Балтик 48K)
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The first clone with extras Baltik 48K (Балтик 48K) is the first ZX Spectrum clone, which offers more extra features than the 48K base machine. It was developed between 1985 and 1987 and was ready by the end of 1987, according to the sources. Presumably it is the work of the staff of the Kaunas University of Technology (Kauno technologijos universitetas) or maybe created by radio amateurs. It was primarily intended for industrial use, and later adapted to a Spectrum clone. This is confirmed by its lot of extra features and details, that increased incompatibility. Over the time, both the firmware and the hardware have been continuously developed. It is belongs to the single field memory machines, the total of 64K made up by 8 pieces of 8K RU5 RAM chips, just as with the Leningrads. From this, 16K can be used as Shadow RAM. The processor operates at the non-standart 4MHz speed. The machine is contains less than 50 microcircuits, and the ULA is emulated by К556РТ4 and К155РЕ3 ROM chips. It also has a parallel I/O port driven by the КР580ВВ55 chip. This was mostly used to control the Kempston joystick and printer. The storage of the firmware is provided by two ROM sockets. It has shadow screen, this is multicolor (8x1) compatible along with the standart one. It does not have a video output in the basic configuration, but this could be installed on the stripboard. The machine is commonly associated the most to the Minsk-based Sonet (Cонет) company. In Rostov-On-Don, the Splav Special Design and Technology Institute (ОКТБ СПЛАВ) also made clones. There are also several technical education institutions such as the Novopolotsk Polychnology Institute (Новополоцкий политехнический институт), and the students of Institute of Radio Engineers of Minsk (Минский радиотехнический институт) also dealt with it. In Grodno, in the mid-90s, an individual also made CP/M and TR-DOS based clones. Generally speaking, from both students and radio amateurs were able to buy machines. Almost all components were available in the Minsk radio amateur market. It was sold in this area till 1995-96. It was about 80% dispersed in the eastern part of Belarus. The first version was released in Moscow's agglomeration in early 1988, but it quickly fading into the background due to the Leningrad and Pentagon machines. The main reason for this was price and reliability. For example, the К556РТ4 and К155РЕ3 ROM chips had to be thermal stress tested. Sonet continuesly ran the machines for two days, which was obviously not the case for amateur assemblies, reducing the reliability of the machines. Besides, burning these ROMs also required a special tool. Sonet was manufactured them in the school building of Yanka Maur street, and the distribution took place on Amur street. The first series was made with a built-in power supply, the second batch with external ones. As for configurations, Baltic was the base clone with a cassette unit. The Baltic+ is the disk version, which was used the self-developed Disk monitor system. Baltic ++ is already compatible with CP/M. Baltic +2 got a printer beside these, Baltic +3 in addition a second floppy drive. Baltic +4 is the two floppy drive version without printer. The mainboards were ordered from the local factory. Beside the finished machines, they also distributed empty motherboards, floppy controller cards, computer cases, flashed ROMs, and CP/M floppies. Of course, here the video circuit has been pre-installed, often leaving out the chip responsible for controlling the parallel port. As for firmwares, the first one is the traditional Spectrum's, only here with bold font. The next one boots with the customized © 1988 BALTIC RUSSIAN text. A turbo loading firmware was also appeared. The line of 'simple' firmwares is closed with the Baltic (c) 1992 SONET v1.2 one. There were several ROM-disc versions containing multiple firmwares. Here you can choose from the menu activated when pressing the NMI button. Two main versions of this are known. One is © 1988 BALTIC RUSSIAN & CPM, which contains CP/M bootloader, copier and assembler. The other is the 1992 turbo firmware, which received a disk formatter and a cassette tester instead of the assembler. There were two subversions of this. The CP/M has 64 character/row screen and used 800K discs. Despite these improvements, CP/M machines have not been widespread thanks to the high price. The Radiojubel ( Радиолюитель ) magazine was regularly featured the machine, with promotional articles and advertising. These are primarily of the writings of the company founder V. Boreysho (В. Борейшо), which were published since the first issue of the magazine, 1991/1. In 1994 or later, Evgenij Stepanovic (Евгений Степанович) and Sergej Anatolevic (Сергей Анатольевич) released a 128K RAM+AY+TR-DOS expansion called BC-1. The description covers the upgrade for the single-field machines, the Baltik 48K, Leningrad 48K and Pentagon 48K. For the two-field ones, it described for the Brest Byte and Santaka clones. This involves soldering RU5 chips on top of the original ones. The AY chip was placed on a separate card. The ROM expansion was optional. The expansion can be used with both 48K and 128K TR-DOS controllers. [»], [»], [»]
The clone served as the basis Т34ВГ1, the КА1515ХМ1-216 integrated circuit. When designing the circuit, this clone was taken basis without its extra functions. This is confirmed by the 4MHz processor speed and the 5: 3 screen ratio instead of 4: 3. The solution of latter, together with the Int signal bugfix, can be found in the document of SPLAV. The machine was the basis of several other clones too. The Kompanon (Компаньон) is the 95% analogue of the Baltik, its ROM-disk is also roughly the same. [»] Of course, clones with minor or greater changes have also appeared, for example the Astra (Астра) [»], the Saulys-1 [»], the Nikos (Никос): [»], the Riga variant: [»], Ural (Урал) [»] és a Raduga. (Радугa) [»] And then we didn't even talk about Т34ВГ1-based clones...
Remake with support topic Leonid Cherednik (Леонид Чередник, i.e. Leon), who was already familiar with the Lvov clone, also made a remake from Baltic . The green test version was released in March 2017, and the final red colour one was also came out in November from Vitaly Mikhalkov from Novosibirsk (MV1971 i.e. tetroid). [»], [»] After the end of the 'official' support, the machine got its own topic. ↑date: 2025/01 |
1987. 
2017/03. 
2017/11. |
| Moskva 48K (Москва 48K)
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The first clone of the Russian capital The Moskva 48K (Москва 48K) clone is associated to Evgeny Pavlovich Fadeev (Евгений Павлович Фадеев) (his callsign is now RV3BJ, then was UV3BJ). The schematic, which was based on the Lvov 48K clone, was given to him by Tadeusz Radusz at the Joint Institute for Atomic Research in Dubna. This version was buggy. Pavlovich and his colleague were worked simultaneously on two prototypes, on which the necessary modifications were made together on the fly. According to wiring diagrams discovered meantime, there were several versions of the Moskva 48K, which differed in the application of bugfixes.
Four remakes were made
The first remake is the work of the Moscow alexey_kw from May 2011. It was created in a single copy based on the original schemas with OrCAD/Allegro design programs, applying all known bugfixes. [»]
Mdesk was also created his own (unpublished) version in P-CAD. He added his own RGB solution, since he could not interpret the original one was in the document. From Kaluga Mihail Tarasov (Mick, Micklab) also draw his own clone in P-CAD 2002. He was taken basis the PCB on the sblive.narod.ru page, with correcting the errors indicated there. [»]
The clone of the already two times mentioned Leonid Cherednik (Леонид Чередник, aka Leon) appeared on the virtual market together with the Baltic remake in March 2017 from Vitaly Mikhalkov(Виталий Михалков, MV1971 i.e. tetroid) ↑date: 2024/10 |
| Krasnodar 48K/128K
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From Moscow to Krasnodar The constructor of Krasnodar 48K, Kijashko Vladimir Anatolevich (Кияшко Владимир Анатольевич) radio amateur (RZ6AT) was on summer vacation in August 1987. At that time, Evgenij Pavlovich Fadeev (Евгений Павлович Фадеев, RV3BJ, then UV3BJ) had already completed the prototype of the Moscow 48K. There was no printed circuit board yet, only a circuit diagram and a working wired device on a breadboard. He took this to Zajcev Juri Nikolaevich (UA6CR) to the city of Krimsk to hold a demonstration for interested radio amateurs. He called his friends, who might be interested in the project. Along with Kijashko (then UA6BIE call sign), Bogdanov Juri Stepanovich (Юрий Степанович Богданов - UA6AP, Timashevsk) was also brought by Kijashko's friend, Juri Pavlovich Bojko (Юрий Павлович Бойко) with car to Krimsk. A fairly large number of interested radio amateurs gathered at the demonstration. The participants were immediately impressed by the machine's excellent capatibilities compared to the Radio 86K. So Kijashko promptly decided to build his own machine. The goal was full compatibility with the demonstrated machine and thus with the original ZX Spectrum. He simplified the video output using a 555ID4 chip (SN74LS155 analog). This left room for the implementation of a parallel port based on the 580BB55 (Intel 8255 clone). The two-layer PCB design was done on Astrolon foil. Three versions were made over three weeks. UA6AP also participated in the assembly and testing. Then the constructor sent the negatives to a radio factory, and by the end of the year, the PCB was ready. Debugging was left for the new year. Later, two other factories were involved in the production of the motherboards. The clone was entered into the 34th Moscow DOSAAF amateur radio exhibition, but unfortunately did not win any awards. However, it was later far surpassed the award-winning works in popularity. Vladimir Mihajlovic Getmanec from Kharkiv (Владимир Михайлович Гетманец, VMG, V.M.G., ВМГ, В.М.Г.) also created the 128K extension for this machine, which is practically identical to the Kharkiv 48K circuit, they were also published on the same sheet in 1990. The main momentum is the replacement of the RU6 memory chips and the ROM - just like in the case of Lvov 48K machine. Although we do not know of an 'official' Krasnodar 128K clone, as no documentation has survived, a clone from the city saw the light in August of 2021. It probably never spread widely due to the rise of the Pentagon 128K +2 ATM. Another reference to the mysterious machine is that the Narcom 128K v1 case bore the inscription Красногорск-128. It is unknown, whether the clone creators at Form Co. Ltd. designed their first machine based on the extension made by VMG, or if the 'planar' type machine mentioned here served as the basis. In any case, the motherboard lacks the 580BB55 chip, the hallmark of Krasnodar, but it is very likely that a daughterboard between the CPU and EPROM simulates its operation. This is supported by the fact that most of the wiring is connected to the expansion bus. [»], [»], [»]
Triple resurrection The first attempt to resurrect the clone can be dated to August 2016. Cat_Alex/QRP from Rubtsovsk reconstructed the circuit diagrams provided by Oleg Starichenko (solegstar - Kharkov; Ukraine) in Sprint Layout. Starichenko was also provided help with it. The project most likely remained unfinished. [»] Then in October 2020, Roman Boykov (romychs) from Balashikha created his own version in EasyEDA. Some changes were made to the circuit, as well as minor developments were introduced, such as the Molex power connector and configuration jumpers. [»] The completed work was also published on his GitHub too. [»] Mihail Tarasov (Mick or Micklab) reconstructed the PCB from Kaluga by the end of February 2021. [»] This replica is a completely faithful true-to-size copy of the original. In addition to the forum, he also shared the results of his work on his vk.com wall. [»] ↑date: 2025/03.
|
1988. 
Krasnodar 128K19??. 
Krasnodar 48K mod.romychs2020. 
Krasnodar 48K mod.Mick2021. |
| LGS-Fregat
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An unfinished Baltik 48K clone The LGS (ЛГС) clone first appeared on the zx-pk.ru forum in February 2015. [»] This was a version with a built-in keyboard. The same version later reappeared on the forum. [»] The production date of the machine is 1990/01 according to the inscriptions. [»] Mihail Tarasov (Mick aka Micklab) found a keyboardless version in the flea market. [»] This included the inscription 29-APR-88 FREGAT and Тул. So the date can be determined precisely, and the abbreviation refers to the city of Tula. The size of the motherboard with keyboard is 22.5х20.7cm, the one without it is 21x14cm. What could this clone have been originally? In all likelihood, a Baltik 48K clone-prototype, on which they tried to integrate the TV/RGB output - as it turned out during Mick's reconstruction unsuccessfully. The suspicion of kinship with the Lithuanian clone is strengthened by the large number of 20-pin ICs, as well as the date of release. The most significant difference between the found two clones is the cassette tape recorder circuit.
Archiválva az utókornak Mick started reconstructing the FREGAT clone in February 2018. [»] However, he got stuck at the video part - not by chance. That's why he started to reverse engineer the another clone at the end of November 2019. [»] This, knowing the above, is not surprisingly, also did not succeed. He archived the results of the work done, but the technical documents are not available on his website, so they have to be searched on the forum. [»] However, the firmwares can be downloaded from the website. [»]
↑date: 2024/11 |
1988/04, 1990/1. |
| Santaka 48K (Сантака 48K)
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The progenitorial Lithuanian clone and its commercial versions The Santaka (Сантака) was the first Lithuanian personal computer, developed by the Department of Computers at the Kaunas Antanas Sniečkus Polytechnic Institute (Kauno Antano Snieckaus politechnikos institutas, now KTU) and the Institute of Radio Measurement Technical Scientific Research (Radijo Matavimo Technikos Mokslinio Tyrimo Institutas). While introducing the Lvov 48K clone, the history of the computer was also touched upon. Thus, the idea for the development arose in late 1984 and proceeded in parallel along the Ukrainian clone, with the parties agreeing to mutual information exchange. Development began in 1985, and a year later the clone was born. Among the ZX clones, it is peculiar, that it has 8 pieces of 2K ROM. The explanation for this is, that at that time there was a shortage of larger capacity ones. The photos show, that often even within a single machine it was not possible to obtain identical components from the 573РФ2 or 573РФ5 EPROMs. Another uniqueness is, that the module responsible for image generation was not integrated into the motherboard, but connects via a separate card. This was also retained for the Baltik 48K successor clone. The lowercase Latin characters were replaced with KOI7 Cyrillic uppercase letters. The machine boots with the inscription SANTAKA KAUNAS-MINSKAS 1986. The connectors on the back panel, starting from the reset button, are: the 5-volt power supply, tape in, tape out, system bus, RGB monitor, composite video output, and finally RF out. In addition to a few prototypes, about 200 units were made with metal housings. Due to unreliable parts and high price, it was never spreas widely. Small-scale production was planned to begin in 1988, according to the Mokslas ir Technika journal. The article reveals that neither large-scale production nor retail distribution in stores was planned. [»], [»] The machine was later made by two 'official' factories as well. Of course, they came with a power supply, cables, machine manuals... and, following ex-Soviet tradition, a factory cassette. The bottom of the machines also features a triple RGB trimmer and the speaker's potentiometer. Whether these were also present on the original Santaka, can only be speculated. The clones were first mass-produced by the Krasnodar Measuring Instruments Factory (Краснодарский завод измеретельных приборов) under the names Impuls and Impulse-M (Импульс and Импульс M). The latter included a built-in joytick adapter and a more advanced Secam/RGB module connected to the motherboard. The joy connector replaced the tape-in connector, and the tape-out connector was replaced by a combined Tape I/O. The machines were booted with the inscriptions 1989 ИМПУЛЬС Краснодар and ИМПУЛЬС-М Краснодар'91. The manufacturing company was privatized in August 1993, and according to the clone's serial numbering, this period leading to bankruptcy ended production. In terms of prices, the Impulse was 995 rubles in 1990, which rose to 1098 the following year. In 1990, the Minsk V. I. Lenin Minsk Instrument-Making Plant (В.И. Ленин Минское производственное объединение) started production under the name Santaka-002 (Сантака-002). In 1992, the plant changed its name to the Belarusian Production Association of Radio Engineering "BELVAR" (Белорусское производственное объединение радиотехники «БЕЛВАР»). The new name also appeared on the documentations provided with the machine. The metal housing of the original Santaka/Impulse pair has been replaced with plastic. The composite and RF connectors were often covered by a perforable blind cover. In 1991, the price was 1500 rubles.
↑date: 2025/04 |
több kép
1986. 
több kép
1990. 
több kép
1992. 
több kép
1990. | |||||||||||||||||||||||||
| Moskva 128K (Москва 128K)
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The forerunner of Pentagon 128K The Moskva 128K (Москва-128) was the first 128K Soviet clone. It can be considered the predecessor of the Pentagon 128K 2+ ATM, it is essentially a Pentagon without a Beta-128 controller. It was created by the ATM association. The abbreviation initially stood for the Moscow-based Associaciya Tvorcheskoy Molodezhi (Ассоциация творческой молодёжи), meaning the Association of Creative Youth. Later changed to the Association for Technics and Microelectronics (Ассоциация техники и микроэлектроники) name, keeping the already introduced abbreviation. The relationship between the Moskva 128K and the Pentagon 128K ATM is evidenced not only by the similarity of the specifications and the circuit diagram, but also by the fact that the circuit diagrams were obviously made by the same person. [»] és [»] The machine was released in 1989. The 128K RAM is realized with 2x8 pieces of 565РУ5 (ТММ4164) chips, each having 8 Kbyte capacity. It included a ZX-Lprint III interface and a Centronics port. The image can be obtained through an RGB connector adjustable with trimmers, or on a black/white composite TV output. The 537РУ10 (HM6516-9) or 537РУ8 (TC5516) 2K RAM chips were responsible for the double Sinclair joystick emulation, as well as for the five programmable buttons. Of course, the cassette unit input and output can also be found on the motherboard. The power supply is 5 volts, the system connector has 2.5 millimeters pin spacing. The main firmware is stored in the 32K 573РФ7 or 573РФ8 EPROM (27256 analog). The printer firmware was located in the 2K 573РФ2, which is equivalent to the 27216. It was made in several subversions, the motherboard contained two to four errors. It was difficult to install, among other things, this is why it was not popular. Although - according to the circuit diagram- the creators wanted to make a ZX Spectrum 128K+2 compatible machine, the slightly faster, and thus incompatible, Pentagon standard was born, which later became the de facto standard in the territory of the former Soviet Union.
Quadruple attempt for recreating Firstly, moxjemi from Krasnoyarsk made the Sprint Layout version of the motherboard. After the bugfix by Abramov Mihail (Абрамов Михаил, aka Mdesk), the final version was completed by October 2011. [»] The fully functional remake of the motherboard is again associated with the Moscow-based Leonid Cherednik (Леонид Чередник - Leon). The first public version, v1.1, was released in green color in June 2017. [»] The bugfixed v2.22 red board, along with the Lvov 48K and Baltic 48K boards, appeared in the Zx-pk.com virtual flea market in November. [»] The creator of the green and red motherboards is again Vitalij Mihalkov (Виталий Михалков, MV1971 aka tetroid) who lives in Novosibirsk. The Zx-pk.ru forum members started their own online support forum for the remake. [»] Leon's official support page has disappeared in this case as well. Mihail Tarasov (Михаил Тарасов, Mick, Micklab) from Kaluga released the P-CAD 2002 circuit diagram of the motherboard in August 2020. However, this project unfortunately remained unfinished. [»] In mid-November 2024, Roman Boykov (Romych) from Balashikha created his own bug-fixed schematic diagram of the Moskva 128K motherboard based on the documents from the Zx-pk.ru forum (although the motherboard was not completed, so testing did not take place). The system bus connector became a standard 2.54 mm pitch. Other components were also replaced with modern equivalents. In addition, the components and connectors on the motherboard were labeled. [»]
↑date: 2025/02 |
1989. 
2017/07. 
2017/11. |
| Taganrog 128K/48K (Таганрог 128K/48K)
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Three-tiered Leningrad clone The Taganrog 128K/48K (Таганрог 128K/48K) computers were developed between 1989-91 within the framework of the Taganrog Institute of Radio Engineering (Таганрогского радиотехнического института). Into the development was involved the Department of Antennas and Radio Repeater Devices (кафедре Антенн и радиопередающих) and the MIUS Research and Design Office for Modeling and Control Systems (Научно-конструкторское бюро моделирующих и управляющих систем МИУС). The list of students of the Radio Engineering Faculty who participated in the development: Andrej Vadimovich (Андрей Вадимович), Sergej Magomedovich Alhasov (Сергей Магомедович Алхасов), Viktor Vasilevich Kozhenjakin (Виктор Васильевич Коженякин) and Vitalij Mihajlovich Majsov (Виталий Михайлович Майсов). In the first half of the 90s, it was the most popular clone in the Rostov region. This was due, among other things, to its small size, 128K RAM and Kempston port, as well as the expansion connector, in addition to the affordable price. The 24.9×14.3 cm motherboard is based on the modified scheme of the Leningrad 1. One of the few clones - besides Profi and Elara 128K v1.0 - with a modular design. So for the main motherboard, the manufacturer himself offered (combined) additional boards. The vertically oriented bus was able to achieve a compact sandwich structure, so it could be installed into most computer cases. It could also be installed in a microcomputer case using only the motherboard (and possibly an AY card). Any ZX-standard expansion card can be connected to the system bus. In the spirit of the previously mentioned modular structure, developers offered several own cards, that could be connected sequentially. One of the combo card features a floppy disk drive controller with serial and parallel ports. The other is the EPROM flasher card. There was also a board for handling the extended keyboard and also a schematic for the AY interface. A keyboard and AY combo-card were also introduced. The boards were assembled by hand. 'Of course' there was appared a pirated version with TS7M logo with a slightly modified circuit. The pirates not only copied the machine, but also did not hesitate to use the documentation for their own clone. The machines could also be purchased as kits, for example, from Recly Computer Company. [»] The first DIN connector of the motherboard is for the 5 volt power supply. It's followed by the system bus. The Kempston joystick, tape recorder and RGB are closing the line. The motherboard is relatively freely configurable. In the ZX128/64 configuration, the required 32K ROM size may consist of 1 pieces of 27256 (compatible) EPROM or 2 or 4 27128, 2764 types. Since there are only two sockets, a pigback solution should be used in the latter case. The 64K RAM requires 8 RU5 chips. The 128k config requires 16 RU5 or 8 RU7. ZX48 requires a simple 27256 or double 27128 EPROMs, and eight RU5 for RAM chips. The EPROM burner card is dated to 1990. The burner program is the work of Alhasov Sergei (Алхасов Сергеи, Friendly Software) from MIUS. The hardware is compatible with the 2716, 2732, 2764, 27256, 27512, 573РФ2 and 573РФ5 (analogs of 2716), 573РФ4 and 573РФ6 (2764) EPROM chips . Burning the largest capacity 27512 is done in two steps, and of course is not possible with 48K machines. The disk drive and Centronics-RS-232 interface expansion was released in 1991, according to the documentation. The LPrint III compatible interface is uses the TR-DOS version 5.03. The circuit responsible for handling the expanded keyboard appeared in the same year. This, in addition to the 8x5, also supports 8x6 and 8x7 keyboard matrixes. The functions of the additional keys are stored in the 573РФ2 or 573РФ5 EPROM. The AY interface is compatible with the AY-3-8910/YM2149F type. The (Flash)ROM/RAM disk comes from the Coders' Academy hardware guy Aguzov Igor Viktorovic (Агузов Игорь Викторович, aka RZ Soft). The version number of the found software is 6.19 from 1996. [»] In the May 1997 issue of Public Spirit, the team's first and last only issue of this diskmag, already the version 6.20 is listed. [»] The size of the ROM disk is 512K, the RAM disk is 2048K. An interview with Sergei Magomedovich Alhasov revealed, that they were approached with the idea of a slot machine based on the Taganrog 128/48, hence the start of development. [»] The final product included utilities and game programs. In Rostov-on-Don, the Omega Hackers Group launched the DonNews discmag, which was published with 21 issues from January 1999 to March 2005. In Rostov-on-Don Omega Hackers Group was started the DonNews disc magazine, which was published with 21 issues from January 1999 to March 2005. In issue 12, we can read from Andrej Petrovic Gorelov (Андрей Петрович Горелов, Disabler) about modding Spectrum clones to Pentagon 128K 2+ compatibility. [»] As a local machine, the T-128 naturally received a separate article in this September 2000 issue. [»] In issue 17 (late April 2002), Disabler also published the schematic of the 32/64... 256K cache expansion (for Spectrum, this means shadowRAM) [»] Igor Semenov (Игорь Семёнов, Steve of Coders' Academy) has made the 1024K RAM expansion for the machine, which is compatible with ATM Turbo, Pentagon and Profi standards. You can read about the expansion in [»] Deja Vu 9 (November 1999) and Polese 16 (February 2000). [»] We can also find ideas for implementing a bank LED map in the issue of Inferno diskmag 2, written by Maksim Saskin (Максим Шашкин, Shaitan). [»] The article, published in March 2001, also covers the Scorpion and Spark machines.
Reconstruction attempts In late October 2022, gdv2002 from Kurgan was created the schematic diagram of the motherboard in Sprint Layout. There was also a plan for a DeepTrace version, where one of the EPROMs would be replaced by the AY chip, but this project was also left unfinished. [»] In 2024, a three-slot ZX-Bus compatible splitter card was released. Minimal modding is required on the motherboard, and also on the card, as it is not completely bug-free. [»]
↑date: 2025/03 |
1989. 
19??. 
2024. | |||||||||||||||||
Pentagon
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The Pentagon story of the 1990s The Pentagons were the most widespread ZX Spectrum clones in the successor states of the former Soviet Union in the 1990s. Their prevalence was due to their free access to documents and their easy, even homemade possible construction. They were also relatively easy to expand, so such upgrades released to them, which counting extreme in the world of 8-bit microcomputers. Among other things, processor tunings, memory expansions, sound cards, hard disk and real-time clock interfaces, new screen modes, etc., which have been introduced mainly into to crackers’, hackers’, developers’, swappers’ machines. The default configuration soon became the Pentagon 128K with an integrated 640 KByte Beta-128 disk drive and LPrint III interfaces. It was popular also with optinonal 3-channel AY or YM audio chip, possibly enhanced with Covox variants and a Kempston mouse. For the most popular model, the Pentagon 128K 2+ ATM (see later), the timing of memory and screen routines differed from the original ZX Spectrum 128K. After being considered the most common machine, this timing has become standard in both demos and games in the former Soviet Union. So programs that are sensitive to this, will not run perfectly on other clones that are compatible with Spectrum timing and, of course, nor on the original Spectrum machines. Better programs helped with this by using setup. Later, software with automatic machine detection and those that achieved compatibility with timing-insensitive encoding were appeared. Owners of other machines have often used switch-activated modding for the desired effect. Because they were circulated as circuit diagrams, the appearance of each Pentagon machine may have varied greatly. Some of them were reminiscent of a traditional 8-bit microcomputer, and were also ones mounted in a desktop or tower case. Their processors were first imported Z80A, B and H and clones, respectively. Then became the domestically produced but GDR Z80 clone, the U880 CPU variants, the Т34ВМ1, КP1858ВМ1/BМ3 and КM1858ВМ1/BМ3. Processors BM1 are based on NMOS and BM3 on CMOS. The latter is the rarest for Spectrums. KP and KM are referring to plastic and ceramic enclosures, respectively. In the cavalcade of different versions and moddings, it's impossible to keep track of the numbering and exact release dates of each version. However, by combining the certain and uncertain points, we can get a relatively accurate picture of the evolution of these machines. The starting point is the Pentagon 48K clone with Beta-128 disk- and КР580ВВ55A-based three channel parallel interface. Then it was continuously expanded with modules that were no longer high-tech at the time, but could be produced with relatively cheap and simple technology. These include the 128K RAM expansion, the AY/YM chip, Kempston joystick interface, and more or less bug fixes and expansions for Beta-128. While describing and documenting the story, a somewhat arbitrary standardization of nomenclature is also inevitable. My own names will be in italics and bold, and the machine names in the documentations and sources will be in normal type. The very first machine, the Pentagon 48K, was born in 1989 in Moscow. Its constructor is Vladimir Drozdov (Владимир Дроздов), a well-known radio amateur who died in February 2017. Logically following the sources and dates, clone production initially took place at the Zvezda factory (which until 1991 was called Zagorskij Elektromehaniceskij Zavod – ZEMZ) in the city of Sergiev Posad (formerly known as Zagorsk). Let's review the chronology of events and the origin of naming. So Drozdov first designed the machine. Then ZEMZ's electrotechnical department (Agat-9), which was left without a state order, started preparing the production. (The color of the motherboard and the PCB wiring are clearly reminiscent of Agat computers.) Since all the clones that had appeared up to that point had brand names, it was necessary to find one for the new machine as well. The name Pentagon was first used by hardware specialist Rozhkov Roman Anatolevic (Рожков Роман Анатольевич) in the summer of 1989. According to him, the "ancestor clone" on which the machine is based was developed at the headquarters of the Russian Ministry of Defense (i.e. in the "Russian Pentagon") or at one of its research institutes from the Lvov 48K clone, and Drozdov developed it on this basis. Another possible origin of the Pentagon name, is that the external wiring forms a regular pentagon on the computer side of the back of the motherboard. Konstantin Viktorovic Sviridov (Константин Викторович Свиридов, aka Conan) explained this version of the name origin in the August 1992 issue of Radio Amateur magazine. At the same time, he knew Rozhkov personally (they also worked together for a short time assembling various ZX clones) and therefore interesting that he did not mention the former version of the naming origin in the newspaper. In any case, in the age of the Internet, he already came up with this version too. The clone was brought to the Moscow market by Sergei Sismincev (Сергей Шишминцев) with his friends, who were an employee of Zagorskogo optiko-mehaniceskogo zavod (Загорского оптико-механического завод), another company operating in the city of Posad. They used the nickname Sparka (Спарка - a computer paired with disk controller). Meanwhile, the designer created a 128K RAM expansion. Since the Pentagon 48K was produced in small series, two enterprising youngsters, 'Dima' and 'Vologya', began to produce them under the designation Z01.90. [»], [»] The circuit diagram of these motherboards is slightly different from the original. [»] When the Pentagon 48K was ran out of production, the manufacturing company further developed the clone under the name Zvezda (Звезда) and produced it from 1991 to 1994, changing the machines every year. Their common feature, is that they are connected to the machine cases with a docking card, and that the components of the Beta-128 part are not soldered in most cases (although there is also such a version). The first version, released in 1991, was installed into the Agat keyboard, where the coverplate was adapted for the Zvezda keyboard. This was followed by Zvezda-001 in 1992. The numberless Zvezda was released in 1993. In the last year of production, the 1994 model was designated Zvezda-01. As for the chassis, the raised chassis of the Vector-06Ts computer was used here for the first time. Then the company built a very similar case of its own. The first version of it is dark gray, the second has a light color. In addition to the motherboard and dock-card, a full-fledged speaker was installed in these housings. The connectors are joystick, power supply, tape recorder, black and white, color TV and optional disc drive. Starting in 1993, the top and bottom PCBs of the Pentagon 48K motherboard were reversed. This motherboard is darker - this is probably when they ran out of raw materials intended for Agats. The two motherboards are somewhat incompatible with each other. The keyboard has 52 buttons, where the plus keys have functions that can be accessed originally by pressing two keys together (for example, Del=Caps shift+0). Keyboards of 1992 had stickers, another years have concave, painted type. The first ROM version is 4.91. This one was supported the Cyrillic characters, but the later 1992 one already not. About 200 sets were produced, with high quality compared to ex-Soviet clones, without warranty problems. [»], [»] Underneath, the Pentagon 128K was created in 1989 by unifying the Moscow 128K motherboard, the Pentagon 48K's Beta-128 interface, and the optional AY/YM card. It was likely never produced in large quantities, and photo documentation is also nearly missing, only a single image-series available on the zx-pk.ru forum. [»] Its creator is the ATM company in Moscow. The abbreviation covered firstly the name Associaciya Tvorcheskoy Molodezhi (Ассоциация творческой молодёжи), ie Association of Creative Youth in Moscow and then changed to the Association for Technics and Microelectronics (Ассоциация техники и микроэлектроники), retaining the abbreviation already introduced. MikroArt also consisted of a similar team of young people in the capital dedicated to technology and science. They have been an independent company in the field of mechanical engineering and technical publishing since April 1992 and have been operating ever since. In the production of Pentagons, the likewise Moscow-based Solon, along with the affiliated GrandRoMax (GRM) from Fryazino was also actively participated. Solon was a very universal IT company: distributing software, publishing literature, hardware developments: they were all part of his profile. They are still operating as a publishing company called Solon-Press. The official name of the partner company is GrandRomMax Independent Science-Manufacturing Laboratory of Computer Techniques, so the company has apostrophized itself as an independent computer research and manufacturing institute. Clarifying the names of the various 128K Pentagons is impossible even by reading contemporary textbooks, documentation, journals, and diskmags. After all, even the same machine called differently in the individual advertisements and documentation, not to mention the confusion created by the common language and the pirated versions. As there is no more transparent solution, it is worth dividing the 128K Pentagons into generations based on the analogy of the ZX Spectrum 128K, 128K+2 and 128K+3, supplemented by the name of the developer. The manufacturers also seem to have thought of something like this, even the names are similar - though they have not applied it at all consistently. For the years of launch, I took into account the first known advertisement used by the manufacturer and the year of the technical documentation. Where the year of manufacture and distribution may have fallen to the following year, I will also indicate it. So. The already mentioned first generation 128K model (1989) is named to Pentagon 128K according to the outlined nomenclature. The second generation, the Pentagon 128K 2+, is an advancement of the previous model, incorporating the Beta-128 interface, along with its bug fixes, modifications, and optimization of the mainboard for mass production. (ATM ad: November 1990, distribution 1991). The third generation, the Pentagon 128K 3+, has an integrated AY/YM and joystick interface (ATM: start of production unknown, but were certainly sold in 1994; [»] Solon documentation, GRM motherboard: 1993). Substantial hardware developments also came to end here with the advent of PC clones and the deepening recession of the ex-Soviet economy. The last, the fourth generation of the Pentagon 128K 4+ means only reduced-size motherboards (Solon advertisment and GrandRomMax documentation: both in 1994). In light of all this, the detailed evolution is probably to look like the following after the first-generation machine came out. The most widely used clone has become ATM’s and MikroArt’s machine - as described at the beginning of this chapter. So this second-generation machine was launched in November 1990, taking account its popular names as Pentagon 128K 2+ ATM, the Pentagon 128K ++ ATM, the ATM-128K, Pentagon 128K/91 and ATM 1991 and the company's advertising habits, wide distribution could begin in 1991. Presumably, a smaller series already was appeared on the market by Christmas 1990. A horizontal blank line can be clearly seen on the PCB, which will play a role in the next series. Beside the motherboard they also created their own AY-YM adapter card. This card must be inserted into the socket on the Z80 processor and contains the Z80 as well as the AY chip (all signals required for the sound chip control are on the Z80 socket). Two modifications of the second generation ATM motherboard are known: the Pentagon 128K 2+ ATM Z1992 and the Pentagon 128K 2+ ATM Z1994. More than likely, it's the work of the duo mentioned at the 48K little bro. The Pentagon 128K 2+ KIS is the second generation clone of the Kievskie Informacionnye Sistemy (Kиевские Информационные Cистемы) from 1994. The computer’s floppy drive has a built-in power supply, which provides power to the machine itself. The label ‘720K’ suggests that the system is compatible not only with TR-DOS but also with IS-DOS.
The third generation’s name for ATM is also Pentagon 128K 2+ ATM, but it is also known as Pentagon 128K 2.1, although its name is logically would be a Pentagon 128K 3+ ATM. Here, the AY chip and Kempston controller were integrated into the horizontal blank space of the previous motherboard. The sound chip operates at the non-standard 3.5MHz frequency. The use of a cassette recorder is no longer supported. The ZX Lprint III interface connector is also missing, but the controller ROM slot is still on the motherboard. In case of Solon, addition to Internet resources, we can best rely on Solon's own user manual if want to dig deeper into the subject. It bears the title of ZX Spectrum 128K with noble simplicity and was released in 1994. What is certain is that the screen and memory timing compatibility issues have been fixed to be compatible with the original ZX Spectrum. However, this is exactly why they lost, as by then ATM timing had become the standard. Their entry model was called the Pentagon 128K. It does not include the AY/joystick part, but they can be soldered to the breadboard on the right side of the motherboard. The company itself has also offered such mini circuits. After all this, feel free to christen the model the Pentagon 128K 2+ Solon. Apart from the book ad and some forum comments, you can't find any reference to the machine or its accessories … The names of the Pentagon 128K 3+ Solon are shown even more chaotic than before: it is known by the names of Pentagon 128K 2+ Solon, Pentagon 128K ++ Solon, Pentagon 1993, Pentagon-128 03, Pentagon-128K 1993g. This motherboard is labeled PS.03 and is listed as Pentagon-128 03 in Solon's partner, Mikronix's advert in the book. The Pentagon-128K 1993g inscription is on the motherboard documentation. The size of the board is the same as the ATM 2+’s dimensions, Solon also refers to it as a Pentagon 128K 2+ machine modified by them. Being as a third generation, the stereo AY circuit has been integrated here as well, and the joy interface already supports the Sinclair standard in addition to Kempston. We can connect both TV and monitor. DIN connectors are already on the motherboard. Thus, a pre-perforated aluminum connection plate must be fitted to the rear of the enclosures. A variant of the Beta-128 interface, the Beta Turbo can handle two drives here. The firmware comes here from the Profi clone (October 1990), which provides double speed of positioning, reading, and formatting, with writing remaining at standard speeds. The power supply to the circuit has also been improved. This Beta-Turbo version is notoriously buggy by factory. If you write to a disc written on a turbo machine with a non-turbo machine, the contents of the disc will be destroyed. The final bugfixes appeared in issues 12 (March 1995: Vladimir Larkov) and 14 (August 1995: Kirill Gromov) of the Spectrophone diskmag. The point is, that the write speed should be set to normal before starting write operations, not during it. The Estonian equivalent of the Pentagon 128K 3+ Solon is the Sprais-128. It is the product of Gag Ltd. from Tallinn, the inscription on the motherboard is (C) 1993 DECA. Very probably was produced in a small number of series. [»] In the book mentioned above, there is already an advertisement of a mini-tower case with the inscription ‘Spectrum 128.’ In reality, the fourth-generation PS-04 motherboard received a similar case, but it bears the Solon ZX Spectrum inscription. This is not a typo, one motherboard uses a dot, while the other uses a hyphen to connect the type and generation designations. So even here, they haven’t reached consistent type labeling… Based on the previous information, we can call the Pentagon 128K 4+ Solon either ‘Pentagon-128 04’ or, according to the teaser in the mentioned publication, ‘Pentagon-128K 1994g.’ The shape of the board has changed dramatically, but the tangle of wires around the Beta-Turbo suggests the bug fix mentioned earlier. The RU5 RAM chips were replaced by 8 pieces of 32K RU7, theoretically providing a total of 256K. However, in the factory configuration, the system only recognizes 128K. Presumably, due to the better reliability, power consumption, and cost of the memory chips were built into these bigger capacity modules. From here, it’s just a little modding needed from Steel Drugon, and the 256K Pentagon is ready. [»] The GRM partnercompany have been redesigned the third and fourth generation machines since 1993. The DIN connectors integrated into the motherboard and the metal cover plates remain, the size of the board has of course been reduced. Their first machine started its career as GrandRoMax 1. The board shows the 128K (1993g) inscription, so this is the Pentagon 128K 3+ GRM. It has become known as either GRM (1) or GRM-1. The GrandRomMax Grandboard 2+ and the GrandRomMax Grandtower 2+ are two versions of the Pentagon 128K 4+ GRM. The first machine was marketed in the traditional 8-bit configuration, and the second as a mini-tower. They were built on a new, even narrower motherboard called GRM2+. The motherboard known in three public versions: v4: 1994, v5: 1995 and v8: 1996. The machine took advantage of the full 64K ROM, with the 'Magic' button you can call the built-in Service Monitor, which is placed in the originally empty ROM-part of the Pentagons. Unfortunately, these machines inherited the Beta-Turbo bug, which they tried to fix with the aforementioned fixes.
In 1994 or later, Evgenij Stepanovic (Евгений Степанович) and Sergej Anatolevic (Сергей Анатольевич) released a 128K RAM+AY+TR-DOS expansion called BC-1. The description covers the upgrade for the single-field machines, the Pentagon 48K, Baltik 48K and Leningrad 48K. For the two-field ones, it described for the Brest Byte and Santaka clones. This involves soldering RU5 chips on top of the original ones. The AY chip was placed on a separate card. The ROM expansion was optional. The expansion can be used with both 48K and 128K TR-DOS controllers. [»], [»], [»]
Among VMG's Pentagon 128K enhancements, the 512K RAM expansion, one of the implementations of 7MHz turbo CPU mode, the application of ShadowRAM (Russians call it cache), the 512x192 resolution, the no-wait in turbo mode (TurboRAM), Covox and Multiport mode stand out. Multiport: a hardware modification, with which the RAM above 128K is managed according to the addressing scheme of other clones, thus achieving better compatibility with ATM Turbo 1, Profi and Scorpion clones. Not specifically Pentagon, but general Spectrum expansions from VMG includes his own versions of AY and Kempston mouse, turbocharging the Beta-128, and fitting the AY chip to push the limits of Pentagon even further. New graphics modes also appeared, which were almost without support at that time. These are the 256x192x16c, 256x96x16c, 128x192x256c, 128x96x256c, as well as 256x192 multicolor 8x1 and 4096 colors palette. The main supporter of these expansions was the Enigma Group also from Kharkiv, who not only used the expansions in their programs, but also indicated their existence in a mini-sysinfo manner. Also related to this topic is the ZX Power diskmag, in which the local Spectrumists wrote about, worth to highlighting the United Coders Software in addition to Enigma. Above to hardware descriptions and wiring diagrams, programs using them were also introduced. In games, end user softwares, demos and gifts from Kharkov using these hardware upgrades are also overrepresented. Can be also observed the widespread use of effects created by hardware devices of VMG and others, such as sound and image digitizers. Gifts are special mini demos of the Russian Spectrum era. Its creators making 'electronic gifts' for another person or team, as well as on preeminent events. ↑date: 2025/01 New generation from Moscow
Pentagon 1024 SLDevelopment of the Pentagon 1024SL, the advent of modern clones was begin by Aleksej Sergeevic Zabin (Алексей Сергеевич Жабин, King of Evil, KoE; Moscow). It started as a school project work, for which was later joined by members of the NedoPC team, also in the capital city. Here we distinguish two main generations of the motherboards, which were manufactured in Zelenograd. The boards were available as blank PCBs or ready-made ones. The Pentagon 1024SL v1. x, which was developed between 2004 and 2005, was based on the 1993 Pentagon 128K 3+ GRM. The author's goal was to create a machine compatible with the timing of the original Spectrum, which ignores the innovations of contemporary super-Spectrums (ATM Turbo and Profi), offering the only extra in memory size. The addressing of one megabyte of RAM is compatible with the KAY 1024 clone introduced in December 1997 (the solution can be traced back to the Profi clone released in 1991). Here it was solved with 1 SIMM module. In fact, the machine is also being apostrophized as a successor to KAY 1024. This is also supported by the fact, that it uses its bus system, the NemoBus, with two such slots on the motherboard. Hence the SL in the name. Since the processor is only a 3.5 MHz by default, the turbo signal from KAY machines is not found on the expansion slot either. The Kempston mouse and joystick interfaces have been integrated, and the ZX Lprint III printer interface support has been implemented at hardware level. The latter is not outputted as a port, because it is not used by anything other than some old printers. The AY/YM chip had to be ordered separately, which sounds stereo when inserted. The Beta-128 system operates at turbo speed similarly to the GRM clones. In addition to the standard Spectrum screen, the machine also supports multicolor mode. The essence of Multicolor mode is, that the Spectrum can be capable of handling smaller attribute area, than the original 8x8 pixels (with only one ink and one paper color is possible), such as 8x1, 8x2, 8x4, 4x1, 4x2. The 2004 Pentagon 1024SL v1.0 was the prototype. The final versions, Pentagon 1024SL v1.4 and Pentagon 1024SL v.1.41, which were made in 2005 are the same in functionality, only differing in visuals. Later, a member of the NedoPC team, Vadim Alekseevic Akimov (Вадим Алексеевич Акимов, Lord Vader, LVD) has added an extension to the series, which allows the machine to run at twice processor speed of 7 MHz. The development of the second generation of Pentagon 1024SL dates back to 2006. The initial Pentagon 1024SL v2.0 and Pentagon 1024SL v2.1 versions were replaced by the final Pentagon 1024SL v2.2, which premiered at the Chaos Constructions 2006 party in St. Petersburg at the end of August. The computer between 2007 and 2010 was the official machine of the ZX Spectrum division in DiHalt party in Dzerzhinsk. The 1991 Pentagon 128K 2+ ATM is simulated by the Altera EPM7128 and EPM3032 CPLD' open source firmware. RAM size is remained 1024K, but got the 3.5/7MHz turbo mode with a software selector installed as default. However, the creator disconnected the turbo from the Beta-128 in sync with ATM 1991 compatibility. Support for the ZX Lprint III remained partial here as well. You can use either a monitor (VGA-RGB) or a TV (with a PAL / NTSC encoder) as screens. AY/YM audio output is from a 2x0.5 Watt amplifier via a stereo jack. It already has three NemoBuses and the motherboard can be bulit into a standard PC/AT case. It got two new graphich modes for the suggestion os Dmitrij Mihajlovich Bystrov (Дмитрий Михайлович Быстров, Alone Coder, AlCo; Ryazan) made possible by the 7 MHz turbo mode. One is 256x192x16C, the other is the Pentagon Overscan mode. The 16C mode contrary to its name, of course, uses only the 15 colors of the Spectrum on the base of the ATM Turbo clone. Its essence, is that any point on the screen can be any color, so we get a similar image to the EGA screen. A member of NedoPC, Dmitrij Dmitriev (Дмитрий Дмитриев, DDp; Izhevsk) made a number of improvements for the machine between July 2007 and September 2009. TurboOFF is a hardware turbo mode switch. This is a very useful modding, as the turbo button is not standard on the machine, because the normal/turbo selection signal is inside the FGPA. The 4096 color palette modding increases the palette to 4096 colors. This expansion has also been released for the ATM Turbo2 +. Some of DDp's firmware contains some changes, bugfixes, and some new features. The first group includes the PAL encoder bugfix, changing the turbo mode with or without Beta Turbo, restoring the screen timing of the original ZX Spectrum (i.e. the 1993 Pentagon GRM/Solon). For the second, the (hardware) 256x192x16C, 320x256, 512x192 resolutions, hardware multicolor, and the GigaScreen mode, which can be combined with each of prevoius. GigaScreen means two screens that use the same graphics but different colors. By changing them quickly, we can theoretically manage 127 virtual colors. It is also possible the 'downgrade' to a simple Pentagon 128K + AY config. The Z-Controller was released in 2007, designed primarily for the above machines, but can be used with any clone with NemoBus. It was debut at the DiHalt 2007 party in June. The card is built around the Altera EPM7128SLC84 CPLD and КР1878ВЕ1 microcontroller. It has a PS/2 compatible keyboard and mouse (Kempston Mouse), IDE (NemoIDE compatible) and SD card connectors. For the Pentagon 1024SL v2.666, the goals were to banish obsolete components from the previous generation, create a flexible architecture, and keep the Pentagon 128K 2+ ATM compatibility. The processor has become a Z80-compatible Z84C0020VEC at 20MHz, but the Altera Cyclone II EP2C8Q208C8N FGPA also emulates a Z80-compatible T80 core ticking up to 28MHz. The FGPA firmware also included the KR1818VG93 floppy controller and the Turbo Sound codes as well as hardware mp3 decoding. The first version of Turbo Sound was released by the Power of Sound team in 1995. The essence of innovation is to use two AY-chips instead of one. Therefore now we can have six channels music.[›] With a combination of the virtual and real processor, the machine can run at 3.5MHz and 14MHz beside the 28MHz mode. The size of the SRAM memory is freely configurable from 512K to 2048K, ROM size has become 512K. Of course, it is also possible to use a specified slice of RAM as Shadow RAM. Peripherals are controlled by a 16/32-bit ARM LPC2294HBD144 controller. The image is obtained via VGA-out with a maximum resolution of 800x600 with 256 colors. The Ethernet part is based on the RTL8019AS chip. It also has a PS/2 mouse and keyboard connector, an SD card port, and a Nemo-compatible IDE controller - thanks to the integration of the Z-Controller introduced earlier. The firmware can be updated via the SD card. A real-time clock was also integrated on the four-layer motherboard. Can be interesting, that the board was flawless at first, so the prototype v2.665 was renamed and became the final version. The development between 2007 and 2008 was unveiled at the ArtField 2008 party, so it was brought by the Santa. The Pentagon 1024SL v2.666LE (light edition) motherboard omitted the Z84 CPU and the Ethernet controller, and the DAC of the video circuit was changed. In order for the significantly more cost-effective two-layer production to take place, either the real CPU or the bus system had to be abandoned. KoE of course opted for the former. Peripherals are controlled here by an ARM LPC2368FBD100. This motherboard was make its first debut at the DiHalt 2009 party in July. The significance of the v2.666 machines, that they were the first ZX Spectrum clones to integrate the controllers of contemporary PC peripherals onto a single board. In August 2015, the Pentagon 1024SL v2.666 Space Version was released, of which all components are Russian-made. The two FGPAS are Russian analogues of Altera EPF10K50RC240, type 5576XC1T from the company Voronezhskogo Zavoda Poluprovodnikovyh Priborov (Воронежского Завода Полупроводниковых Приборов). The microcontroller, designated 1986ВЕ91Т, is a product of PKK Milandr (ПКК Миландр), its closest western counterpart is STM32F103x. The north bridge controls the IDE and CPU RAM, the south one the VGA and video RAM. The microcontroller loads the codes into the FGPA at boot and manages peripherals such as keyboard, mouse and USB. All components are at least 'Russian class 5', so the motherboard can be used on land, water and in the air, even in military missions. [»] Pentagon v.2.666 Final Edition is the final version from 2023 as its name suggests. The central unit of the dual-layer motherboard is the Altera EP3C40Q240C8N FGPA. The emulated Z80 processor at 3.5/28MHz, YM2149 and Turbo Sound were realized in it. The plans also include the implementation of the General Sound sound card and MP3 decoder. There are 2x8 megabytes of SDRAM on board. The LPC1857JBD208 microcontroller from NXP Semiconductor company is responsible for controlling the peripherals. The PS/2 and USB keyboard; mouse connectors, the real-time clock, the double microSD card slot, and the Ethernet and USB connectors are located on the motherboard. Among the classic control ports, Kempston joy, double NES and Genesis gamepads can be used. Standard ZX Spectrum, ATM and 256-color VGA modes up to a resolution of 800x600 can be displayed through the VGA and HDMI outputs. There are three ZXBuses, and as an extra gag, a Z80 processor can be soldered in empty, of which legs do not lead anywhere... [»] Collected firmwares and schematics are and available on KoE's GitHub, [»] as well as on the original support page. [»]
ZX EvolutionThe ZX Evolution (ZX Evo) clone was created in 2009 by NedoPC. The machine is the spiritual successor of the Pentagon 1024SL v2.x and ATM Turbo2+ clones. Both the hardware and software parts of the project are fully open source. The list of developers: the already mentioned LVD and DDp, Roman Valerevich Chunin (Роман Валерьевич Чунин, CHRV) and Vjacheslav Valerevich Savenkov (Вячеслав Валерьевич Савенков, Savelij, Savelij13; Sukhinichi - involved only into software development). During its development, the name Pentevo (Pentagon Evolution) was used, which later became the default firmware name (the firmware is also known as BaseConf). There are three main revisions of the motherboard: A, B and C. The first of these is the experimental, prototype version – considered as a tradition in the team's development. The ZX Evolution rev.A version debuted at the Chaos Constructions 2009 demo party in late August. The microATX motherboard features the Pentagons' three main chips, a Z80-compatible processor (in this case a 3.5/7Mhz Z840008PSC), a Beta controller (KR1818VG93), and a YM2149F sound chip along with 4 megabytes of RAM and 512K of FlashROM. The other components of the Pentagons are simulated by the Altera EP1K50 FGPA, while the peripherals are controlled by the ATMEGA 128 controller. The motherboard, which can be mounted into AT, ATX or microATX cases, comes with PS/2 keyboard and mouse connectors, a single-channel IDE controller, SD(HC) memory card reader, RS-232 serial port, audio in/out connectors and a real-time clock. Both AT and ATX standard power connectors are included, along with two NemoBus slots. For the Spectrum devices, the Kempston joystick, the original keyboard and cassette unit connectors have been integrated. In terms of display, there is a choice of Scart compatible RGB, integrated PAL encoder with composite and S-Video outputs, and a VGA output. For the ZX Evolution rev.B, in addition to the certain bugfixes, the motherboard size has been reduced. The processor has been changed to the 20MHz Z84C0020PEC running at 14MHz. The ZX Evolution rev.C miniITX motherboard is powered by the Z84C0020FEC processor. The AT power and RGB connectors have been removed, as well as the PAL coder (which can still be connected as an external peripheral). However, it got an AY-printer interface, 3 audio inputs and an RS-232-USB bridge with Micro USB output. From this machine, dates the joining of Vitalij Mihalkov (Виталий Михалков, MV1971, tetroid; Novoszibirsk), who took over the production of the motherboard. The colours of the PCB are known to be tetroid red, black and yellow. Currently, the rev.C4 board is available in red and black. Mihail Tarasov (Михаил Тарасов, Mick; Kaluga) made the Pentevo Light board in July 2011 (the PCB still bears the 2010 date). Mikhail's goal was to study the programming of the FGPA in VHDL and Verilog, while making some cosmetic changes to the machine. For example, the cassette unit and audio connectors were moved to a different location, and the machine uses a SIMM memory module. The RGB output and the AT power connector have also disappeared and only the VGA and ATX remains. ↑date: 2024/08
Pentagons of the Internet era After learning about the clones that can be connected to specific teams and individuals, we move on to the world of Internet forum development, where the active forum members are working together to develop newer and newer variants. To identify the machines, I thought it would be useful to introduce the following nomenclature after reviewing the forum posts, technical and photo documentations. The initial base machine name is followed by the "mod.year" tag, then the nickname of the main constructor. In order not to disturb the reading, the inscription of the motherboard, which is only found on 128K motherboards, is added at the end of the paragraph.
Pentagon 48K remakesThe reconstruction of the Pentagon 48K was started with scanning the motherboard by Ovvnex from Kursk, who made the Z01.90 motherboard public in April 2008. [»] The first modern Pentagon is attributed to the already known Moscowian Aleksej Sergeevich Zabin. The Pentagon 48K mod.2008 King of Evil motherboard is completely authentic, the color and shape of the PCB and the components are also reminiscent of the original. It was made as an experimental series, so it was not given a protective coating for economy reasons. [»], [»] After that, Ivan (Иван, Kurgan) created the SprintLayout 4.0 wiring diagram of the clone in July. [»] A few years later, in June 2012, the bug fixes of Moscow-based Abramov Mihail (Абрамов Михаил, aka Mdesk) were published. [»] The hardware guru flagged, but did not fixed the errors on Ivan's board. Heiniken from Gomel, Belarus was joined to the bug hunt in September, as a result of which the new version of the motherboard was born. Some discussion preceded the use of SMD components, but in the end the original, through hole Pentagon 48K mod.2012 Heiniken and Mdesk design was completed. [»] This version was bugfixed and slightly improved by Sergej Bagan (Сергей Баган, prusak). The final version of the Minsk motherboard is the end of March 2013. [»] Pavel Rjabcov (Павел Рябцов, i.e. Paul; Kineshma) has also released the clone of Heiniken and Mdesk in his chipkin.ru online store. From Saint Petersburg vitsserg bought such a motherboard and fixed it at the end of 2018. [»] Paul has of course applied the bug fixes and the new motherboard is already based on the Pentagon 48K mod.2018 vitsserg version. [»] Kurgan's gdv2002 initiative from April 2022 is to create the compact Pentagon 128K on 48K bases. The essence of the very remarkable innovation is that it replaces the RU5 memory chips with the RU7 type, and the AY chip would have been replaced by the КР580ВВ55 chip. The initiative based on Prusak's foundation was unfortunately abandoned. [»] In February 2019, shock__ (aka Shockwav3) from the German capital came out with two expansions for the Pentagon 48K. The first was the MIKAY128 interface. [»] Unlocking of the acronym: "Mem-INT-Kempston AY". So, simultaneously expand the memory to 128K by replacing the RAM chips, change the timings to Pentagon 1991 ATM, and add a Kempston interface and AY chip to the computer. The other is Profi Stereo Covox and Kempston interface. This connects to the three parallel I/O ports of the KR580ВВ55. Two channels address the left and right channels of the Covox according to the Profi scheme, i.e. on ports #3F and #5F, the remaining channel is for the Kempston joystick on port #1F. [»]
Pentagon 128K remakesThe Pentagon 128K mod.2010 molodcov_alex green motherboard's main developer is Aleksandr Molodcov (aka Molodcov Alex, Kolpino). Compared to the original, the right edge here allows for the installation of pre-made extensions: the AY-Kempston combo interface and the NedoPC PAL encoder. The power supply wiring is thicker than the 1991 original, and the Beta-128 interface has two extra diodes for more stable operation. There were two versions: the first board had about 10 bugs, the second (rev.02) reduced them to 3-4. The motherboard is labelled Pentagon 128k 1994 restored by Molodtsov Alex 2010. The aim of Pentagon 128K mod.2011 Zorel project was to produce a classic, yet flawless ATM Pentagon for the 20th anniversary of its birth. Therefore, the then known bugs of the previous motherboard were fixed by Aleksandr Korovnikov (Dnyipro; Ukraine) with the help of forum members. He also cut off the AY/Kempston's and Pal encoder's place. This gave to the original Pentagon motherboard a very similar look. The printer ROM has been banished, but the floppy and power connectors have been made to be standard on the motherboard, which is also green. The keyboard, RGB, beeper, reset button and cassette unit can be connected via a 64-pin header. In addition to the first version in 2011, in the next two years also received bugfixes, so the Pentagon 128K mod.2012 Zorel and Pentagon 128K mod.2013 Zorel board was born. The boards have the following inscriptions, the last digit of the year is of course changing: PENTAGON - 128 -REV201x-. The Pentagon 128K mod.2014 mick_and_solegstar motherboard was designed by the well-known Kaluga-based Mihail Tarasov and Oleg Starichenko (Harkov; Ukraine). The red-coloured motherboard has the AY and Kempston interfaces integrated. The typical capacitors of Pentagons are mounted in SMD form on the backplane. There is a second floppy port with a separate power connector. The power wiring has again been improved. Both the printer port and its ROM have been removed. The former was replaced by the AY-chip output, the latter by a jumper-activated test ROM. The 64-pin connector line is also provided, and a keyboard and mini-card for connecting the Sinclair joystick, invented by Vitaly Mikhalkov, have been added. It is also compatible with the Zorel's base board, not just with the Pentagon 128k (91) modification 2014 board. In 2015, Mikhail Tarasov made yet another version of the Pentagon 128K. The Pentagon 128K mod.2015 mick motherboard doesn't contain any extras compared to the previous one, only bugfixes. The board is labeled Pentagon-128 Designed by Mick 2015. Fortunately, the year of manufacture has been added to the PCB on these. Thus, "2018 Blue Edition" and "2018 Black Edition" each denote a new series of the motherboard, with colors now optional in the spirit of customization. The last member of the project is the Pentagon 128K mod.2018 mick.
In May 2019, elker from Orsk was announced the small-scale production of the GrandRoMax 1 motherboard. [»] The board fits into the Delta-S clone's case after some modding. He also did some minor tunings on the circuit board. The ROM size has been increased, the Beta-128 has been turbocharged. The latter was done based on the publication of On-Line #10, released in November 1995. [»] Both the ROM sets and the normal/turbo Beta-128 modes can be selected by jumper.
With the first wiring diagram of the Pentagon 128K mod.2023 gdv2002, the Kurgan constructor appeared at the zx-pk.ru forum in June of 2023. [»] The motherboard is based on the 2014 version with several modifications. The 7 MHz turbo mode was introduced based on VMG's scheme. The motherboard received a Nemo bus, which is positioned between the motherboard and the Beta-128 interface, following the pattern of Compact clones. The audio amplifier comes from the ZXM-Phoenix. The video output, through dedicated pins, is suitable for installing a PAL encoder or VGA scandoubler. The 5-12 volt converter needed for the VG93 was provided by the Scorpion circuit, and the Beta-128 also received some bug fixes. The wiring of the motherboard changed, allowing for the implementation of a mini and a regular-sized stripboard. The test ROM disappeared, as did the second FDD connector. The floppy drive power connector is also missing from the motherboard. Both the Reset and Magic buttons are present on the board. A bug-fixed version of the schematic appeared two days later. [»] In this version, every small IC received blocking capacitors. Additionally, the power wiring was duplicated, with the main power line running on both sides of the motherboard. The development, for which was joined Aleksandr Evdokimov (Александр Евдокимов) from Saint Petersburg, was transferred to Telegram. The Pentagon 128K mod.2024 gdv2002 and Aleksandr Evdokimov was already born here. Proboterror, who joined to the Telegram group, was build his peripherals on open-source projects for the above machines, and he himself has also made the KiCad wiring diagrams and firmwares available for free access. The first of the two accessories is connected to the side Pentagon connector, the second to the ZX bus. The Pentagon 128K mod.2023 and 2024 interface board started at the end of 2023 and was completed by April of the following year. Built around the ATmega168PA-AU 8-bit RISC AVR microcontroller, the expansion offers standard I/O connectors. These include a VGA Scart-out, a Kempston compatible Sega Megadrive gamepad, and a PS/2 keyboard port, stereo audio output, and in and out of the cassette unit. All above that, the 5 volt power jack connector is present. It is also possible to power the floppy drive (or an emulator) from this card. The standard VGA output can be implemented with soldering the optional RP2040-Zero microcontroller board. The latter expansion is based on the Алекс Екб's circuit, but due to lack of space, the Raspberry Pi Pico was replaced with Zero. The development of ZX-BUS Kempston Mouse Controller for Pentagon 128K mod.2023 and 2024 started after the completion of the previous interface. The controller supports a three-button roller mouse. The card was implemented with the help of the ATMega8 microcontroller and the Altera EPM3032 CPLD, modeled after the nextly mentioned Deltagon clone. Deltagon 1024K Turbo is the variant of Pentagon 1991 for fit into the Delta chassis. Its chief designer is Evgeny Korolev (Евгений Королёв, aka djking26, djking) from Stavropol. The maximum RAM size is 1024K, which can be changed to 128K using a jumper. This is accompanied by 32k cache, which can also be deactivated. 3.5MHz standard and 7MHz turbo modes are also selectable. It is possible to reset to service ROM. It is also possible to invoke it directly with the magic button in addition to the reset. Next to the reset/magic combo there is NemoBUS, which can also be set to Scorpion compatible mode with a jumper. As mass storage, on the first hand, it uses a simplified Gotek/Beta-128 system that supports two drives. These can be Gotek emulated devices or real floppy drives, latter one supported by a power connector. NemoIDE is also present, designed primarily for Compact Flash cards. With a jumper can be optionally set 5 volts power for these cards via the IDE connector. The Kempston joystick and mouse can also be used in turbo mode. The screen has HDMI output, Turbo Sound and Stereo Covox based audio are connected by a 3.5 jack, the simplified cassette unit input is also has the same type of connector. The power input is USB-C standard on version 1.5 meeting the modern requirements. Below the logo, formed by combining the delta and pentagon symbols, is the inscription Делтагон can be read. From Moscow, Alex Podlesnov's development is the Pentagon 128K mod.2024 AlexP, or as he is called the Pentagon Slim. [»] This project was based on the 2014 Pentagon model. The goal of the development was to create a compact, cost-effective machine that could be easily assembled from readily available components. To achieve this, Podlesnov redesigned the wiring, eliminated the side connectors, and used a ‘sandwich’ structure. This design allowed installation of a custom extended keyboard and optional components like the Gotek Slim floppy drive emulator and the RGB-VGA converter between the keyboard and the 31.2x13.5 cm motherboard. The first batch of motherboards, which proved to be bugfree, made in 15 units. Sound output is also available through the TV out DIN connector, which mutes when a 3.5 mm jack is plugged in. An extra-wide power wire and blocking capacitors on the back of the ICs are ensuring stable operation. The final version of the motherboard is v1.4 from February of 2024. Here the Molex power connectors were replaced with USB-C on both sides. RU7 memory modules now can be used instead of RU5. Jumpers on the back of the motherboard allow for selecting the appropriate RAM configuration: either 16 RU5 chips or 8 or 16 RU7 chips. The updated motherboard also features an additional FDD power connector and a reset button. Several minor bugfixes were also implemented. The removal of the Molex power connector necessitated a 5V/12V conversion for the Beta-128, achieved through a mini-circuit mounted on the back or using the CKCS-BS01 board. The keyboard card, which connects via a 10-pin and 26-pin header, includes 16 extra keys. The system is based on the 1991 scheme from the Taganrog Radio Engineering Institute. The extra key codes are stored in the 27C64 EPROM. The keyboard card measures 31.2x10.5 cm and can be attached to any version of the Pentagon Slim motherboard using six screws. It features Tape in and out connectors as well as Sinclair and Kempston interfaces. The motherboard's own type designation is ZX Spectrum Pentagon-128 and ZX Spectrum Pentagon-128 Slim (the latter from version 1.4). The Moscow doc_fbi published the idea of a Pentagon with SMD parts in June 2024. The Pentagon 2014 is also the basis for this, so far the DeepTrace wiring diagram has been created. The motherboard has an integrated NemoIDE controller. The composite image is provided by the AD724JR RGB-PAL encoder. The signals from the PS/2 keyboard are translated by the ATMega 48 microcontroller into ZX Spectrum compatible. The entire system operates at 5 volts, the 12 volts required for the Beta-128 are converted by the MC 34063ADG DC-DC switching power controller. In the spirit of compactness, the AY-3-8913 chip was chosen by the constructor. The also processor runs in 7 MHz turbo mode, the RAM size is 1024K. [»] The Expansion board for Pentagon 128K was born in January 2018 from the design desk of Evgenij Lobodin (JV-Soft, Jamy; Harkov). The constructor was a member of the famous Kharkiv Enigma Group, who actively participated in testing the developments of VMG. His expansion is an all-in-one add-on card that have to be inserted into the socket for the CPU, ROM and one of the RU5 memory chips. This way, the number of unnecessary wirings has been reduced. The card combines familiar Pentagon add-ons with the exception of new screen modes, which are much easier to implement on the motherboard itself. The Turbo Sound section provides six-channel music with two AY/YM chips. This is a bug-free version of the original circuit, which was buggy in the Digital Studio program. It is also possible to use a single sound chip, in which case you get the standard ZX Spectrum 128K sound. The two channels of the stereo Covox are on ports #FB and #7B. The NemoBus was added primarily to connect the General Sound sound card. And the integrated preamp can be used to set the volume mix of beeper, Turbo Sound and General Sound. General Sound (abbreviated: GS) is a development by the St. Petersburg-based X-Trade Group from 1997. One of the most complex peripherals, primarily designed for playing Amiga modules. However, the 12MHz Z80 processor and the 128/512K RAM theoretically allow it to be used as a sort of co-processor, meaning it can take over certain calculations from the Spectrum CPU. Moreover, it can even share its memory with the ZX Spectrum. However, very few programs take advantage of this feature. The memory size can be 512 or 1024K, by soldering one or two 512K SRAM chips. You can of course disable the expansion, in which case you get back a 128K machine. The Z80 processor's 7MHz turbo mode gives a speed increase of one and a half times without using 32K of cache memory, and twice as fast when cache memory is enabled. In addition to the standard 64K Pentagon firmware, alternative ROMs can be burned into the 256K CMOS Flash memory of type 39SF020. The Kempston joystick interface has an autofire option, the IDE controller is based on the NemoIDE controller. In addition to all this, the card also includes some of the usual Pentagon 128K bugfixes. The project is still in the process of being updated.
Pentagon 1024SL remakesBlack_Cat from Saint Petersburg came forward in October 2015 with the proposals for the modifications and bugfixes of Pentagon 1024k v1.4 [»] In addition to the simpler moddings, on the one hand, with integrated microcircuits on the mounting we can improve compatibility and expand the machine. On the other hand, he envisioned a mini-expansion card with a CPLD, which would have been installed on a third Nemo bus. In addition to the descriptions, he also draw wiring diagrams. Among the changes worth to be noted, there are the reset to service ROM, the RAM and ROM manager bugfixes, the 2 megabyte RAM expansion. The replacement of the mouse connected to the obsolete RS232 port was carried out according to the PS/2 standard of Kamil Karimov (Камиль Каримов, Caro). The joystick and printer became port Scorpion standard. The latter is important due to the use of Covox. The timing of memory and screen routines was made to be Pentagon 1991 compatible, the Beta-128 turbo bugfix based on the discmag article of Spectrofon#14 - for this modding required the few discrete circuits on the breadboard. Some new graphical modes could also be implemented in the CPLD: Timex HiColor/BC HiColor; Timex HiRes, BC HiRes, BC & Timex HiRes, as well as the BC FlashColor and BC contour sub-modes. In addition, a few other bugfixes have been presented on the forum. Based on all this, by February 2017, the planned specifications for the Pentagon 2048k v1.5 motherboard were published. [»] The target was ZXM-Phoenix compatibility with Pentagon 1991 timings. He was designed the compatibility with the following machines: ZX 128K/128K+2, Pentagon 128/256/512K, Scorpion 256/1024K, KAY 256/1024K with Nemobus, Profi 1024K and of course the ZXM-Phoenix 2048K. He envisioned the construction in the spirit of the 'DIP Punk' concept. That is, the DIP, SOIC, PLCC, QFP encapsulated microcircuits are soldered on the top of the motherboard, the same type of components and the optional CPLD are soldered on the bottom. The use of FGPA is not allowed. The microATX standard motherboard would have intergrated Caro's mouse and keyboard controller, the Beta-128 and NemoIDE. The partial NemoBus implementation would have been compatible with version 1.2. According to its specifications, it is possible on the one hand, to reconfigure the host machine's RAM into any Z80-based machine through the expansion card, and on the other hand, to expand or replace the memory soldered to the motherboard. In principle, it could able to address 4 megabytes, with Northwood's Pentagon memory manager to be mentioned later. Based on the above plans, in June 2017, Pavel Rjabcov (Павел Рябцов) from Kinesma made a diptrace wiring diagram of a clone for ATX housing. The machine, which also remained on the design table, received a double SIMM-slot and PAL-Coder [»] Aleksandr Pasenko (Александр Пащенко), i.e. Northwood (Dnipro, Ukraine) in March 2016 embraced the Pentagon 1024sl v1.4 upgrade initiative at the TS-Labs forum. [»] The main forum of the initiative soon became the much more popular zx-pk.ru. < a href="https://zx-pk.ru/threads/28489-pentagon-1024-4096-ot-northwood.html?p=938926&viewfull=1#post938926" target="new">[ " ] And with Black_Cat he shared the experience of the development on the host's forum. [»] This is how Northwood's Pentagon got NemoBus version 1.2 instead of 1.0, and Black_Cat's machine got the previously mentioned 4 megabyte memory manager. The planned clone is called Pentagon 1024/4096k Northwood, referring to the creator and the size of the RAM. The main novelty of this, is that in addition to the four NemoBus, it also has an ISA connector. The latter was added due to the connection of the modem to make it easier to exchange data between the machine and the PC. The scheme is based on by Mikhail Kondratev's (Михаил Кондратьев, MI&DI Ltd.) wiring diagram from the mid-'90s. The memory and screen timings are fully compatible with the 1991 ATM Pentagon, but can also be switched to the 1993 Solon as needed. The picture can be viewed on both NTSC and PAL TV. The memory size can be 1 or 4 megabytes using 1 piece of SIMM 30 module. It is possible to completely turn off the expanded memory and use it as a 128K Pentagon. In addition to the Pentagon, it is compatible with the memory management of KAY, Profi, Scorpion and ZXM-Phoenix clones. It is possible to use them on a hybrid at the same boot. So, there is no need to restart the machine, for example, when we want to switch from Pentagon to Scorpion compatible memory management mode. As long as memory allows, these modes can be initialized in parallel. The size of the memory slices can be 128, 256, 512, 1024, 2048 or 4096. By splitting the memory into parts, it is also possible to use pseudo-multitasking. Of the total 128K ROM content, 64K can also be used as Shadow RAM, these are: Gluk Reset Service; TR-DOS; Menu-128; Basic-48. The remaining 64k would have included the ZX Spectrum 128K+3 ROM set, but this option was dropped-along with the +3 expansion bus slot. Turbo and mega turbo modes are also supported. At 7 MHz (no wait) 200%, at 14mhz (wait) 280-295% speed is achieved thanks to the cache memory. The downside of turbo modes, is that not all Z80 processors are stable, but the Z84C0020PEC, for example, is. The system is also sensitive to the type of memory and you have to select from the chips. However, the initial instability of the screen and data bus was resolved. It uses the turbo version of Beta-128, with the modified, corrected circuit (with the already mentioned Spectrofon diskmag 12. and 14. issues published corrections). NemoIDE has also been integrated. The CMOS clock can work with the DS1287, MC146818 or 512VII chips. The Soundrive part has been implemented according to the scheme of Oleg Staricenko (Олег Стариченко). So it is based on two 8-bit tlc7528 DAC chips and automatically activates the Covox compatible mode. In terms of screen modes, in addition to starndart Spectrum, you may be familiar with 8x1 hardware multicolor, 512x192 monchrome (here with free color selection), 256x192x16c, FlashColor and automatic hardware Gigascreen. New features include 512x192 8x8 color, 512x192 8x1 multicolor and 384x288 full screen mode without Border. FlashColor: an innovation from Ukraine in 1998, replacing the most unused flicker (Flash) attribute, offers a palette of 46 colors. In front of a black background (paper can only be this color), a total of 128 shades can be mixed, including the long-missed brown and orange. The entire system is booted by a BIOS setup with a RAM tester, which offers options for selecting screen modes, configuring memory and activating the default ROM. The motherboard itself is an ATX standard complete with an I/O card. The latter features the PS/2 mouse and keyboard, the DB15 connector for the mechanical keyboard, the Kempston joystick, Scart and S-Video output. The other connectors, 3 RCA (video and stereo audio out), 3 jack (audio out, tape in/out), the male DB9 RS-232 and parallel printer DB25 are located on the back coverplates. The I/O minicard includes the AY chip (both two versions can be used in separate slots), Soundrive, and NemoIDE. An another additional card was released, the NemoBus to DivIDE adapter board. It was developed by Black Cat and further developed by Northwood. This was necessary due to the disappearance of the ZX Spectrum 128K+3 expansion slot, which was originally included in the specifications. From the Czech Republic in 2004. November's DivIDE interface has become one of the de facto modern-day storage for ZX Spectrum and clones. According to its European nature, of course, it is sold with the original ZX Spectrum edge connector slot. Thus, the creation of a converter card was justified. The converter can also benefit from connecting other accessories. When using classic General Sound and its modern-day counterpart, the NeoGS sound cards, DivIDE must be placed in a higher priority slot than the sound card for proper operation. Northwood froze the project in November 2020 due to personal reasons.
ZX EvolutionThe ZX Evolution Rev.D started as a community resurrection of NedoPC's machine in 2018. in February. The initiator was Mick, that is, after just over three years, the development was abadoned. [»] ZX Evolution Rev.B3 was born in the Ukrainian capital. Solegstar was asked by Evgenij Lobodin for advice, which version of ZX Evolution to use. Evgenij insisted on the DIP-encapsulated Z80. From there, were two ways: first is to make the version of Rev.C, which uses a DIP processor, or make an updated Rev.B perfected with the Rev.C's innovations. Because the DIP-encapsulated CPU would not have fit on the Rev.C motherboard, therefore solegstar started from rev.B. Permission has been asked from NedoPC for the modifications. In addition to the improvements made by the Rev.C, he replaced some parts, which are intended to facilitate the more reliable operation and easier assembly without affecting the operation. These include beside the CPU, the TSOP46 cased RAM, the AD724 PAL encoder, the DIP packaged ROM, the extra microSD slot, a second audio input, power supply upgrade, and applying all the todo modifications of Rev.C except for moving a jumper to a different place. Five pilot cards were ordered for the Kharkov Spectrumists, and after some bugfix, the final card was born. [»], [»] < p>Under the influence of events in Ukraine, solegstar moved to Krakow. The ZX Evolution Rev.CS, which is considered a developent version, was released in mid-June 2023. Comparing for its starting base, the Rev.C4, it received a HD audio connector, that acts as an audio output and cassette unit input/output. The RS-232 port was replaced by a Sega gamepad connector. On the first days of February in 2024 was released the ZX Evolution rev.CV. Its novelty, that it is possible to connect the video output of the Video-DAC2 via a pin line to the motherboard. Thus, the expansion card can use the VGA connector of the motherboard. [»] Some hardware upgrades for the ZX Evolution have been released from the machine's user base. Chefranov Valentin Aleksandrovich (Чефранов Валентин Александрович, azaz TS-Labs, TSL; Ivano-Frankivszk) was made two peripherals. With his IDE ZX-Evo Video-DAC expansion card, the original 64-colour palette can be 15625 /32768 colors. This is a 2014 hardware, which must be connected to the IDE port. It requires a separate power connector, and its VGA output must be used instead of the motherboard's. It was received a bugfix in 2016. Starting with ZX Evolution rev.C4, it already receives the 5 volt power supply from the IDE port. The other accessory is the ZiFi board. This is a Wi-Fi card based on the ESP8266 Wifi microchip, which is inserted into the X5 port of the motherboard, into the ATMega programming slot. So far it is supported by one program, the ZiFi client, which allows you to listen to ZX Spectrum music, view pictures, download programs and read e-mags. There are versions of the client that work via RS-232 and USB port. In the latter case, you can connect the machine to your PC and use its Internet access. The programs were created by Vladimir Burenko (Владимир Буренко, Hacker VBI; Kaniv, Ukraine). Tetroid later created the Zifi board+joystick card, which also has a Kempston and two Sinclair joystick ports. Three versions of from the basic version and the version with the joystick interface have been produced: revision A, B and C, the last two being the public versions. In addition to the developers, TS-Labs also made the extended TS-Conf configuration, which also supports his two hardwares. [»] The ScorpEvo config of Evgenij Ivanov (Евгений Иванов, Ewgeny7) from Saint Petersburg emulates the Scorpion ZS256 Turbo+ machine. [»] Last but not least, Pong Config simulates the famous arcade machine without using the Z80 processor. European Pentagon developments The news of Russian clones reached Europe at the turn of the millennium. Since then, a number of Pentagon-compatible, mostly FGPA-based machines have appeared, which are belongs more into the hardware emulator category. Let's briefly review the few developments that are dedicated to Pentagon compatibility and do not achieve this by reprogramming an existing flexible architecture. The ZX4MB extension was developed by the Polish Jarek Adamski from 2004 to 2006. This will make the Spectrum Issue 6A motherboard (the others were not tested) compatible with the memory management of the ZX Spectrum 128K, Pentagon 512K and Z88 portable computer. Of course, the possibility of using the memory as shadow RAM and installing a wide variety of operating systems is also given. A prototype version of the expansion, v001, has been released in two copies. This was followed by v006, v106 and v206, with the final version being v315. The expansion consists of three parts, the last of which, the 128K Flash PEROM circuit, can be built and installed separately and optionally. The first step is to replace the lower 16K of memory with at least 32K. This area is the first 16K of the 48K Spectrum in Issue 6A, and the memory (roughly 2x7 kilobytes) of the two parallel screens of the ZX128/P512. The replacement can be done by swapping in the higher capacity DRAM chips, or SRAM modules on mini expansion cards. In the latter case, the power consumption is also reduced (it is possible that other motherboards may not need to replace the 16K with twice as much - as mentioned, this modding is type-specific. Then this original top 32K RAM is replaced by the main 4 megabyte expansion card built from SRAM modules. Finally, installing the optional Flash PEROM circuit closes the line to complete the upgrade. Its ancestor is the ZX512 modding, which was also ZX128 / P512 compatible. To implement it, here also with the upper memory chips needed to replace the 16K lower ones. Then, the empty slots in the upper memory must be filled with 32K DRAMs with 41256, for getting a total of 256K RAM. Finally, solder the remaining 41256 chips on top of these for a total of 512K. Only one prototype from this was made. A multicolor add-on was also made for it, which was not tested. The Pentagon 512kB interface by Czech Jiri Veleba (Velesoft) is an internal expansion for the ZX Spectrum 128K+2 Issue 3 machines from May 2006. This is to be plugged in place of the original ROM and HAL10H8 (PAL10H8) chips. The interface uses 512K of SRAM, plus 128-512K of FlashEPROM. In addition to 512K Pentagon compatibility, it offers a number of other advantages. For example, interoperability with Czech/Slovak D40/D80 disk units and configuring the memory to 128K+2A/+2B/+3/+3B mode. In the latter case, the machine uses its own 128K memory, only the timings were modified. These Spectrum models are already Amstrad developments and have become incompatible with the previous ZX48/128K generations at several points – at least, the memory timing issues are now solved. The so-called snowing bug is also eliminated. This occurs when the processor and the ULA chip responsible for imaging try to access the same memory segment at the same time and causes a very interesting screen effect - often called as a feature. Thanks to our Czech colleagues, the MDOS File Commander and Tools 128 disk utility collection supports extended memory (the PCB caption is PENTAGON 512kB FOR ZX128+2). The External 128-512 kB upgrade for ZX16/48kB, released in early 2009, makes the rubber-keyed little brothers ZX Spectrum 128K and Pentagon 128/256/512K compatible. For the 48K machine, the upper 32K must be removed or disabled first. The expansion works with 128K (628128) or 512K (628512) CMOS SRAM chips, with a switch to select between the two modes (printed circuit board designation ZX128/512). The Profi interface is based on the Pentagon interface from December 2009. It already has 1024K RAM and 128K/512K Flash EPROM. The device is programmable from a PC via JTAG cable. The one megabyte memory can be used as ZX Spectrum (clone) RAM, shadow RAM, and memory for DivIDE, Beta-128 and MB-02+ disk units. In addition to the original ZX Spectrum 128K and Pentagon 128/512/1024K, the card supports the Profi 1024K and Scorpion ZS 1024K memory management schemes. The later, red color v3 version of the interface from the end of 2014 january also has a snow bugfix. The card must be installed in the socket of the Z80 CPU, ROM and HAL10H8 ICs. The 1 megabyte RAM in DivIDE memory can be used to store the RAM/ROM sets. In this case, only one IDE bus needs to be connected to the edge connector to emulate a multi-operating system DivIDE interface. The memory acts as a RAM disk for Beta-128 and MB-02+. It is possible to add a real disk unit to the system in both cases. For the Czech MB-02+ floppy system, this requires an alternative firmware which deactivates the RAM disk of the Profi interface and uses the disk unit's own. (PCB caption: PROFI INTERFACE FOR ZX128(ISS3)). The ZX Nucleon 512K, also made by Czech Petr Valecko (aka CSS Electronics), was designed to be a Pentagon 128/512K compatible clone that fits into the housing of the ZX Spectrum 48K and its replicas. Therefore, the motherboard produced from 2019 inherits the dimensions of the Issue 3B motherboard. The designer already produced a similar board in 2004. At that time, the Didaktik Gama 192K and its variants could be installed in the housing of the Czech/Slovak Didaktik Gama 80K machines. The timings are fully compatible with the Russian clone, but differ in a few other respects. For example, the Beta-128 controller is not integrated, but can be ordered from the creator. However, the original Sinclair edge connector is included. The signals of the Z80 processor are amplified on it, which increases the reliability of operation. The circuitry responsible for the Flash attribute of the original Pentagon machines has also been redesigned in order to better simulate the original Spectrum. The imaging and power solutions are also more advanced than the Russian clone, and the reset is more reliable. The control of the ports (ULA, AY, memory access, etc.) was solved by the designer with a GAL chip. The memory is implemented with a single SRAM, which can be set within 128/512K modes by a micro switch. The AY interface is also integrated, with a micro switch to select ACB or ACB stereo mode. The output is a stereo jack soldered in place of the original MIC connector. The beeper and tape in/out signals are also included in this audio output. The load/save inputs for the tape unit are also on a stereo jack, in place of the EAR. The load signal amplifier has also been improved over the original. The screen output is an 8-pin mini DIN connector with RGB/S-VHS signals. Version 1A was the prototype, with subsequent versions being commercially available from August of 2019. Since v2A onwards (October 2019), the picture quality has also improved. In addition, all motherboards undergo a two-hour stress test from version 2 onwards. One month later, v3A was released, with additional minor bugfixes and improvements. Az utolsó verziónál, a 3B-nél a képminőség javult és a portdekóder került egyszerűsítésre. ↑date: 2024/12 |
| Spektr BK-001 (Спектр БК-001)
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Unstable and Incompatible Clone from Banks of Volga The Spektr BK-001 (Спектр БК-001) 48K clone was produced between 1990 and 1994 in Tver at the Tverskoj zavod elektroapparatury (Тверской завод электроаппаратуры - ЭЛТОР) factory. The clone should not be confused with the similarly named Спектр-001 computer, which is a Радио-86РК compatible machine. The Spektr BK-001 had a modified ROM that included Russification and cassette testing, which significantly reduced compatibility. The clone booted with the inscription (s) СПЕКТР БК-001 ТВЕРЬ 1990. However, according to photos, using the original ROM was not a major issue. Additionally, the hardware did not have a good reputation for quality, being sensitive to power supply and overheating. The wiring could detach from the motherboard due to heat, making the machine virtually unrepairable. Two main versions were released. The first had a membrane keyboard and a 5-volt power supply, while the later version had a regular keyboard and a 9-volt unit, converted to 5 volts internally. The transition between the two generations happened in the spring of 1993. A version with a reed switch also appeared, but little is known about it; it was likely a prototype. This is supported by the absence of TV/RGB mode selector switches and corresponding wiring. The order of the connectors is as follows: the first group of three is for TV/RGB, tape recorder, joystick, and finally the power supply. The reset button and the previously mentioned TV/RGB mode selector switches are located under the right hand.
Mick recreates his first clone This machine was the first Spectrum clone of the already-mentioned Mihail Tarasov (Михаил Тарасов, Mick, Micklab) from Kaluga, so it's no surprise that it has been recreated by him. Mick decided to redraw the motherboard authentically, but not with millimeter-by-millimeter accuracy. After a short break, the P-CAD 2002 schematic was completed in March 2016. [»] After this, he archived and documented the work on his website. [»] The motherboard and kit are now available for purchase on several webpages.
↑date: 2024/11 |
1990&1993. 
2016/03. |
| Lugan PK-90
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5.1. Not much information can be found about the Lugan PK-90 clone. Based on its name, it can be inferred that it was made in the Lugansk region in 1990. The date is confirmed by the inscriptions on the motherboard and the boot screen (Personal Computer PK-90), [»] while the location is mentioned in the documentation. It can be considered as a modification of the Leningrad 1 with soldered connectors and edge connector on the motherboard. It has outputs for keyboard, Kempston joystick, audio/aux, and video/cassette unit. The documentation mentions as constacts the Iskra office in Lugansk (also known as Luhansk) and the microEVM laboratory in Stakhanov (Kadiivka). [»] The former could have been the marketing and business department, while the latter was the manufacturing headquarters.
5.2. The reconstruction of the motherboard is credited to djking from Stavropol. Using the photos of the forum member NikonD3300, he created the circuit diagrams at the end of November 2022. [»] Unfortunately, the identification of some capacitors is not yet realized, so the complete revival is still awaited.
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1990. |
| ALF
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The unsuccessful rival of Dendy The Elf TV console is one of the least known game consoles. It was based on the ZX Spectrum 48K and was made in Belarus. The hardware was manufactured by the Brest-based Cvetotron factory, with the development done by the factory's in-house development team, SKB West. These consoles were produced in the early 90s, in approximately 2000 units. The start of production was likely in 1991. The relatively small size suggests a high level of integration. The double-sided, silkscreen-masked PCB features the KP1858BM1 processor (a Z80A clone), the T34VG1 ULA clone, two 32K KR565RU11 RAM chips, which are the analogs of the 4464. The video output is handled by a Secam encoder and RF modulator, with RGB and RF outputs. There are also two proprietary joystick ports. It also includes a built-in speaker. The ROMs used can be either 27C256, 27C512, or 27C010. In the 32K variant, it contains the 48K Speccy ROM and the system boot ROM. Most games require the former. The larger ROM versions also include built-in games. The version without games displays a blank screen upon startup, while the version with built-in games shows the Belarusian titles of games. When a cartridge is inserted, the console boots into a menu of games burned into the respective ROM. Another variant was released, named Elf-01 in the user manual. This version does not include a speaker, Secam decoder and RF output, but it does have a connector for keyboard. A white-colored variation also appeared, which includes a joystick instead of controllers. There were two main variations of ROM cards. One could accommodate 8 pieces of 128K EPROMs, while the other could accommodate two. With some hacking, it is possible to use 256K modules, but the maximum addressable ROM size is 1024K. In terms of D-pads, the NES/Dendy was the inspiration, but here are only two (fire) buttons. The games are classic ZX-era titles, adapted for console controls and with short descriptions.
Expanded rebuild The main coordinator of the modern developments is Sergey Bagan, also known as Prusak (ex-Pro Hackers' Dynasty, Minsk). First, let's go through the developments intended for the original console. To integrate the AY chip, it was built into the cartridges, which communicates with the Z80 processor through the free pins. For this, it is also necessary to modify the amplifier circuit in the console, after which the AY and beeper are mixed to the output. In some clones, including the ALF, the black color does not differ in the normal and bright versions. To eliminate this, a modding option activated by a switch was created. The 128K expansion was based on the ZX Review issue 2. In this, with the readers shared his circuit diagram Boris Ivanov from Smolenks. Although the T34VG1 was designed for 48K clones, the memory expansion can also be achieved here with six logic circuits and the RAM chips. In this case, the latter meant two additional RU11 chips. Both breadboard and complete PCB versions were created. [»] The author also created a Nemo bus ROM grabber, of course, with its corresponding software. The reconstruction of the console began at the end of October 2015. [»] With the help of Prusak, Dmitry Pugachyov (aka DJs3000) from Moscow created a new motherboard, of which the beta version was released in November 2015. [»] As a novelty, a complete RGB circuit, PAL encoder, AY chip, and two Dendy standard joystick ports were implemented. This beta version, of course, still had bugs, but could be fixed with wiring. Five samples were made, from one was given to Prusak for debugging purposes. The final version was released in April 2016 in a dozen copies, with detailed documentation of the assembly and fine-tuning process. A test ROM was also released. [»] Prusak also created a 3D case for the motherboard. The next iteration was the Elf-128 2023 v1.1. Of course it was received 128K of RAM. Another novelty is a 32K SRAM for saving game positions if someone write a game that supports it. Another novelty is a Pico-based VGA/HDMI output. The four-layer PCB has numerous outputs. On one hand, there are the classic and 'modern' variants of the same outputs. These include double ALF and Dendy joystick ports, DC 5.5 and USB-C power inputs, stereo RCA and jack audio outputs. As video outputs, PAL composite, S-Video, and RGB can be selected. Detailed instructions are also provided for assembly and setup. As an experiment, the console was also supplemented to be a complete ZX Spectrum with a Beta-128 interface and keyboard. In July 2022, new cartridges were made, which can use 128/256/512 and 1024K EPROMs or 128/256/512K FlashROMs. If you want to install a 64K or smaller units, there is also an option requiring to solder two optional microchips. The height of the cartridges is smaller than the original since the PCB is smaller in size. [»]
↑date: 2023/01 |
több kép
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2016/04. 
2016/09. |
| Orel BK-08 (Орель БК-08)
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Ukraine's First Mass Clone The Orel BK-08 (Видеоигровой компьютер Орель БК-08, or Video-game computer Orel BK-08) was a clone developed by the Dnieper Machine-Building Plant between 1989 and 1990. The machine was manufactured from 1991 to 1995, with approximately 25,000 units produced. Its price was slightly over 1000 rubles in September 1991. [»], [»], [»] The first mention of the БК-08-1 variant was in April 1992, and it is known that it weighed 300 grams more than the base model. [»] Late models from 1994 and early models from 1995 were released with the Ukrainian state quality assurance logo sticker, which was placed on the box and the back of the machine. Since this logo was introduced in 1996, the computers were definitely available in that year. [»], [»], [»], [»], [»], [»] Its name is derived from the Orel River near the city, and cassette decks were also marketed under the same brand name. [»] This is a 48K clone with 64K memory made with 8 pieces of RU5B chips, of which 16K can be used as ShadowRAM. The ROM was implemented with two 8Kbyte chips. There is still space for the same amount of installations, which was hardly ever used - given the ShadowRAM option. The contents of the shadow RAM are not lost during a hardware reset. In addition to shadowRAM, IS-DOS also used the extra 16K as a buffer. [»] Just like with the Baltik 48K, the numerous additional features and solutions that increase incompatibility suggest that it was originally intended for industrial use. Its predecessor was the ПК-08 computer, which was designed for a railway control system. Basic was likely optional, and perhaps the MZ80 monitor would have been the main operating system. It connected to the railway system through the edge connector. [»] The book discussing the DMZ history mentions September 1988 as the beginning of Orel-BK08 distribution. If the date is true, this refers to the PK-08. Because neither the factory serial numbers, nor the documentation, nor the computer's construction supports the 1988 date for the Orel BK-08. It is possible that version 1.0 of Basic was tested on the PK-08. [»] The handling of RAM, similar to the Pentagon, did not slow down when the ULA and processor address the same memory area in parallel. The tacts/frame is 69888, the same as the original ZX Spectrum 48K. [»], [»] Regarding the back panel connectors, there is a 24-volt power supply, TV/RGB, Tape out and in, and then a combined Kempston/double Sinclair joystick connector. That is, the two connectors accept two Sinclair 2 joysticks, and the Kempston joystick can be plugged into either port. This solution did not improve the already poor compatibility of the Orel. [»] On the front panel, next to the power LED, there are reset and NMI microswitches, and under a cover, the ZX bus is located. The latter, according to Russian standar, has a 2.5mm pin spacing. The 24-volt input is converted to 5 volts inside the machine. Due to the complexity of the power supply, it often malfunctioned, so a popular mod was to implement direct 5-volt power supply. [»], [»] The keyboard has 67 keys with Cyrillic and Latin inscriptions, between which you can choose with mode selectors. With the RUS button can be used to lock it like a Caps Lock, and with the two R/A buttons can select Russian/English characters similarly to shift. [»] The Russified ROM boots with the inscription Бейсик-система вер. 2.0, using KOI-7 encoding. [»], [»] Thanks to the reed keys, it was one of, if not the highest quality ZX Spectrum clone keyboard. [»] Most machines were sold with a light gray or bluish gray machine housing (less often with a combination of the two colors), but there are also brown and dark gray cases - these are members of the very first and last generation, respectively. The color of the keyboard also changed, sometimes the basic keys, sometimes the others were lighter or darker. The machine was initially shipped with three software, the MZ-80 monitor program, a test program, and a Laser Basic-based advertising program. Detailed user guides were provided for both the machine and the programs. The MZ80 monitor program is loaded into the shadowRAM and can be called with the NMI button. The copyright boot message is (C) 1989 Monitor MZ80 Design Club "Processor". The test program file name is TSTBK.0990, which leads us to the September 1990 release. The date of the advertising program based on Laser Basic is also 1990. Created by Trocenko A. and Taras W. [»] The local Spectrum users join the manufacturer In 1993, a new program compilation was released. This included both new and old classic programs alongside the three applications mentioned above. It can actually be considered a firmware update pack, as some of the programs replace the ROM content through the ShadowRAM. It partly targeted cassette users with turbo loading, and partly aimed to support their then-introduced Beta controller at the time of release. [»] Getting know about the RAPID-OS can serve as a background. Its author is Vladimir Ivanovic (Владимир Иванович) from 1992. The local Spectrumist also sold ROMs and tapes and ran a computer club too. His modded ROM was primarily created for turbo loading, but it also significantly improved compatibility. [»] It is booting with the BASIC/OS-Rapid (c) Vlad, 1992 with yellow text on a black background. It is using simplified error messages. [»] The turbo modification was certainly due to the reliable cassette unit circuit of the Orel. [»] The version made with TR-DOS used the 5.04T version. [»] The corresponding copying program was Sormos3 from 1990 from Poltava, which could handle the speeds of 1x, 2, and 3x, and was already included on this tape. [»] (This program is actually based on the Spanish Kato's Tape-File Copy program hack) The ZX/OS-93 found on the factory tape can be the DMZ equivalent of Vlad's RAPID-OS from 1993. [»], [»] The OS 'Cascade' was the operating system of the DMZ employees, and the Turbodrive was likely an extension of this with the Beta turbo. More details on the next paragraph. Three types of Beta-128 interface were developed for the machine. The first of the unofficial controllers, Rapid, was the work of Sergej Brilev (Сергей Брилев) and Leonid Margolin (Леонид Марголин), and also included a Kempston Centronics E interface. Its release date was March 1993. It is based on the circuit diagram of Alex Krupp from Kyiv. It could handle two drives and it was the larger, made with 555/1533 chips. [»] The second one, a smaller version, was based on К556РТ4 chips, and existed in several sub-versions. [»] Both were made by small-scale manufacturers, without an official producer, and they required two modifications to the computer's motherboard. The third one, which could be purchased from DMZ employees at the Meteor Ice Palace radio market, naturally did not require any modifications of the machine. This one boots with the 1993 VitaSoft OS CASCADE inscription, and also uses simplified error messages. [»] The local Spectrum software and hardware developers: Mihail Borisov (Михаил Борисов, Barmaley_m, Bogo Software), Andrej Stepanovic Sendeckij (Андрей Степанович Сендецкий - Andrew Strikes Code, aka ASC), Aleksandr Safir (Александр Шафир, ASH), Andrej Getalo (Focal Soft, Андрей Гетало), Timur Portjanin (Тимур Портянин), Oleg Polovinko (Олег Половинко), Vitalij Sevcuk (Виталий Шевчук, SVVSoft). Borisov created his firmwares with Arcadi Pushnikov. Their first expansion was Bogobasic 48K, a variation between Sinclair 48K and Orel. It handles the extended keyboard, but omits the Russian language support. Thanks to two bug fixes, it doesn't consume 5 bytes of RAM, as opposed to other shadowRAM-based operating systems. [»], [»] Graphic commands were accelerated, TR-DOS is accessible from Basic, and it's also compatible with 128K Basic. It boots with the inscription (c) 1993 Operating System V3.0 in yellow font on a blue background. [»] Getalo based on this created Bogobasic 48/128K, which included the fixes but removed the handling of the extended keyboard. The text changed to (c) 1994 Operating System 128K retaining the colors. [»] Since, besides reparining the Orel computers, he was dealing with 128K expansion, [»] so sooner or later was expected the release of the operating system supporting 128K. The Monitor Z80 64K/160K is also Borisov and Pushnikov's work from the summer of 1993 (version numbering started with 2.0). It has a disassembler and supports 2x, 3x turbo loading. It doesn't trashing the memory just like Bogobasic. It only changes the top 4 bytes used as a stack, but this is very rarely a problem. There was also a later version that supported 160K RAM and TR-DOS and even offered some non-standard solutions. So this version is not compatible with the factory Orel. [»], [»] The 256К "LSY-Computer" is the expansion card of the local Spectrumists from 1995, which, as its name suggests, is a 256K memory expansion. It is not compatible with any other standard, the creators made it to facilitate their own work, they did not plan to spread it more widely. Thus, the native 256K RAM mode was only supported by one game and one user program. The latter was created by Borisov. This is an EPROM burner software, and since it supported the 64KByte 27512 type, it used two buffers (reference and read), which required 256K RAM. The release date of OmniProg for "LSY-Computer" is January 1996. [»] [»] Due to the non-existent software support, the average power user could only see one benefit of the multi-version card: due to the better memory chips, the turbo boost was more efficient in 128K mode. A version containing an AY-chip was also made for Timur Portyanin. SVV further developed the card with 512K RAM (using a SIMM module) and also added an AY-chip. [»], [»] Let's see what main functions the card can fulfill. The part above 128K RAM could also be used as shadowRAM for Basic-48, Basic-128 and TR-DOS, thus ensuring even better compatibility than Bogobasic. The extension supports ASC CP/M, the operating system written by ASC and ASH jointly. [»] It uses logical drives for disk access. A: is the RAM disk that CP/M does not have access to. B: drive is the first ASC CP/M drive, C: is the CP/M drive of a forgotten type. D: is an ATM CP/M compatible drive. The E: is for ASC Music Show (AMS) format, that is already the second real drive. The author's music program used its own record format, and the expansion naturally supported this as well. The F: is the second drive of ASC CP/M. The role of G: and H: floppies has also been forgotten. The original ASC CP/M was written on an original ZX Spectrum 128K+2 (?) with 144K RAM (?) in April of 1992 (v2.0). Bogo adapted the 144K+English keyboard configuration. Bogo adapted the 144K+English keyboard configuration to the 256K+Orel keyboard combo. (cpm144.sys with azkeyb.mac vs cpm256.sys with mzkeyb.mac ). The ASC CP/M used the CP866 code page, which is much more advantageous, as the pseudographic cataracts following the characters of the ABC are in the same place as on the 437 code page. [»] The system could also be used with IS-DOS, Bogo created the Orel keyboard driver for this as well. (ttyin56.sys with mzkeyb) Both ASC CP/M and IS-DOS can handle RAMdrive. Borisov created his own firmware for the card, the LSY-Setup back in 1995. [»]. [»] Whoever wants to try the expansion, can do so with an UnrealSpeccy hack. [»] Some other information about the development can be read on the forum. [»] Of course, several smaller expansions were made. The card containing the AY-chip had to be plugged into the processor socket, just like at the Pentagon. [»], [»] The 128K+AY mini-card is Getalo's work, but Borisov also helped. By reducing the number of chips, the card became record-small. [»] 128K (Getalo) and 512K RAM expansions were also made. [»] These were implemented with dual-row RU5 and RU7 memory chips, [»] except for the already mentioned SIMM modding of SVV.
Beta Disk remake and Pentagon compatibility In May 2011, Anatolij Gajvoronskij (Zorel) from Dnipro was remade the smaller Noname BDI remake, which according to tests works with Leningrad 1 and 2 machines, and theoretically with any 48/128K clone. [»] The second, bug-fixed version of the disk controller was also released in September. [»] The firmware, circuit diagram with Gerber files, installation manual, and ROM image are all downloadable from the forum. Oleg Staricenko (Олег Стариченко, aka solegstar) from Kharkiv assisted in extracting the firmware. The 1 megabyte RAM expansion using Pentagon 1024K timings, was released in mid-July 2012. It was created by Andrej Kilcinskij (Андрей Кильчинский, aka oraclea) living in Enerhodar. The initiative started in November 2010. [»] The expansion eventually included a memory module and an EPM3128ATC100-10 CPLD, which fits comfortably in the empty ROM sockets. [»] Jurij Onufrijcuk (Юрий Онуфрийчук aka juka1868) also from Dnipro, came out with the 128K RAM+TR-DOS bugfix [»] and the modified Kempston joystick circuitry for the circuit at the end of August 2015. [»]
↑date: 2024/10 |
1991.
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| RU-3. Profi |
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3.1. The Profi in the 90s The history of Profi clones is still unclear. All is certain, that its developers, Mikhail Jacyk and Viktor Tereshhenko. After they registered the Profi PLL company name, teamed up with the Russian-Lebanese-Spanish joint venture Kramis with the aim of continuation it in 1991. By the end of this year, the first version of the machine, 3.1 was completed. Its bugfixed version, the 3.2 was launched in early 1992. Shortly after, a dispute arose between the developers and Kramis, and the two men left the company in 1992. After that, for Profi PLL, Dmitry Novikov was hired for hardware development, Mikhail Markovsky (aka Klug) for writing the firmware/software. The hardware designers of Kramis were Kirill Gromov (Chung Software) and Mikhail Hohlov. The list of their coders: Alexei Emelyanov (AvE), Andrei Krestyanikov (KiiA), Mikhail Poznjansky (Micco Software) and Dmitry Pismenny. Sergey Kutin has been became the company's documenter So from now on we can talk about two clone variants, just like in the case of ATM. The one from the original developers, i.e. from Profi PLL, and the another is the Kramis version. The latter is the more common one and is also considered to be 'the real clone'. Kramis later changed its name to Condor. It's very likely, that the Profi is the only ZX clone consisting of two circuit boards. First is the motherboard itself, which is functional on its own. The another is the peripheral card. Software and hardware compatibility issues are not known. Any motherboard and peripheral card can be combined. However, if the peripheral card is newer than the motherboard, the new add-ons on it will not work. Due to the placement of the boards, these clones can be installed both into the Electronika BK's case (with a height spacer) and also into a PC case Of course, the Profi has also became the victim of piracy, diminishing the reputation of the original machines. Interestingly, Condor company has done nothing to remedy this, only a notifying text on the system disk warns those who wish to pirate. The first generation was the original v3.x series, i.e. the Profi (without any distinguishing markings, although its first series was also marketed as the Sinclair Profi). This motherboard was made without a protective mask, and has no colours in the 512x240 resolution Profi mode. The 6 and 7 MHz turbo modes were already available here. The memory chips were placed in a 'checkerboard' order on the v3.1 and v3.2 boards. On the peripheral board, the disk drive controller, sound chip, parallel I/O port and Kempston joystick interface were integrated. Memory expansion can also be solved here. So, in addition to the maximum 512K of the motherboard, the same amount can be added to the other card. Both Profi PLL and Kramis have been distributed this version. For the transitional Profi+ series, developed by Kramis, starting with v4.0, the boards have already been given a protective mask and the memory chips are in a traditional form. In Profi mode, it now ran in 16 colours. The peripheral card remained the same. In December 1993, v4.0 was surely released. v4.01 and v4.02 motherboards are bugfixed versions of the previous ones. The peripheral board was re-designed, with an optional RS-232 serial port and a real-time clock. Presumably April 1994 is the market release date for the v4.0x versions. For the v5.0x machines (Profi 2+) the memory expandable on the motherboard up to 1024K, the NemoIDE controller was installed on the peripheral PCB as a new feature. The serial port and the real-time clock are now standard. The 16 colours of the native graphics mode can here be selected from a palette of 256 colours. The company has now advertised its product here under the name Condor. v5.01 was buggy, v5.02 is bug-free. In v5.03 (Profi 3+) the wiring diagram has been slightly modified. Thanks to this, instead of the 9-10MHz maximum of the previous versions, it can now be officially boosted up to 12 MHz. With some modding up to 21MHz is also possibleble. We first read about the v5.03 Profi in issue 7 of On-Line from Chung Software in October of 1995. [»] Kramis/Condor also developed some add-on cards for the machines, such as XT keyboard controller and Covox. The version numbers of these are not in accordance with the motherboard/peripheral board combo. According to the found schematics of the Profi LLP , the futher developed v6.2's date, which was followed the 3.2 version is May 1993. The motherboard was made from this, the peripheral board remained the 3.2. The v6.3 motherboard-peripheral board combo (October-November 1993) is incomplete and buggy. In any case, the 7MHz no wait, full travel turbo mode was implemented in version 6, unfortunately not in the higher processor speeds. Of course, it also got a color mode. The Profi v6.2 (and its replica, the 6.2 Rev.B) measures 33,5 x 20 cm, the Profi v6.3 is 33,5 x 16 cm. By May 1994 the project was discontinued and archived. It was because the Profi was burgled, and they also financially weakened. v5.04, also known as v7.1, was Condor's last attempt back in 1996. Around 1996-97 they were only working with Amigas, and they were later bought by Dendy, a Nintendo cloning company, which went bankrupt in 1998. The further development of the Condor line started from the several times mentioned NedoPC. Vyacheslav Valerevich Savenkov (aka Savelij , Savelij13; Sukhinichi) presented the Profi v5.04.mod2008 Savelij motherboard in June 2008. Compared to its predecessors, it got direct RGB output and returned to 2.54cm pin spacing. The 'series production' was undertaken by Aleksey Sergeevich Zabin (King of Evil , KoE ) from the Russian capital. [»] The Kharkiv-based garlands took Savelij's work as a basis for the creation of Profi v5.04+.mod2011 garlands, an idea he pitched on the forum in early 2011. His plan for both the motherboard card, [»], and the peripheral card was to mass produce them in small series. [»] The memory on the bottom card can be expanded up to 2/4 megabytes with RU7 chips, RU5+SIM30 combo, two SIM30 and single SIM72 memory modules, of course the firmware can only address up to 1 megabyte of RAM. As for the power connectors, a molex, two PLD-4 and a PLD-10 pin header have been integrated. The ROM is stored in a 128K 29EE011CMOS Flash memory. The audio is routed out on a 3.5 jack and 4 pin header, the tape I/O is routed out on 5 pins. Video output is a 5x2 pin BH-10 connector on the board, which has to be connected to a PAL encoder. The soon describen ORQGE signal mod of solegstar is also integrated. A full year of collaborative development was resulted in the release of the bottom board on the virtual market. [»] Unfortunately garland had difficulties in completing the project (traveling abroad, lightning and fire damage, difficulties in sourcing parts). The peripheral board was thus only realized on plans, and the finished boards were still not available. The development was therefore taken over by Oleg Starichenko (solegstar, also from Kharkiv). For first, the peripheral card received a virtual bugfix for the 2011 Santa Claus. [»] The already actually implemented Profi v5.05.mod2012 solegstar peripheral board is a bugfixed 5.04+ from April 2012. [»] Two years later were released the Profi v5.06.mod2014 solegstar lower [»] and upper [»] complete cards. The bottom one is actually an upgrade from version 5.05. The top is based on solegstar's own development, a similar expansion card for the Robik clone. The peripheral board was designed by the constructor to can be used with any base board after minimal modifications. Production for the forum members was this time organized by Alexander Korovnikov (Zorel) from Dnipropetrovsk. The peripheral card is the same size as the 5.03 and was implemented with programmable logic circuits. The mass storage is SD card based on Z-Controller and also uses the NemoIDE with CF-IDE adapter. The image is obtained through zst's VGA converter as well as NedoPC's PAL coder. It has an integrated ZXMC card for connecting PS/2 mouse and keyboard. The ZXMC (ZX Multi Card) is Kamil Karimov's interface from April 2005. It can be used to connect PS/2 keyboard and mouse, RS-232 port modem to Spectrum. It also includes a real-time clock. It can be expanded modularly. For regarding music, Turbo Sound, SAA1099 and the dual TLC7528 based SounDrive have been implemented. Of course, you can mix the sounds of these freely The SounDrive is an extension of Flash Inc. from 1995. It is connecting four Covoxes together, so that each channel of the Amiga modules has a separate D/A converter. Pavel Rjabcov (aka Paul; Kineshma) [»], perestoronin from Moscow announced the small-scale production of the 5.06 set in September. [»] The last series of the Profi PLL's clone has also been attempted to be resurrected. Mikhail Abramov (Mdesk) released the v6.2revB from Moscow, so the Profi v6.2 rev.B.mod2010 Mdesk board on the last day of March 2010. [»] This is a bugfixed version based on the 1993 documentation. Solegstar attempted to resurrect the v6.3 peripheral card in late 2017, but as it was expected, this was unfortunately failed. [»] The Karabas Pro is developed by the Ukrainian Andy Karpov (andykarpov) and is a Pro v5.x compatible member of his Karabas FGPA-based clone series. The machine is built around the Altera EP4CE10 FGPA and the EPM3128 CPLD. The Nikopol-based hardware developer started development in July 2020, also involving members of the zx.pk.ru forum. It has the 512x240x16 resolution from a 256-colour palette, a floppy-drive controller and an IDE controller with CF card. It supports Profi's real-time clock and the use of full 1024K. The PS/2 keyboard simulates XT keyboard layout, the PS/2 compatible mouse works with Kempston and Microsoft serial mouse protocols. The image is outputted via a standard VGA connector. Regarding the sound, TurboSound, SounDrive and the SAA1099 sounds chip are implemented through a TDA end-amplifier. In addition to the Kempston compatible joystick, it also supports 3 and 6 button Sega gamepads. It also works in 7 MHz no wait and 14 MHz wait turbo modes. The SD controller is certainly Z-Controller standard. The 115200 baud serial port is based on the ZX Uno's specifications. The ROM size has also been increased. The latest 'E' revision alread has 6 megabytes of SRAM. Subsequent boards marked Ё and Ї have been given Russian and Ukrainian lettering, along with the usual bugfixes. The PCB is sized in order to fit under the 3.5 floppy drives. This time, the clone is not in the Profi topics, but in the FGPA clones forum. [»] All the hardware/firmware documentation for the clone is available on the author's Github. [»] The constructor from Prague Jiri Veleba's (Velesoft) Profi interface was described in the middle of chapter 2.4. [»] 3.3. Peripherals from the community Kamil Karimov (Caro) from Ekaterinburg came up with PS/2-XT keyboard adapter v3.2 for Profi v3.x, v4.x, v5.x card in late November 2008. The core of the circuit is the ATtiny2313 or AT90S2313 microcontroller. The firmware and PCB drawing are also available from the forum. According to its name, it works with all v3.x, v4.x and v5.x Profi versions. For v3.x machines, the adapter works with a combination of a 16-pin connector and a four pins one. The v4.x/5.x versions have an integrated 20-pin connector. [»] Another modding news from Chaykovsky. Sergey Borzenko , aka Anykey released the 1 megabyte SIMM30 module for Profi v3.x and CP/M color mod for Profi v3.x with schematics in September 2010. [»] The former also received a community bugfix in July 2011 from oracleua of Enerhodar, Ukraine. Soon owners of version 4.01 could also upgrade their machines with a single 1 megabyte module. [»] A series of improvements have also been released for Profis from the solegstar. He modded and tested them on his own version 3.2 machine. These changes have been tested-adapted by John North (Izhevsk) on versions 4.x, and by Savelij on 5.x. The Profi ZX-Bus-Expander for Profi v3.x, v4.x, v5.x is also from solegstar and he was just made it under the Christmas tree in 2010. The card, which contains four buffered ZX-Bus slots, is based on a schematic from the X-Trade Group in St Petersburg, and was featured in Spectrum Expert #02 diskmag (March 1998). [»] Two versions of the card were produced, the first being the prototype. The second is, of course, the more compact design. The constructor has posted on the forum detailed descriptions and wiring diagrams, how to fit it to the different versions of the Profi clones with the help of forum members. There are immediately two types of moddings to choose from: minimal and full. [»] Of course, the card, was soon available in both vertical and horizontal designs on the virtual market. [»] The IORQGE signal mod forProfi v3.x, v4.x, v5.x allows you to use the NemoIDE controller without any problems with the Profi clones, which originally had a ZX Spectrum 128K (more or less...) compatible edge connector. The September 2011 upgrade activates the IORQGE signal on the bus and at the same time prevents conflict with the AY chip. The modding, which is available separately for Profi 3.x/4.x and 5.x versions (the latter of course from Savelij), may also be beneficial for other ZX-Bus compatible cards. [»]
The #DFD port mod Profi v3.x, v4.x, v5.x is designed to allow you to use the 768K RAM disk in ZX Spectrum 128K mode right after power up. [»] The original schematic is from the Spectrofon diskmag issues 16 [»]/17. [»] (December 1995, February 1996), ZX Element #01 [»] (November 1997) and ZX Ferrum #02 [»] (April 2004). Starichenko's earliest wiring diagram is from November 2011.
The January 2012 #BFFD port mod for Profi v3.x, v4.0 for the peripheral boards bug-fixes the data registers on AY/YM chips. The bug is undetectable for general use, but when using Turbo Sound, the problem is already occurring on first generation cards. [»]
As expected, the Pentagon 128K 2+ ATM timings mod for Profi v3.x, v4.x, v5.x 'package' has been released. The hardware-firmware modding for v3.xx and v4.xx clones was released in late November 2011. In addition to Solegstar's own firmvare mod, he was published Mikhail Markovsky's version from September 1996. [»] v5.xx motherboards became compatible with Pentagon timings by the end of March 2014. [»]
The Profi extender for Profi v3.x, v4.x, v5.x card -as its name suggests- expands the capabilities of the Profis. The circuit, which is compatible with v3.x, v4.x and v5.x cards, was released in June 2016. The SD card unit is based on the Z-Controller, while the Compact Flash card is controlled by according to the NemoIDE standard on the expansion card. It has 32K cache memory, the #DFFD port mod is also implemented. It is also possible to use as RAM disk the memory above 128K of the total 1 megabyte. Also such modding was made for the Leningrad-2 clone. It is upgrading the Beta-128 interface of v3.x boards to version 4.01. Of course, all motherboard and peripheral board moddings are detailed here, wiring diagrams and firmware alsoccan be downloaded. [»]
Updated July 2022 |
| Himac 44.0x/55.0x
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Integration from Novosibirsk The Novosibirsk Himac Research Ltd. operated from approximately 1989 to 1994. Their first found model is the HRIS, which, contrary to the relevant advertisement text, is unlikely to be a ZX Spectrum clone. Very probably they have first come into contact with the Spectrum while developing the combined Beta-128 controller and LPrint III interface for the Leningrad Neti 212a, which bore the HR23-HR41 model designations. The head of the Himac developments was Kozlov Dmitrij Nikolaevic (Козлов Дмитрий Николаевич aka diman_the_best). [»], [»], [»] The Himac HR42.0x (that is Himac 48K) clones began to be sold in 1992, as bare motherboards and kits. They opened their store in 1993, at which point they also sold complete machines. The clone was originally supposed to be built around the КА1515ХМ1-6003 base matrix crystal (BMC), which was ordered from the Moscow company Form (Форм). The final version, however, used the И185 ULA clone. Unlike the other ULA variants, this implementation was realized with two chips in a dip40 package. The circuit was made at the Experimental Design Bureau of the Novosibirsk Semiconductor Device Plant (Особом конструкторском бюро Новосибирском заводе полупроводниковых приборов). The lead designer was A. E. Vtjurin (A. E. Vtyurin), and the director of the Novosibirsk Faktor (Фактор) technical center, Mikhail Leonidovic Tarasov (Михаил Леонидович Тарасов) also participated in it. Therefore, according to the technical documentation, the HR42.0x was declared to be compatible with the Elite 48K clone produced by Faktor - unfortunately, not much is known about the later 128K Elite version. The 6003-based prototype has faded into oblivion; however, a motherboard with the earlier 1515XM1-216 chip has already surfaced. [»], [»], [»] Returning to the finished Himac, fundamentally it was a single-field 48K compatible machine, with 8 pieces of 565RU5 chips. The 573PФ8 EPROM contained the Turbo-90 and TR-DOS 5.03 or the self-developed HR-DOS 1.043p firmware. The latter is interesting in that, while it included a printer controller, its size was half that of the original TR-DOS. The printing options included single and double-sized graphics, Sinclair and Cyrillic fonts, as well as Draft and NLQ quality printing. The built-in Beta controller could handle two units. The motherboard is compatible with both the AY-3-8910 and AY-3-8912 sound chips. The order of the Din connectors from the edge inward is: DC 5 volts, joystick, RGB, tape, Centronics, then the Neti bus, with the floppy drive on the right and the AY chip output on the left when viewed from the front. Its size is quite compact, 23.5 x 7.5 cm, it most resembles an expansion card. It was a very reliable machine. According to the tests, its speed was 71340 tacts/frame, which is 101.91% of the original 48K Spectrum. Nevertheless, the games Elite and Star Pilot ran slower. [»], [»], [»] The Himac HR55.0x is the 128K version. The motherboard has been restructured, its size is now 17.7x10.6 cm. The order of the DIN connectors has not changed. Next to them are the floppy and Centronics ports. The board now only accepts the AY-3-8910 sound chip. The chipset became the КА1515ХМ1-6004 circuit, it seems that by this time they had already established a closer relationship with the Form company. Thus, this machine is more related to the Narcom clones. Here, HR-DOS already supports the Robotron 6329, CM6312, CM6337, D-100M, and EPSON FX-800 printers as well. By the way, this version was also included in the combined AY-LPrint III interface from Art East Computers. The Last Word II text editor was adapted to the system by Zhuchkov D. (Жучкoв Д.). [»], [»] In addition to TR-DOS 5.03, 5.04E can also be used. [»]
The Limits of Resurrection: the Base Matrix Crystals This time, the resurrection began in the original hometown of the hardware. Vitalij Mihalkov (Виталий Михалков, aka MV1971, tetroid) posted the test motherboard of the HIMAC HR55.02 on the online marketplace in April 2015. A fully assembled working machine most likely does not exist, as the CPLD-based emulation of the 6004 circuit has not been resolved. The HR42 has not even been recreated in the form of an empty motherboard. [»] ↑date: 2024/12 |
199x. 
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199?. 
2015/04. |
| RU-4. Scorpion |
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4.1. Scorpion: the birth of a St Petersburg rival The precursors to the Scorpions' story are Leningrad, Composite (Leningrad+) and the Leningrad 2 machines, developed by Sergej Jurevich Zonov in St. Petersburg. These were simple 48K clones from 1987. The circuit diagrams for the first two models were made available to the public by Zonov, as with the Pentagons, and were very widely cloned due to their simplicity and cheapness. The developer's only request was that, in return for the circuit diagram, each manufacturer should send him back 20 blank motherboards on which he could fit his own components and market them. Spectrum 48, Ural-48K, Vesta IK-30, Electronics KR-005, Kontact , CICH-48, Sunkar, NETI - just a few of the brand names under which the first machines appeared - some from Zonov, others from various electrical engineering factories. The plus model is a bugfixed version of this, which has also been cloned by a company called Composit. It is the brand name on the motherboard that has made its public name - it was perhaps the replica produced in the largest numbers. The second generation is an enhanced version optimized for mass production, with the edge connector and DIN sockets integrated into the motherboard. Zonov founded Scorpion with the intention of creating a more serious clone. Work began in early 1991, starting in Leningrad. Another developer of Scorpion, Andrei Anatolevich Larchenko (Andrew Moa, MOA), met Zonov at a flea market in 1987. He went to work for Piter Ltd in 1990, and first heard about the new prototype while writing the 1991 book ZX Spectrum for users and programmers. The name Scorpion ZS 256 includes the author's initials and the memory size in kilobytes. The first known public motherboard, the SC11, was released in November 1992, and the first advertisements for the machine appeared in January 1993. A variant of the base machine was the Scorpion ZS 256 Turbo, which already ran at twice the processor speed. Issue 3 of ZX-König diskmag [" ] expected this Turbo version to be released in August 1995, but other sources say it was December instead... Although this might be the v2 version, more details a bit later... This was also when the ProfROM add-on was released, which used 128, 256 and 512K ROMs and included built-in (utility) programs and peripheral controllers. Both normal and turbo machines were installed into the remaining desktop cases of Soviet-Russian Corvette computers produced between 1985 and 1992. Unlike the case of Leningrad, the circuit diagrams were secured and the circuit elements were stripped of their inscriptions with sandpaper, making piracy more difficult. The compact size compared to the Russian clones and the resulting dense printed wiring also made copying difficult. Zonov also claimed that the machine use a selt-test routine to check at boot time that the configuration was factory original - a claim that proved to be false, the design is sensitive to only some of the original parts. A year and a half after its release, the wiring diagram was leaked out and this clone was also pirated. The first copies were made in the town of Ufa, 1600 km from Saint Petersburg. In good Russian tradition, pirated versions of the pirated versions appeared... Interesting fact: the quality of these could be superior to the original, but of course they were mostly inferior quality. It is indicative of Russian conditions, that the pirates did not hesitate to include their own copyright inscriptions on the wiring diagrams. Must be tell in their defence, they often made some really noticeable modifications, such as the case of Scorpion ZX-256 pirated clone by V.Y.R. Pirate releases are characterised by the fact that they do not remove the inscriptions from the components and their part insertion order is different from the original. In addition, the colour and lettering of the PCBs also indicating the fact that they are copies. At the same time, as the pirated versions were released, many people rewrote the parts of the original clones themselves. Scorpions were manufactured, advertised, sold, serviced and supported in-house. For example, they introduced the option of ordering through the post and repairs were made at the cost of parts and postage. Faulty machines had to be accompanied by factory documentation to avoid pirated clones being repaired. Since they were fully (or at least 99%) compatible with the original ZX Spectrum 128K against the Pentagon,, the odd situation arose that a similar flame war between Pentagon and Scorpion owners was taking place, as was common among ZX-C64, Amiga-PC-ST fans. With two main novelties it was stand out from the mass clones. One was the 256K of RAM, a giant among ZX machines of the time, whose management scheme was developed in collaboration with Vjacheslav Georgievich Skutin, aka Captain Nemo. This is supported by the fact, that after Nemo left the company, his second clone series, the competing KAY 256 series, produced between 1994 and 1997, had the same memory management. Therefore, this architecture, based on the Leningrad machine, is also known as SKAY by merging the names of the Scorpion and KAY machines. Besides the 256K of RAM, the other plus is the built-in firmware called Shadow Service Monitor, which was released by Larchenko a year after the machine was introduced. The firmware, which can be activated with a button (Magic Button), consists of hardware/software setup, debugger and user programs. The other specifications, however, were reminiscent of the clones of the time. The machine used a simplified version of Beta-128, capable of handling two floppy drives. It included the Sinclair edge connector, a Centronics parallel port and optionally the AY chip could be installed with ACB stereo tuning of course. The size of the base plate is 23.5x16 cm. The processors for the machines were Zilog Z0840004PSC (4 MHz) and Z0840006PSC (6 MHz) - whichever could be obtained according to the shortage economy. The latter were used to make the 7 MHz turbo variant, taking advantage of the legendary factory overclockability of the Z80 processors - not even a heatsink was needed for the factory overclock. The controls for the CPU turbo section were placed on the right mini breadboard on top of the board. The even smaller breadboard on the left is the location for the also optional Beta-turbo controllers. Turboing was initially solved with Russian KP1533 series chips (Scorpion ZS 256 Turbo v1), later with Intel programmable circuits (Scorpion ZS 256 Turbo v2). The latter solution was not only more reliable and reduced the number of components needed, but its burned-in firmware routines also provided better protection against piracy - again, according to Zonov's questionable claim. In addition to the processors, the type of AY-chip varied depending on the available parts, with both the 28 (AY-3-8912) and 40 (AY-3-8910) pin types, the board being designed for the former. If you couldn't afford it, or didn't have an AY-chip, you could upgrade the beeper sound with Covox variants, as with the Pentagons did - the increased processor speed of the turbo machines came handy in this case. The colour of the motherboards (brown, grey, yellow, yellowish-grey, blue) does not represent any evolutionary order, it is also a function of the raw PCB boards that were available in the scarcity economy – so the quality varied greatly. In Russian terms, however, the accurate and consistent marking of the version and publication date of boards is exemplary. Initially, versions and release dates were marked precisely to the day and then to the month (SC11 08. 11. 92, SC12 01. 93, SC13 06. 93 and SC14 08.93). Turbocharged machines were only supplied with the last version of the mainboards, but all Scorpion owners could order a tuning for their existing machine. There was also a pirate edition SC15 08.94, but this should not be confused with the next generation SC15 factory mainboard shown in the next paragraph. The Scorpion ZS 256 Turbo+ was produced from 1996 to 1998, and there are two motherboard versions (v15, i.e. SC15 and v16/SC16). The machine was advertised in issue 3 of the ZX Format disc magazine [" ] (February 1996), the first schematic dated April 1996. The smaller, green-coloured motherboard (21x16 cm) was fitted with a protective mask and manufactured in Finland to modern standards of the time. For the modders' convenience, it also includes a breadboard. This time on the side, which can then be removed, reducing the width to 19,5 cm. The connectors are positioned so that they can be easily inserted in place of the old motherboard. The power consumption of the new board has been reduced from 0.95 to less than 0.9 amps and requires only 5 volts. When used with the more modern 3.5" drives, the 12V voltage was therefore not required. Another new feature is the hardware turbo button (with LED indicator). So you no longer need to call the Service Monitor to switch between normal/turbo mode. Another new feature is the appearance of two ZX Buses on top of the edge connector. Unlike the competing KAY clones, these are of equal priority. An RS-232C connector and a few bugfixes are other new features. Here the chip labels have not been deleted, and a complete circuit diagram has been included with the motherboard. Zonov explained this by saying that anti-piracy protection was solved exclusively by the encrypted routines integrated into the firmware. In this case, the claim may be true - especially considering the fact that the latest firmware, 15.4, which controls the CPU turbocharger, has not been decrypted to date. In the latest batch, this CPU-turbo firmware has been placed into an Altera LC FGPA circuit instead of GAL chips, also from Altera. The Scorpion company also developed a series of add-ons that didn't really became widespread. The Scorpion 2000's planned specification was published in the issues 5-6 of ZX Review (November 1997). [" ] In fact, it would be the ZS 256 Turbo+ motherboard with integrated the most important additions the company had released up to that point. The simpler ones would have included the IBM PC Keyboard and Mouse Controller, the SMUC IDE controller and the 512K ProfROM. The most complicated task was the integration of the GMX card (Graphics Memory eXpander) developed by Larchenko. This would have provided, among other things, a 2048K RAM expansion, 640x200x16C resolution with vertical hardware scrolling and Pentagon compatibility in normal and turbo modes. By Zonov's plan was not only possible to upgrade all Scorpions to 2000, primarily by installing the GMX card, but also to include instructions for the other ex-Soviet clones for updating. The departure of Larchenko, the end of the mainstream Spectrum era and the Russian economic crisis meant that the plans came to nothing - the company's profile became PCs, office equipment and consumer electronics. Official support for Scorpions ceased in 2002. 4.2 The Scorpi was also resurrected... Vorobyov V. A., aka deathsoft from St. Petersburg posted a restored schematic of the Scorpion on the dlcorp.nedopc.com forum in early December 2006. The last known revision of the bugfix, on which he was worked on with the community members, is from the end of November 2012 for the case of Scorpion 256T+ mod.2012 deathsoft. [»] Andrej Gunenko (Black_Cat/ERA Creative Group; Berdsk) has done his own bugfixes based on an earlier version of this circuit, which he posted on the same forum at the end of January 2009. [»] He has also archived the schematic of the Scorpion 256T+ mod.2009 Black_Cat on his own zx.clan.su virtual discussion forum, along with other bugfixed ZX clones and peripherals. [»] On of the hardware constructor of zx.pk.ru, krotan, makes and sells his own versions based on the Black_Cat version, with ongoing bugfixes. [»] Released in January 2009, the Scorpion ZS 256T+ mod.molodcov_alex is the work of Aleksandr Molodcov (molodcov_alex, Molodcov Alex, Kolpino), who we have already met in conjuctions with the reconstruction of the Pentagon board. [»] A few days after its release, it was received a developer bugfix. [»] Based on the drawing that was made public, the forum's hardware people made all sorts of modifications to it, adding their own improvements and bugfixes, and released their own revisions. The first known major bugfix is the work of Pavel Ryabtsov (aka Paul; Kineshma) from June of 2011. [»] His own version was released a few years later, in November 2017. The main new feature of the blue Scorpion 256 Turbo+ mod.2017 Paul motherboard is the integrated ProfROM interface. The black-coloured Scorpion 256 Turbo+ mod.2018 Paul, released in April of the following year, is a bug-fixed version of the previous. [»] The Scorpion 256 Turbo+ mod.2019 Paul was released at the end of July the following year. [»] The latest reincarnation of Scorpion is the work of Roman Boykov (aka romychs) from the Russian capital. The machine, based on Pavel Ryabtsov's circuit diagram, was unveiled at the end of January 2021. [»] In addition to optimizing the wiring of the PCB, the edge connector has been also removed. In its creation, it also drew inspiration from the soon-to-be-unveiled 1024 Scorpion. He also made the documentation public His GitHub repo. [»]In November, it received a community Beta bugfix based on a comment from Dzerzhinsk by forum member tigr101274. This changed the name from Scorpion 256 Turbo+ v16.1 mod.2021 romychs to Scorpion 256 Turbo+ v16.2 mod.2021 romychs. Minor bugfixes have been going on since then. . The original Scorpion ZS 1024 Turbo+ motherboard was created by Vjacheslav Valerevich Savenkov (aka Savelij, Savelij13; Sukhinichi). We have also read about the NedoPC team's hardwareman connecting to designing the ZX Evolution clone. The motherboard posted on the aforementioned forum has already received substantial improvements. As the motherboard evolves, versions, dates, and creators are in turmoil, so once again it's essential to unify the names. The first version of the Scorpion 1024K Turbo+ v17 mod.2011 Savelij, released in September 2011. In this one, the A RU7 chips have been completely removed, replaced by a single 1 megabyte SIMM module. Memory management on the new motherboard can be jumpered between Scorpion ZS 256/1024 and Pentagon 512 modes. The 1 megabyte memory addressing is based on the KAY-1024/3SL/Turbo clone scheme introduced in 1997, which can be traced back to the Profi clones. The ProfROM expansion is also integrated and supports the AY-3-8910 chip with a dedicated audio output connector. The size of the board is 22.5x16.5 cm. [""] The original wiring diagram for the 1 megabyte SIM module is from the Deja Vu #0A magazine, September 2000, by Denis Ivanovich Latyshev (Cardinal/Playgear Company; Kemerovo). [»] The circuit, by the way, is an un-bugged version of the circuit published in the May 2000 ZX Light #0C diskmag. It's the work of Novosibirsk's Konstantin Chichkanev (Eraser) and Artyom Sergeevich Larin (Timon). [»] The Scorpion 1024K Turbo+ v18 mod.2012 Savelij motherboard was released in March 2012. It was new with the option to disable port #1FFD and the banishment of serial port related components. Also integrated was the video output tuning from Deathsoft in St. Petersburg. [»] The #1FFD block hack is originally a modding by Vladimir Larkov and Dmitrij Petrov from 1993/94. It consists of disabling the port in question with a switch. It is responsible for handling the expanded 256K memory and copying the contents of ROM to RAM. It also activates the Service Monitor on later Scorpios. The wiring diagram was published in ZX Format#01 in October 1995. The authors have given permission for the article to be freely redistributed, allowing more and more Scorpion owners to make this modification, which greatly increases Pentagon 128 compatibility. [»] The production of the Scorpion 1024K Turbo+ v19 mod.2013 Savelij motherboard was undertaken by Alexander Korovnikov (Zorel) from Dnipropetrovsk. He ordered the hardware from the manufacturer in November 2012 and the board was released early the following year. He seems to be aware of the lead times of Chinese manufacturers, as you can see he marks this and subsequent motherboards with the year of their expected arrival. He became the main designer after this board, so the following boards will bear his nickname. There are now four ZX Buses on the last Savelij clone, which has now grown to 22.5x20.2 cm. The designer has also integrated VGA and PAL connectors, as well as an RGB encoder. The Magic and reset buttons have separate pins. The ATX connector has been introduced, the power supply is based on the ZXMPhoenix scheme. The mounting holes on the motherboard have been made larger and the jumpers have been labelled. The Beta-128 power supply has also been improved. [»] June 2015 marks the release of the next revision, Scorpion 1024K Turbo+ v20 mod.2015 Zorel. This was a new with the ATX standard motherboard and USB keyboard connection. The power supply circuitry is a clone of the KAY-2010 - for cost optimization. This board is unfortunately buggy, a bugfix is required if the original keyboard controller must be used. [»] Korovnikov ordered the Scorpion 1024K Turbo+ v21 mod.2016 Zorel card from China before Christmas 2015, this time without any community pre-financing. This is a bugfixed revision of the previous version. In May, forum members were able to install the new motherboard. [»] Last but not least worth mentioning is the Pentagon 128K 2+ ATM timings for Scorpion ZS 256 Turbo+ mod from April 2019. Sergey Andreevich Smirnov (Gogin, SMIR, Hacker SMIR, Cherepovets) tunes his Scorpion to the classic Pentagon timings using seven chips. [»] Updated: 2022. May |
| RU-5. ATM Turbo |
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5.1. ATM machines in the 1990s The ATM Turbo is an 8-bit microcomputer series. As it offers many innovations in addition to ZX Spectrum compatibility, it cannot be called a simple clone. Rather, it is a unique computer architecture with both ZX and CP/M modes. And the third, native ATM Turbo mode is roughly equivalent to an EGA Turbo XT. The Moscow-based MicroART (µART) and the ATM (Association of Technology and Microelectronics, formerly: Associaciya Tvorcheskoy Molodezhi - Association of Creative Youth), already been introduced with the associations of the classic Pentagons. The machine they designed, the Pentagon 128K 2+, became the most widely used ZX Spectrum clone from 1991. The creation of the ATM Turbo machines was prompted by the failure to control piracy, as many other manufacturers offering various Pentagon replicas. On the other hand, they wanted to create a more serious, business-oriented machine, an alternative to PCs, similar to the Scorpion and the Profi. Thanks to the rather high price and compatibility issues, they have not been widespread. The machine's motherboard was complex enough to prevent others copying it illegally, mainly because of the numerous innovations in the video controller, of which firmware was encrypted. So, despite the impressive innovations, the breakthrough success was still not achieved. The rather high price, the 5-10 months' average of Russian salary not need to be explained, but the problem of compatibility may be more interesting - if one is not already familiar with the relevant part of the history of ex-Soviet computing, i.e. the first chapter about the Pentagon. The compatibility bug in the Pentagons they had designed themselves was corrected (the memory management on the ATM Turbo was made fully ZX Spectrum 128K compliant), but it was also became one of the machine's downfalls. By the time they were released, the Pentagon 2+ ATM timing had become the de facto standard. Thus the machine did not run the new-age ex-Soviet programs perfectly - several manufacturers, including the aforementioned GRM, Solon and Scorpion, also made this 'mistake'. Despite this, ATM machines were considered by their users - and those who only dreamed about them - to be the best ZX clones. On the one hand, it is fully Spectrum 128K compatible (running classic programs), and on the other, the Beta-128 interface means, that using the new Russian programs is no problem (of course, this requires a hardware patch or making the programs in question ZX128/P128 2+ compatible - this is especially true for the first generation Turbo 1 machines). And the CP/M mode allows you to run a wide range of user programs. The number of programs using the native ATM Turbo mode is probably in the order of 100, and there are games, demos and diskmags that use some of the extra features of the machine. Of course, thanks to the support community, the number of these programs are growing with time. And now back to the hardware! Development began in early 1991 and in November 1992 the ATM Turbo 1 type, then called ATM 512K, made its debut. Its motherboards were numbered from 4.05 to 5.20. The v4.05 and 4.10 motherboards were quite buggy. Also version 4.20, for example, you couldn't add an ADC (analog-to-digital converter). From 4.40 onwards, it was considered relatively bug-free, but it still needed patching to run CP/M, as in previous versions. Version 4.50 was already completely bugfree. This one used the 1556HL8 PAL encoder in a DIP24 socket. The size of these boards was 31,6x13,2 cm. The rarest version, v5.20, was based on the previous one, but supported the 64-key extended ZX Spectrum keyboard and all connectors were soldered to the motherboard. The board was designed to fit into a Russian microcomputer chassis of the Mikrósha brand, which was produced until 1990, and the possible insertion of micro-switches on the motherboard was prepared for this The Z80 processors on all boards run at 3.5 or 7 MHz in turbo mode, with ROMs ranging from 64 to 128K. The RAM size can be from 128K to 512K in standard configuration. Even Turbo 1 offered three graphical modes. The first is of course the standard ZX Spectrum screen. The second is the 320x200 EGA level, 16C mode. That is, for each pixel individually we can choose any of 16 colors from the palette of 64. The 16C actually covers 15 colours, as in the case of Pentagon 1024SL 2.x machines, since the normal and bright shades of black are the same. The high-res mode uses a 640x200 resolution with attribute grid of 1x8 size, so we're talking hardware multicolour - although not with standard ZX Spectrum resolution here either, again more like the EGA. The picture is received via a SECAM decoder on a colour TV or monitor. In addition to the Beta-128, the mass storage can also be a cassette. For sound, there is a choice of beeper, stereo AY-3-8912 or Covox. It also includes a 2x1 watt stereo amplifier. The Analog-to-Digital Converter here is 1-channel and capable of sampling up to 9KHz. The modem is based on this A/D converter. In terms of connectors, there are two Sinclair joysticks and Centronics connector. The Pentagon compatibility of the first version is about 60%, with some modding it is between 90-95%, which is perfectly acceptable. A 48K/128K BASIC printer driver has been added to the built-in firmware. TR-DOS version 5.03 has also been extended. Here, CP/M v2.2 can run on top of a BIOS version 1.03 or 1.04. In October 1992, a new model, the ATM Turbo 2 was announced. The second series, which debuted with version number 6.00, was released in mid-March 1993. Very little is known about it, except that it contained a lot of bugs, and that the IDE controller appeared on this motherboard. In 6.10, which was never made into production, the number of bugs has been reduced, and this can be corrected with about 30 wires. In order to use an XT keyboard with it, the 555TM2 chip had to be added. At this point there was a disagreement between MicroART and ATM. After ATM released its own version 6.15 machine at the end of June, which example had a different ROM (containing CP/M instead of the adopted version of MSX-DOS), then stopped the production. On this machine, the (c)MikroART inscription was removed from the board. In the meantime, MikroART continued the development and production of ATM Turbo 2 with ongoing bugfixes. 6.25 (aka 6.2A) fixed three bugs compared to 6.10. In addition, not only the expensive AY-3-8912 but also the cheaper AY-3-8910 sound chip can now be used. Only two bugs remain in 6.30, which can be fixed with three wires and does not require the 555TM2 modding to use the XT keyboard. In 6.40, the previous bugs have been fixed and the Sinclair joystick and IBM keyboard can be used in parallel. The 64-key keyboard control unit has been removed from the board, although its use is still supported via an expansion card. In ATM Turbo 2, the range of screen modes has been extended with the 80x25, 16-colour text mode. The Secam decoder has been removed, so version 6 machines will not work with TV. The still single channel A/D converter now supports sampling rates up to 20KHz. The CP/M version number remains the same, but it is now running on BIOS version 1.06 or 1.07.12. It is also possible to use the TBIOS operating system. Naturally, the size of the board has also been increased to 33.5x19 cm, and Pentagon compatibility has been improved. The latter is now 90% by default and 95-96% with modding. The 7.00 ATM Turbo 2+ motherboard was released with two bugs at the end of October 1993. From here, in addition to the XT keyboard, you can now use an AT keyboard controlled by the 1816ВЕ31 chip (i8031 compatible). You can switch between the two by swapping ROMs. The memory can be upgraded to 1 megabyte, the same upgrade option for older machines has also been introduced. The modem, which was built from a number of analogue components, has been replaced by a dedicated 8-channel ADC chip (561KP2), the sampling rate has not changed. The reliability of memory and disk management was also improved. The version released in June 1994 saw the return of the Secam decoder. In version 7.10, the previous bugs have been fixed, the keyboard connector has been made more compact, and the PCB design has been slightly modified. An RS-232 serial port has been added, to which a (non-Kempston compatible) mouse can be connected. 5.2. Termination... and resurrection Production was cut back in 1995-96 due to the rise of the Dendy console (a clone of the 8-bit NES) and the PC, and ceased in 1997. Support continued between 1998 and 1999, before discontinued completely. From Klaipeda in Lithuania, Timonin Maksim Anatolevich, aka Maksagor, enrolled to Moscow State University in 1997, when he got in touch with MicroART and the local Spectrumists. Among Speccy fans, he met Roman Valerevich Chunin (CHRV) and Vladimir Karpenko (cr0acker). Who were chatting about the Sprinter clone with Aleksandr Anatolevich Shabarshin (Shaos) and Aleksandr Samsonov (MacBuster). Thus, the NedoPC team was formed in early 2002. At the same time, Maksagor launched the ATM-turbo 1,2,2+ Official support site, at this point on the narod.ru server, which later moved to nedopc.com. Here he published the documentation he had received from MicroART, who fortunately did not denied publishing it after the commercial distribution and support had ceased. CHRV and cr0acker used this documentation to create the first generation v7.10 board of the modern era, which was released in October 2004 to 26 customers. This is the yellow motherboard, of which the green is the later, bugfixed version. The release date for the latter is presumably June of the next year. It contained 15 minor and major bugfixes and was released in about twice as many copies as the previous one. Even this one was not fully bug-free. Fortunately, for both versions, detailed instructions can be downloaded from the website, on what and where to modify for perfect operation. The aim was to make the classic motherboard which is easy to use with the contemporary modern peripherals (keyboard, mouse, HDD...). It was a great help from the team, that the in Russian and international types of parts both were also indicated in the documentation. This may be useful for those, who bought the parts as a DIY kit rather than assembled. It was replaced by the ZX Evolution in 2009, but the 7.10 motherboard remained on offer until 2017. At the same time, Maksagor added ZXEvo to the list of supported platforms. 5.3. Machines of the Internet age As we continue to tell the story, it is inevitable again to re-standardise the nomenclature. So the machines are described as the following scheme: machine name, version, mod.year and developer nickname. Since Maksagor counts Turbo 3 machines from version 8.00, constructed by Zorel, this is taken as the reference - the author himself only refers to it by the version number+year combo. Others have called it ZXEvo, while eXzmos, to be mentioned later, has called the next future generation to be constructed by himself Turbo 3. For a short time, the post-NedoPC variant versions were called Turbo 2++ on the Czech Wikipedia page. In January 2010, Pavel Ryabtsov (aka Paul - Kineshma), the owner of the now suspended Chipkin.ru on-line electronics shop, came up with the ATM Turbo 2+ v7.10 mod.2010 paul replica board. After a gap of five years, in October of 2017 saw the birth of the red ATM Turbo 2+ v7.10 mod.2017 paul motherboard. Its novelty is the possibility to solder both DIN and PS/2 keyboard connectors to the motherboard. Its successor was released in April 2018 in black colour. The ATM Turbo 2+ v7.10 mod.2018 paul motherboard received community bugfixes from the hardware folks at the zx.pk.ru forum. After everyone ordered the now hard to get 1556HL8 EEPROM for these virtual marketplace boards, the ATM Turbo 2+ v7.11 mod.2020 paul was born. Here, the GAL16V8 or ATF16V8 electrically erasable chips replaced the antique, original piece. The matching firmware was released by Alex Shiloff (Tyumen) in February 2021. Also based on version 7.10, Birden from Novosibirsk created ATM Turbo 2+ v7.15 mod.2011 Birden in May 2011, which was presented on the zx.pk.ru forum. It included all NedoPC bugfixes. In addition, it replaced a good part of the components with SMD, the connectors with more standard pieces and some optimization of the wiring. The main innovation is the doubling of the RAM size, achieved simply by doubling the number of the controlling and RAM chips. Thus, the RAM was implemented by using 32 565RU7 chips. In October 2013, Alexander Korovnikov (Zorel) from Dnipropetrovsk presented his ATM Turbo 2+ v7.18 mod.2013 Zorel development on the above mentioned forum.
Also in March 2017, Zorel presented the ATM Turbo 3 v8.00 mod.2017 Zorel motherboard. This is an evolution of the 7.xx versions on ATX standard PCBs, but built with classic components from the era. It works with both AT and ATX power supplies. The first schematics still show version 7.20.
Zorel came up with the idea of 8.10 in November 2018 through community funding. This is a bugfixed version of the previous 8.00 motherboard, for which was also helped the zx.pk.ru forum to find bugs. Maksagor collected these bugs on his website, but Zorel mysteriously disappeared from the forum. His last post was from the end of 2019. The 8.10 motherboard was therefore created by eXzmos from Taganrog, who came up with the idea in February 2021. He also took on the creation of a new generation ATM Turbo motherboard. Vitalij Mihalkov (MV1971, tetroid; Novosibirsk) re-launched ATM Turbo 2+ v7.18 in his usual tetroid red colour in June 2021. Frissítve: 2022. március |
| KAY |
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A rival's rival with a new standart Vjacheslav Georgievich Skutin, aka Captain Nemo, is the founder of the Nemo company in St Petersburg. He was worked with Sergej Zonov for a while, then set up his own company, of course with the aim of creating another ZX Spectrum clone. The design concept is to build a ZX Spectrum 128K clone based on the Composit (Leningrad+) computer, which has the best price/performance ratio on the market, but is also reliable and has open standard. The former was achieved by optimizing the manufacturing technology. In parallel, for expandability, he was began to develop his own standard bus system, the Nemo bus, also known as the ZX-Bus, which has since become the standard for ex-Soviet ZX Spectrum clones. Of course, it was undergone some version changes over the years. He was also worked as a journalist. In the print media, he published in Radioljubitel newspaper until July 2002, when the Spectrum section of the magazine was discontinued. In addition, readers could encounter his writings in the Spectrum fanzine Abzac. Among the disc magazines, he was featured in ZX Format [»]. He also ran his own medium called Open Letters [»]. Here he replied to letters to his company as an FAQ. This could be regard as a further development of the former NemoFAQ disc publication [»]. The first machine was the Composite 128K AY, or KAY 128. Rumours say it has that the origin of the name KAY is derived from the merging of the last three letters of the previous name. Practically, the Composit 48K clone has been extended to 128K, an AY-chip added and the video output improved with RGB and black and white composite outputs. The memory expansion was soldered on top of the original RU5 RAM chips using the same type of chips. The idea is probably based on the schematics of Vladimir Mihajlovic Getmanec (Владимир Михайлович Гетманец, VMG, V.M.G.) from 1991. And the AY chip was placed onto the breadboard on the left side of the 20.5x12.5 cm board. There have been at least two revisions of the motherboard (December 1992 and May 1993). On the first, the upper breadboard is continuous. On the second, it is split into three parts: the connectors on each side, with the optional ZX-Bus in between them. The boards are labelled ZX-COMP 128K and COMP-128+. Due to the inevitable standardisation of nomenclature, they are given the names KAY 128 and KAY 128/SL1. The KAY 128 architecture was introduced in the 1993/11 issue of Radioljubitel [»], the ZX-Bus in the first issue of the following year. [»] These clones can be considered as public beta versions. On those machines, where the expansion port was not yet present, only on the breadboard, the Beta-128 interface could be soldered to the appropriate locations on the motherboard. The KAY 128 used a maximum only one slot, obviously for the Beta-128 interface, which was turbocharged from the start, but only supported two disk units. By replacing the original Beta-128 components, it became more reliable than the original, and the drives became quieter due to the increased positioning speed. In 1994, the KAY 256 clone was released as a rival to the Scorpion ZS-256, and the memory layout was largely compatible with it. Slightly lower price, slightly better quality and, in the case of turbo machines, higher speed... A total of five versions of the 18.5x17.5 cm motherboard had been released until December 1997. Nemo dropped the Composite designation altogether at this point and began to versioning the motherboards. The KAY 256 machines were introduced in Radioljubitel magazine issues 11, 12/1994 [»] , [»] and 1/1995. The other Spectrum-developers could see the machine at the Spectrum-compatible computers manufacturers' conference in December 1994. [»] In addition, the NemoFDD floppy disk controller was published in Radio Amateur magazine 3/1995 [»], and the PC/XT keyboard controller using the Profi clone firmware was published in issue 5 of the same year [»]. The turbo version was released in the October 1995 issue of the ZX Format#01 floppy disk magazine. [»] The NemoIDE controller responsible for controlling the IDE hard disk was based on a nearly forgotten prototype by Nikolaj Tyrsin in 1994. Tyrsin and Nemo dusted off the schematic and launched the product in May-June 1996. It was featured in issue 5 of ZX Format in December 1996. [»] As with many other Russian clones, the motherboard is again designed for the defunct Corvette computer's desktop chassis. Servicing was done in the price of parts, just like the Scorpions. The machines could be purchased from the manufacturer, a St Petersburg company Logros, and from 'regional dealers' in the markets. Postal parcel delivery was of course limited to parts, as it was not worth sending less than three complete machine by post. Versions 1.0 and 1.1 still had two expansion ports (KAY 256/SL2) in 1994 and 1995. The 1.2 to 1.4 versions produced between 1995 and 1997 had three (KAY 256/SL3).The 1.4, the last version of this series, has also turbo mode – the CPU, RAM, ROM, IDE and Beta-128 and ports all had turbo - i.e. full-travel turbo mode was implemented (KAY 256Turbo/SL3). Unlike at Scorpion, these have different priorities, the highest being the first slot, and the lowest being the last. The PCB is the work of Kuzmin Viktor Anatolevich (KVA), from the city of Grodno. The machines are implemented using discrete circuits, i.e. no programmable logic chips like the Scorpion. Nemo says, it's the motherboard schematics that should prevent piracy, not the chips and firmware that make the protection effective - and time has proved him right. Not incidentally, Spectrum fans consider it the most sophisticated clone, so the design was truly a masterpiece. In its day, it was a benchmark in terms of price, quality and performance. Unlike other clone manufacturers, Nemo did not risk using aftermarket Z80 clones and overclocks, but used original 8 or 10 MHz processors even for non-turbo machines. The machines came from the factory with the Beta-128 controller, the AY-chip was optional. Reportedly they have 95-97% ZX Spectrum compatibility. Of course, there were problems with software optimized for the 1991 ATM Pentagon, especially in case of demos. In terms of connectors, this is where the Kempston and optional Sinclair 1 and 2 connectors appear. There is also a Centronics port in addition to the video outputs mentioned earlier. Other than the slots, this two-way Centronics was also intended as an expansion port, but was not used for anything other than connecting printers, although its possibilities were mentioned several times in the articles. As the part of the original concept, the cassette unit socket was also added to the board. The KAY 1024T/SL3 was first described in the issue 8 of ZX Format diskmag (December 1997). [»] The version 1.5 motherboard contains one more IC than its predecessor. This allowed to be a drop-in-replacement, as the size and screw locations were the same. The Nemo bus has been solved here with the connectors used for the ISA to keep costs under control. The centre-to-centre distance of the pins has been increased to 2.54 mm from 2.5 mm, so care must be taken when inserting some cards. The efficiency of turbo mode has been improved, but it can't be turned off for the processor. In addition to being the proud owner of the fastest turbo clone title, it became incompatible with many games and demos. Port turbocharging was disabled. Compatibility is 97% according to Nemo. The RAM can be used in two ways: full 1024K or 256K+RAMdisk. The firmware and memory management is from the 1024K Profi clone. The firmware update was initially done by Nemo, then taken over by Aleksej Voskresenskij (Las, Las Jackwolf; St. Petersburg). Since the last classic KAY 1024 (and thus the last classic ZX Spectrum clone) was bought in 2001 by Evgeny Ilyasov of Balashov, the classic machine with the 2002 Las firmware never saw commercial release - but was available for the later clones [»]. Nemo announced in issue 16 of Abzac magazine (May 2003) that if he didn't get 30-50 orders, he would close the company. And he didn't get…[»] This time the constructor is also involved in the resurrection The first bug-fixed version of the classic KAY 1024 Turbo 3SL card was created by Andrej Gunenko (Black_Cat/ERA Creative Group; Berdsk). Along with other clones and peripherals, he has posted the improved 2008 wiring diagram on his forum. [»] As much as Nemo argued against networks in the classical era, it may seems surprising that he found the zx-pk.ru forum with the idea of community bugfix and production - but the truth is, he had no other choice if he wanted to gain wide support... Here registered in early 2009 from the city of Kamyshin. In April 2010, he came up with the idea of debugging and producing the KAY 1024 Turbo/SL3 mainboard. [»] Then in September, he started to develop it further with the KAY 1024 Turbo/SL4 board together with the forum members. [»] The KAY 1024Turbo/SL3 mod.2010 lyaMIV was released in June 2010 by a fellow forum member lyaMIV from Kursk. [»] The matching floppy disk controller was released in the same month, and got a bugfix right away. [»] The motherboard itself was 'finally' bugfixed early next month, by Nemo and the forum members... [»] Pavel Rjabcov (Paul; Kineshma) created and released his own version of the board years later, in July of 2017, based on these bugfixes and the Black_Cat version. Pavel's red KAY 1024 Turbo 3SL mod.2017 Paul PCB had its parts labeled and a matching floppy and IDE driver was released. [»] On this mainboard tigr101274 made some new bugfixes in December. The KAY 1024Turbo/SL3 mod.2017 tigr101274 card is occasionally available in the meshok virtual shop of the colleague from Dzerzhinsk. [»] As far as the hardware is concerned, as mentioned, the NemoFDC floppy controller was introduced here, and was inherited by the next 4-slot machine. The NemoIDE card, on the other hand, was born with the 4 slots machine will be mentioned in the next paragraph, so Paul 'arbitrarily' added it to the 3 slots board. The same is true for tigr101274's configuration. The IDE controller also received a bugfix in January 2018 from Feliks Knjazev (aka SoftFelix, St. Petersburg) [»] Nemo, as was mentioned before, announced the KAY 1024Turbo/SL4 as the successor to the classic-era clone in a topic started in September 2010. At the same time, the NemoFDC floppy controller and NemoIDE cards in matching blue colours were also introduced. These were manufactured by Sabirzhanov Vadim Mirzhanovich (zst) from Chelyabinsk. There are two versions of the motherboard. The first one is called 'Old' (October 2010), while the new one is called 'Fixed' and 'Final' (February 2011). So, according to the nomenclature so far, we can talk about KAY 1024Turbo/SL4 mod.2010 Alex_NEMO and KAY 1024Turbo/SL4 mod.2011 Alex_NEMO. The 22.7x21.7 cm motherboard, which is the result of community development, has introduced a number of innovations. First, the fourth Nemo slot, which proved unstable when cold and in turbo mode. On the other hand, has a single SIMM30 slot in addition to the traditional memory. This allows a single module to use to expand the RAM to 1 megabyte. In the classical era, he was against both solutions. In his opinion, the fourth slot is too much for the architecture, the SIMM module is more unreliable and more vulnerable than the ones soldered to the motherboard. The former claim has been proven in practice, the latter one... Let's see what new features it offers compared to its predecessor. AY output is now available in ABC/ACB stereo modes. PS2 and ATX connectors are ensuring PC-compatible connectivity. Furthermore, power supply solutions have been improved. SoftFelix also developed a 2 and then 4 megabyte memory extension in April 2011. At the same time, the firmware's memory management was made compatible with Pentagon/Profi 1024 and ZXM-Phoenix 2048 clones. Alexander Korovnikov (aka Zorel - Dnipropetrovsk) released a bugfix in July 2015. The KAY 1024Turbo/SL4 mod.2015 Zorel mainly fixes the bug that the original motherboard blocks memory above 128K immediately after power on. [»] Soon the matching NemoFDC and NemoIDE cards were also released. Paul has made his motherboard and accessories based on this in two series. Paul gave away the first series of red KAY 1024Turbo/SL4 mod.2017 boards, as it was missed the labelling of the parts and the solder mask on the backplate. The series received another bugfix the following May and the black KAY 1024Turbo/SL4 mod.2018 Paul was released. This eliminated the bug where the completely unnecessary VD2 diode would blow out on the first press of reset. Also redesigned the board slightly for easier installation. [»] The little brother KAY 256 has also been resurrected. The Kurgan-based gdv2002 came out in September 2021 with the KAY 256Turbo/SL3 machine, a replica of the v1.4 board. A few days later, Mihail Tarasov (Mick or Micklab) from Kaluga published the schematic of the very first v1.0 KAY 256/SL2 version. [»] When finished, he also converted gdv2002's work to P-CAD 2002 format. [»] Based on version 1.4, the KAY 256Turbo/SL3 mod.2021 gdv2002 was developed, starting at the end of November 2021 and was completely bug-free by April in the following year, thanks to the suggestions from forum members. The kit includes the NemoFDC and NemoIDE as well as the NemoBUS extender card. The two NemoBUS connectors have been removed from the motherboard and replaced by a 64-pin connector row. This allows the three-slot extender to be connected. Another change is that the board can accept 27512 (64K) or 29C040 (512K) EPROMs. The AY-out can be switched between ABC and ACB stereo. The outputs of the motherboard are VGA; audio out and cassette unit via 3.5 jack; Centronics; and two fire button Kempston joystick ports. Thanks to the 21 x 13.5 cm size, it can be easily installed into the rubber-buttoned Spectrums or into the Robik clone's chassis. [»] ↑date: 2024/12 |
| Compact (Compact)
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A hybrid of Pentagon, KAY, and Scorpion The Compact computers were made by the T.V.S company in St. Petersburg. There are two known versions of the clone, the Compact 128K and the Compact 256K Turbo. The interesting thing about this computer is, that it combines features from several clones. On one hand, it follows the building principle of the Pentagon 128K 2+. So, alongside the computer, the Beta-128 controller is easily distinguishable. The size of the motherboard is quite 'compact' compared to the Pentagon 128K. Despite the similarity to the Pentagon in terms of shape, the circuit and the schematic of the Beta-128 controller resembles the KAY clones. According to sources, the clock generator of the KAY-128 comes from the Compact, [»], and the connection diagram of the 256 Compact featured the text KAY-256 [»] So, Nemo and the developers of the Compact definitely collaborated. To top it off, the 256K version uses the Scorpion ZS 256K firmware, and both versions include the Scorpi's Magic Button. And as if that wasn't enough, the timing of the processor and AY chip of the 256K version is compatible with the of КА1515ХМ1-based clones. Let's first go through the common characteristics of the Compact computers! The 28x13 cm-sized motherboards contain only DIP circuits with through-hole technology. They are built from reliable, easily accessible components into boards, which match in their concept but differing in details. The motherboard operates at 5V voltage. The Beta-128 is made with digital PLL circuits and can operate at turbo speeds. Its components allow for more reliable operation and the use of lower quality drives. The 12 volts necessary for operating the controller is provided through a DC/DC converter. There is an expansion connector between the computer and the disk controller - again a quite unique solution. With this, a new expansion slot standard has appeared, which is the Compact-bus. It is compatible with both the AY-3-8910 and the AY-3-8912 sound chips. Using the parallel port of the former, we got a Centronics-compatible printer connector, which is controlled through the 251 port. This is not very compatible, as it uses a simplified decoding scheme [»] They also have a Kempston joystick interface, Sinclair is emulated through the keyboard. It has a built-in mono AY beeper amplifier and AY stereo line-out. They have improved RGB outputs, from which was converted the black-and-white composite picture. The keyboard is buffered. Despite the built-in floppy controller, the cassette unit input and output are still present. The Reset and Magic Button jumpers are also available here, the latter being implemented in a rather buggy manner. The realization of port 255 (#FF) is missing, but this generally does not pose a problem, they are considered one of the most compatible clones. The first version, the Compact 128K, was released in early 1993. This one has 128K of RAM and a 3.5MHz processor. Similar to the Pentagon 128K, it uses 3 slots, so 48K from the 64K capacity ROM. The enhanced version is the Compact 256K Turbo. In this one, the Z80H processor operates at 4/8 MHz. It also uses the Scorpion's Service Monitor (2.7b, yellow Scorpion firmware set). The AY chip works at 2 MHz instead of the standard 1.75 MHz. By changing the 16 MHz clock quartz to 14 MHz, the operation frequencies of the CPU and sound chip become standard. The RAM-memories are 32K RU7 chips, and the machine is not very sensitive to their quality. The date of the found motherboard is July 1994.
New machines and peripherals for compatibility The recreation began on the initiative of vidic_ks03 (Noyabrsk). The developer came into contact with the machines beetwen 1993 to 1995. With the recreation, he wanted to preserve the memory of this rare clone for posterity. Therefore, he did not recommend any changes other than replacing the printer and FDD edge connectors with pin type ones. The creator of most community bugfixes is from Saki, who has the rather interesting nick (--). Thus, the first version of the remake was born by the end of October 2017. [»] Pavel Rjabcov (Paul, Kineshma) ordered the first series from China, for which the community was chosen the red colour. To facilitate assembly, s sergey from Stolbovaya was opened a dedicated topic. [»] The wiring diagram for version 1.1 was completed by February 2019. [»] In addition to Paul's blue series, Aleksandr Samsonov (aka MacBuster) from the capital also ordered a batch for the members. The initiator vidic_ks03 also published his plans for version 2.0. The community added its own ideas to it, but the initiative was abandoned... [»], [»] Roman Boykov (Romych) from Balasiha started bugfixing the motherboard from August 2020, which became version 1.1r. Hans Meier (aka Shockwav3) from Berlin also constructed three expansion cards for the clone, which make operation more compatible. After making separate prefboard prototypes The first includes a ProfROM 4.01 hw emulator, #FF port implementation, Scorpion-style turboswitch (with microswitch or controlled via #1FFD, #7FFD ports) with a Molex power connector. [»]
The second is a Nemo/Scorpion bus compatible connector with standard #FB port decoding and Covox driver.
Finally, the third is used to set the Scorpion compatible value of the INT signal. [»]
In April 2021, the first member of the 1.1x series, 1.12 from Krasnoyarsk, was released. [»] It was created by Ser, who was integrated a VGA and PAL converter and a PAM8403 type 2x3W amplifier onto the motherboard based on version 1.1r. This was followed by versions 1.13 Ser was also created the #FF port auxiliary circuit for version 1.2r. [»] Almost certainly, this is based on Hans Meier's wiring diagram.
↑date: 2024/12 | |||||||||||
| ZX-777 (ZX-777)
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Pentagon specifications on Leningrad basis The ZX-777 was a clone produced by the Elekon company from 1993 in Saint Petersburg. It is considered an expanded Leningrad, for which made the TV output standard and added the standard expansions at that time. These include the 128K RAM, the AY-chip, as well the Beta-128 and ZX-Lprint III interfaces. Perhaps this is where the alternative Pentagon-777 name is stuck - although only the expansions came from the Pentagon 128K 2+ ATM, the basic construction is Leningrad. The logo of the machine is a dice with sevens on three sides, here is where the name comes from. Due to the simplified Beta-128 controller, it was advisable to use high quality floppy disks. It is also worth mentioning, that both AY-3-8912 and AY-3-8910 are supported. The motherboard size is 23x16 cm. The machine has two extension slots, that correspond to the peripheral connectors. These are video and audio outputs, cassette unit connectors, Kempston/Sinclair Joystick ports, and parallel printer port. It had non-standart timing and was supported the use of the 56-button extended keyboard. The inscriptions 06KEEN93, 08KEEN93, 11KEEN93, 01KEEN94 on the motherboards indicate the year and month of design or production. The 5.03 TR-DOS version was later replaced by 5.04T.
Remake for MicroATX case Mihail Tarasov ( Mick ) from Kaluga wanted to create a board close to the original specifications in early 2020, based on 01KEEN94. It was his first ZX Spectrum clone with disc unit. At first, he loaded the photos of the PCB into the SprintLayout program, then converted it with CAM 350 software into P-CAD 2002, then followed the virtual implantation of the parts. The 16 pieces of KR565RU5G chips were replaced by four LH2464-12 DRAMs (Toshiba). In addition, after correcting the timings and Beta-128 to the standarts, the ZX-777 03Mick20 revision was born, the February 2020 version. Of course, this is only the P-CAD 2002 circuit diagram, the yellow white labeling motherboard was ready by the end of July. [»] In March, the idea of construction of the ZX-777 Extender Board was raised, which was completed by August. [»] This can be connected to the machine through the two slot system buses and offers standard connectors. Thus, a parallel Printer port, Atari-compatible Kempston/Sinclair, floppy drive connector, VGA video, jack cassette unit and sound out as well keyboard interface were also integrated on the 23x9.8 cm board, which is seamlessly fits to the motherboard. The ATmega48 AVR RISC microcontroller contains the keyboard firmware from Kamil Karimov (Caro). And into the Attiny15 microcontroller included the ATX power control codes, which Mick borrowed from his own ZXM-Phoenix machine. After the bugfixes of the motherboard, and writing the firmwares of the extender, the complete new clone, from the unification of the two boards, became operational by September. [»] Best of all is that an old-new clone can be installed into a standart microATX case, which he was also announced on the TS-Labs forum [»], as well as on his vk.com page. [»] and [»]. As usual, Mick also archived the project on his own website. [»] You could order the boards from the constructor in the virtual market of zx-pk.com. [»] ↑date: 2024/12
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1993/11., 1994/01. 
2020/07-08. |
| Narkom 128K (Нарком 128K)
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Two machines with a common circuit diagram The Narkom (Нарком) 128K clones are machines from the Moscow-based Form Co. Ltd. (НПФ "Фopm"), which are built around two logic base matrix crystals, the КА1515ХМ1-6006 and 6108, and which were released in two main versions. There is no distinct generational shift between the motherboards; rather, they ran in parallel between 1994 and 1995. Thus, the Narkom 128K v1 became a Krasnodar 128K dektop clone housed in a Corvette case, while the Narkom 128K v2 became a Pentagon 128K compatible microcomputer housed in a Delta case. The name originates from the abbreviation of Народный Компьютeр ("people's computer"). At the company, it is presumed that the decision to launch their own 128K machine was made during the development of the Himac'a 6004 circuit - the appearance of their second-generation machine already closely resembles the Himac 48K. The ZX Spectrum 128K itself was integrated into the 6006, which, according to the manufacturer, offered the best 48/128K compatibility and image quality. The screen could be inverted. The Lprint-III interface and the AY chip were integrated into the 6108 chip. The machine was presented at the Spectrum-compatible computer manufacturers' conference held in Moscow in December 1994. Form company was the main organizer and main sponsor of this event. Representatives from the company present were Borovskij Nikolaj Viktorovic (Боровский Николай Викторович), Eliseev Andrej Jurevic (Елисеев Андрей Юрьевич), Eliseeva Natalja Pavlovna (Елисеева Наталья Павловна), Mihalev Aleksej (Михалев Алексей), Anufriev Vladimir Ivanovic (Ануфриев Владимир Иванович). Pavlovna suggested to the attendees, that since their machine was the most modern, they should accept it as the standard. It is true, that their machines were the most advanced Spectrum clones at that time, but the circuits were highly prone to failure due to their sensitivity to static discharge (15 out of 20 were defective). Thanks to this and the rise of consoles, they weren't successful machines. It is also very likely, that the development of the special circuits consumed significant resources, as we saw with the Profi clones, and thus they ran out money... As mentioned, the first versions were installed into a Corvette case, which bore the inscription Krasnogorsk-128. According to this, they tried to model the Krasnodar, and the use of the optional 580BB55 chip also suggests this. For the RAM expansion, they might have used the VMG scheme. Regarding the connectors, the machine had a keyboard, dual joystick, audio output, and RGB; the audio was routed through the LPT. The motherboard here is larger, and it appeared without a system bus and DIN connectors. The earliest date on the 6006 circuit is 1994/02, so the machine is definitely made after that. The main novelty of the second version is the presence of the system bus. The connectors became integrated, and the motherboard has been designed for the Delta chassis. They removed the 580BB55 chip and replaced it with the Pentagon's Lprint ROM. On the back panel, the reset button is the first. Next to it are the DIN connectors (RGB, CGA, Sinclair, Kempston, power, tape/AY) as well as the printer port. The last one is the magic button. From the front, the floppy connector is on the right, and the system bus is on the left. They provided a one-and-a-half-year warranty on the machines. On the Narcom_2 schematic can be readed 1994/10. The printed date on the Narcom_2 v1.3 motherboard is 1994/12. At the same time, this board features the earliest version of the 6108 chip from May 1994. The Narcom_24 schematics date back to February 1995. In the 1995/7 and 8 issues of Radioljubitel (Радиолюбитель) appared a slim motherboard from the period between the two, already with DIN sockets, but still without an edge connector. [»], [»]
↑date: 2024/12
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1994. 
1994/12. |
| ZX-Atas 128/256 |
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A Zelenograd clone The ZX-Atas clones are not particularly well known. The Atas 48K v1.5 was made in jointly with the identical Kvant-BK MS0530 clone at the Kvant plant in Zelenograd - the latter is much better known by its brand name. These machines usedt he T34VG1 type Russian ULA clones. They came with a built-in Beta-128 controller and power supply. Subsequent versions also have 128/256K RAM and an AY chip with a built-in amplifier and speaker. Allegedly, it had the clearest sound quality, but the volume was uncontrollable and too loud. [»] The v7.9 motherboard is dated May 1994. An earlier version, 7.8, is also known. The machine is IS-DOS compatible. These clones were also known as ZX-Atas or BK-Atas. There are several subversions, as can be deduced from the type descriptions. Based on the Atas 7.9/256/Stereo/PAL designation, machines with 128K, mono and Secam modulators have been also produced. In addition to the usual printer, floppy, edge connectors, which are common on Russian 128K(+) clones, tape I/O, line-level AY-out, external speaker, Kempston/Sinclair connectors were also fitted. The TV picture has RGB and antenna outputs. There is also a magic button next to the reset. [»]
Again a single person revitalizes the clone From Kineshma Pavel Rjabcov (aka Paul) asked on the zx-pk.ru forum for the machine's ROM firmware [»] Soon after, the motherboard he created appeared on the virtual market. On the 20.2x16.8 cm board the edge connector and the HF TV plug removed. The number of memory chips was reduced to 2. [»] ↑date: 2024/12 |
1994/05. 
2017/06. |
| ZX-Next
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Dual Z80 and expansion slots The development of the ZX-Next began in 1989, and the first version was completed by December 1993. Its developers were Konstantin Viktorovich Sviridov, also known as Conan, from Mitiscsi (concept, hardware, documentation), and Leonid Ermakov from Moscow (Video ROM, built-in and utility software, hardware tests, drivers, and other support). Before the development of the machine, they assembled clones developed by others. At that time, Rozhkov Roman was also the member of the team. However, their ventures consistently failed, primarily due to the quality and expandability of the motherboards, the sensitivity of the RU5 memory chips, and compatibility issues. For mainly for these reasons the third member was left. The principles of developing the new clone were reliability, the possibility of smoothness of mass production and software compatibility. Therefore, it differed from the previous clones in several aspects, mainly with its Z80-based video circuit and by the design of the expansion slots. The machines were sold through the company Slot Co. Ltd., which was also based in the capital. According to sources, they initially approached the company for contract manufacturing and later worked there as well. Thus, they first ordered a dozens of motherboards from the company with their own money, which were non-functional without the protected firmware vROM. It only worked for three seconds, during which the operation of the motherboard could be tested. This was to prevent the production of factory pirate copies. Later, the vROM protected against copying from competitors. Approximately 700 units were produced, which were sold either as complete machines or as kits in custom configurations until around 1996. Development ceased at that time, and perhaps the Slot company went bankrupt at this time as well. In any case, they certainly did not function by the turn of the millennium. Besides the two constructorss, the names of Burilin Boris Mikhailovich (Бурилин Бoрис Михайлович) director, Sulgina Irina Viktorovna (Шульгина Ирина Викторовна), and Samylovsknj Sergei Vladimirovich (Самыловскнй Сергей Владимирович) were known from the company. [»], [»], [»] According to the developers of the clone, it combines the advantages of the Spectrum (low power consumption and price) with those of PCs (high resolution screen, easy expandability, standard keyboard, and modem connection possibility via RS-232 port). Mass production was facilitated by the wining of the PCB and the modular design, as well as the absence of special components. Let's start with the Z80-based video circuit. For this, a Z80 (clone) CPU and a 2K ROM are needed, controlled through two free ports. It also performs the critical RU RAM chip refresh and is responsible for anti-piracy protection, as mentioned before. With it, it is possible to implement any timing, whether it is the original ZX, Pentagon, Scorpion, or future developments. With this solution, 17 chips were saved compared to the ATM Pentagon. Not to mention, that this solution was almost completely insensitive to the installed RAM type. The RAM configuration can be different. On the motherboard, the K565RU5 (4164) or K565RU7 (41256) chips can be installed in two rows. In the most basic version, one row of RU5 provides the 48K configuration. Two rows of RU5 gives 128K, and two rows of RU7 makes 512K of memory. A full row of RU7 means 256K, and with half the number of chips, it gives you 128K again. No separate controller card is needed for 48K. Initially, for 128K, the 128K controller expansion was a requirement, but starting from the second version of the motherboard, this is no longer necessary as the function has been integrated. For more than 128K of RAM, the IDE controller card is also required. Finally, for 512K RAM, the Turbo controller is also needed. For 128K, it is possible to copy TR-DOS or iS-DOS to Shadow RAM. With 256K, both can be used simultaneously. The ROMs can be stored in two 27256/27128 chips or in one single 27512 chip. The expansion slots are represent four/five XT-like 8-bit ISA buses. For these, the company offered several expansion cards, most of which were multifunctional. The previously mentioned 128K memory controller includes sockets for AY-8910/12 chips and a ZX Spectrum compatible RS-232 port. The serial port also worked in 48K mode, making the ZXLprint interface unnecessary. The Turbo controller card was included the CPU turbo-, 256/512K RAM controller, a parallel port, the CGA controller, and a real-time clock. Through the IDE controller can be connected the ZX or XT keyboard. Only the Beta-128 controller had a single function. In the comptemporary documentation was also mentioned a 10 Mbit/sec network card, but no traces of it can be found anywhere. According to the author, only four cards were made, which is also stated in the documents. The user documentation also mentions an interface compatible with an HD floppy drive, but again, further details are unknown. However, several VGA cards with 640x400 resulrion were definitely released as prototypes, but only one PCX viewer supported them. This development marked the end of the story, with the previously mentioned date of 1996. Conan and later Ermakov left Slot because they never received larger orders. On these expansion cards they tried to eliminate the known bugs that had become well-known by then. On the Turbo card, the turbo mode can be switched on and off through software and hardware, even while programs are running. When accessing peripherals, the processor speed decreases for improving compatibility. The Beta-128 controller is faster, quieter, more reliable than the original, and functions more reliably with lower-quality disks. The known bug fixes at the time were also applied. On certain motherboard versions, some card was integrated in the empty space on the right side, such as the Beta-128 and the 128K RAM controllers. Almost all motherboards and cards were yellow color, without protective masks, due to cost reasons. However, there was also a green version with a protective layer. Until July 1995, card versions without SECAM encoding were produced, only with RGB output. Otherwise, only the SECAM decoder was a special component in the form of an ASIC chip. Kamil Karimov (Caro, Yekaterinburg) also helped in the development of this. Because the management of Slot was impressed by the image quality of the Secam decoder seen at the Spectrum-compatible computers manufacturers' conference demonstrated with Kvorum machines (December 1994), hence started the collaboration. [»] Regarding the operating system, they relied on iS-DOS, specifically developed at that time for the Spectrum clones, instead of the outdated CP/M system of the Profi and ATM. Slot company was actively participated in the distribution and promotion of the system, as well as in the creation of user documentation. There were three main versions of the motherboard. The 48K basic version was released in December 1993, the 128K version in November 1994, and finally the SECAM decoder version in August 1995. At the same time the IDE controller was released. [»]
The perfect protection The biggest problem with the resurrection was the hacking of the video ROM. Ermakov no longer remembered which 10 bytes needed to be replaced in order to work with any ROM. Fortunately were still available some original motherboards and expansion cards, vROM chips, as well as their dumps. In addition, user documentation and circuit diagrams were left, and P-CAD files were also found. The attempt to hack, which started at the end of January 2005 and lasted for several years, was finally successful by Vitalij Rudenkom (Keeper/Harkiv) and Abramov Mihail (Mdesk/Moscow). Keeper created the virtual video controller in Quartus FGPA project using VHDL language. Mdesk rewrote the firmware with bypass the protection. Firstly, the version without the CGA driver was completed in November 2011, as the single motherboard was enough for that and the Turbo card was not necessary. The initial release was soon followed by some bugfixes. In June 2013, Mdesk created the third version of the motherboard without the SECAM decoder, as well as the circuit diagrams of the Turbo, IDE, and TR-DOS cards in P-CAD 2006. After implementating the Turbo card, the final firmware was completed in December, which also included the CGA driver. This moment can be considered the final birth of the new clone. [»] In July 2017, the ZX-Next 2017 was released by Pavel Rjabcov (Paul/Kineshma). The motherboard, measuring 25x25 cm, supports the mATX standard. It uses the VGA-PAL converter of zst as video output. There is one expansion slot remained, and a single chip of 27512 type can be used as EPROM. The input for the ZX keyboard has been removed, and now besides the XT, the PS/2 standard keyboard can also be used. The stereo sound is output through a 3.5mm jack. Short bugfix instructions can also be found on the forum. [»] Roman Krupnin (RomanRom2, Elite Ltd., Nizhny Novgorod) created the silkscreen printed versions of the motherboard and expansion cards based on the documents published by Mdesk by mid-January 2022. [»] ↑date: 2024/12
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1995. 08. 
2013. 12. 
2017. 07. 
2022. 01. |
| Sprinter
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The FGPA clone from the second half of the 1990s The Sprinter clone series was the brainchild of St Petersburg-based Peters Plus Ltd between 1997 and 2003, very much at the end of the classic ex-Soviet ZX Spectrum era. It was the last 'mass-produced clone', which never achieved breakthrough success. Only 110-115 machines were sold, available as motherboards and ready-made configurations. By this time, of course, thanks to the Internet and the revival of retro fever in Europe, orders were also came from abroad. As an interesting contrast, it was the clone that sold into most, sixteen countries, but also in the smallest quantity. The main designer of the machine was the Kiev-born Ivan Pavlovich Makarchenko (Winglion), a hardvare developer, who died at the age of 47 in April 2013. Peters Plus made several ZX Spectrum clone series from 1989 before the Sprinter, which bore the company's then-name Peters. In fact, even a prototype Sprinter saw the light of day as the Peters 4096. The company was also involved into the production of the disk magazine called Spectrum Progress, which ran for three issues from September 1996 to April 1998. [»] Today we would call it an FGPA emulator rather than a clone, which could be built into a (then) standard Baby AT PC chassis and used PC add-ons. This included the SIMM72 RAM module, power supply, floppy drives, HDDs, CD drives, keyboard and mouse. The two ISA 8-bit slots were compatible with some PC devices, as well as with the PAL encoder and VGA card developed in-house. Using the FGPAs, it can be configured to more computer types, including the little-used own proprietary Sprinter mode with the Estex operating system. The method is called Flex architecture by the company. In addition, of course, it offered ZX Spectrum 128K, Pentagon 128/512K and Scorpion ZS 256 modes. There were three main versions of the machine, with several sub-versions within each. The yellowish-brown motherboard of the 1997 series has a rather "Russian" look. This is no coincidence, as these machines were hand-built. The Sprinter prototype mentioned above was presented at the Enlight'96 party in Moscow in August, according to information in ZX-News#32. [»] The launch was first scheduled for November 1996, then pushed to February of the following year. Even then it was not ready... The 'final' version was unveiled at Enlight the following year, according to Nicron#51. [»] It was then finally released in the autumn. The next, the 2000 version, was distinguished first from the previous series fby the green colour of the motherboard as well as the quality of the workmanship - i.e. it shed its prototype character. Let's see the specs of the Sprinter 97. Its processor is the14MHz in Z80-compatible Z84C15, which clocks at 3.5MHz in ZX Spectrum mode, possible to switching between the two by pressing the F12 key. The FGPAs are the Altera EPF10K10QC208 and EPM7032SLC44 respectively. The RAM size can be from 1 to 4 megabytes, the extra memory of course can be used here as RAMdrive, from e: to t: drive. The extra functions are available from the extended version of TR-DOS. The 8-bit stereo audio is AY or Covox compatible, with quite weak AY emulation. Video RAM is 256K by default and can be expanded to twice that - although no Sprinter program uses more than 256K. The floppy drive is controller is the KR1818VG93, introduced in Beta-128. Other integrated devices include a single-channel IDE and AT keyboard controller, two serial ports and the same number of parallel ports (the latter similar to Centronics). The IDE-HDD uses the FAT-16 specification, so you can use up to 2GB partitions (4 partitions x 2GB, for a total of 8GB on the hard disk). The image can be output to an RGB monitor or TV. In addition to the standard Spectrum resolution, it supports 320x256/256 and 640x256/16 graphics and 80x32 text modes. Tape I/O and a Kempston joystick connectors are also integrated on the 20x16 cm board. The first version of the motherboard was released in autumn 1997. We know almost nothing about it. A photo of the version released the following year was made known to Spectrum enthusiasts via the Internet, and that's what sold the most. A special feature is the halved AT power connector. After another year, a newer revision was born, with only the schematic of the circuitry is known, dated August 1999, and no finished motherboard appeared yet. In the Sprinter 2000, the same processor is now clocked at 21 MHz, also switchable back to 3.5 MHz. The 21MHz is only theoretical speed, because the ULA pulls it back to 16MHz. The video memory here can also be 256/512K, the audio is now 16-bit. The FGPAs are Altera EP1K30QC208 and EPM7064STC100. This allows hardware acceleration of the graphics, implementing buffered Covox and different graphics modes to be used simultaneously. It was also released in three subversions. The Sprinter 2000 and Sprinter 2000 Light were released on a double-sided PCB motherboard optimized for mass production. The standard version was released with 512K vRAM (later only 256K size) and 2 ISA slots, the Light came with halved video memory and no expansion slots. Although there are now two IDE channels, only the first of these can be used. RAM can be between 4 and 64 megabytes. The Light version is rather buggy, for example the FGPA wiring is faulty. The Sprinter 2000s has PS/2 port, and the power connector is full AT length. The original 8 vRAM chips have been halved in number and have become surface mount components. In the case of the last version, that never made into production, the Sprinter 2003s -often called Sprinter 2002s by the community- was removed the PS/2 connector and the SMD vRAM modules were mounted in a checkerboard pattern. No other differences are known (yet). Its documents found dating December 2002, hence the 2002s/2003s dual designation.
Revival based on published documents Peters Plus stopped producing the clone in 2004. After that Mak published the information on the zx-pk.ru forum in 2007, with the exception of the FGPA firmware. [»] and [»] The source code for this was tried to acquire by NedoPC for a small-scale re-launch, but Peters asked $10,000 for it... By the end of 2009, the firmware was also became freely available. [»] After that, the Sprinter 2000s replica motherboard by fifan, who is living in Lyantor, became operational. [»] The designer launched another series in July 2013, this time without the floppy controller chip and with more advanced power supply circuitry - although the latter may have been used in the earlier version. [»] According to freely available documents, firstly loxic from Novosibirsk decided to build the Sprinter 2003s mod.2009 loxic replica [»] The Dnipropetrovsk-based Alexander Korovnikov (aka Zorel) started work on the Sprinter 2003s mod.2012 Zorel in July 2012. [»] The bugfixed motherboard was available for order by October of the same year. [»] The Sprinter 2016s motherboard was originally made by Mikhail Tarasov (Mick or Micklab) in Kaluga, Russia, in November 2016. This is not a simple 2003s replica either, but a slightly alternative reimagining of the original. The most important change is the installation of an ATX power connector, unfortunately this is really only provides power, the more advanced controlling logic has no remain place on the board. Some circuitry has also been replaced for better operation. The most important of these including the modifications of the components responsible for controlling the AY-chip and the VG93. [»]
The Sprinter 97 replica was never fitted with any parts, so there are no test results of its operation. Mick finished the board in December 2016. [»]
The legend returns The Sprinter Team started its 'third coming' in November 2020. The coordinator of the group, which was formed by the members of the zx-pk.ru forum, is Roman Krupnin (RomanRom2, Elite Ltd., Nizhny Novgorod). Archiving the documents, communication between members, coordinating new developments... these are the main tasks, of course, mainly in the on-line space. The first product was the announcement of the Sprinter 2020i motherboard, currently under development, by Krupnin on the above date. It is ITX standard and will be implemented on 4 layer PCBs. All parts are SMD components except for the ROM, which at this stage of development is a through-hole design. The Sprinter 2016s-fix1 from Dmitry Aleksandrovich Mihalchenkov (aka Hard) is from Dzerzhinsk, end of July 2021. [»] The former Witchcraft Creative Group programmer has moved the JTAG connector to a more convenient location, more away from the floppy’s. In addition, he changed the location of the capacitors responsible for powering, so that the newer, larger diameter pieces would fit without a problem. The main new feature of the Sprinter 2021s (aka Sprinter 2016s-fix2) is to fit into an AT-standard case, instead of the now scarce Baby AT. The 1.7 cm wider motherboard could accommodate a third ISA slot. Elite Ltd. has integrated improvements and bugfixes from Zorel’s Sprinter clone. The electric power supply has also been improved, and the joystick connector has been redesigned. The tape I/O connectors have been removed and replaced on the HD Audio. There is a jumper to choose between the two ROM sets. The component labelling has also been standardised. The Sprinter 2022d is an 'improved' version of this, using DIP encapsulated video RAM, because they are cheaper. The development was completed in November 2021, and by New Year's Eve a working, assembled motherboard was released, also from RomanRom2. [»]
↑date: 2024/12 |
 Sprinter prototype1996.  Sprinter 97 v19981998.  Sprinter 20002000.  Sprinter 2000s2003.  Sprinter 2003s2009/10.  Sprinter 2016s mod.2017 paul2017/10.  Sprinter 97 mod.2016 mick2016.  Sprinter 2016s-fix12021.  Sprinter 2021s aka 2016-fix22021.  Sprinter 2022d2021/11. |
| ZX Spectrum 128K+3e on Altera DE2-115
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From Novosibirsk anton95 was joined to the Spectrum community with a ZX Spectrum 48K clone and then with a Profi. He rethinked Mike Stirling's project, which was ready for December 2012. It used the Altera DE2-115 card, so it became possible to emulate the ZX Spectrum 128K+3e. The aim of the project was to recall the youth in addition to practicing the VHDL language. [»] The Altera DE2-115 development board is built around the Altera Cyclone IV EP4CE115 FGPA. It has 114,480 logic gates and 475K of built-in RAM. The board is equipped with 128MB SDRAM, 2MB SRAM, 8MB FlashROM and 4K EEPROM. It has 18 two-position and 4 microswitches. 18 red and half as many green LEDs and 8 7-segment LEDs are used as indicators in addition to the 2x16 matrix LCD. The sound here is already 24-bit, with line in-out and mic-in jacks. As for the other connectors, double Gigabit Ethernet, SD, one USB 2.0 A and two B (device, host, blaster port) VGA, RS-232 , PS/2, TV-in decoder can be found. The firmware clone uses Goran Devic's A-Z80 core. YM2149 FGPA code from MikeJ has been debugged. The emulator provides 512K RAM for ZXMMC with SD card support. The processor speed can be 1x, 2x, 3x and 4x. ↑date: 2024/12
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 ZX Spectrum 128K+3e on Altera DE2-1152012/12. |
| RU-12. AVR ZX Spectrum |
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The AVR ZX Spectrum clones are connected to the name of Vasilij Lisicyn from Ryazan - although the forum members of zx.pk.ru also took an active role in the development. The 'series', consisting of two major versions, was named after its main components, the 8-bit RISC AVR microcontrollers from Atmel/Microchip Technology. These are the ATMega 128-16AU and the ATTiny2313(A)-20SU, which are based on the modified Harvard architecture. The clone was released originally under the name ASPECT 128 AVR ZX Spectrum, and later received a nomenclature with version numbers. Development starting in mid-June 2012 [»] for the AVR ZX Spectrum v1.0 in which the processor is emulated by the ATMega microcontroller. The same type is responsible for simulating the video circuit too. The PS/2 keyboard is controlled by the ATTiny one. By the end of June 2013, Ramiros' AY emulator was also integrated into it. At the same time, the display became full color and the system also received a PAL encoder. Since the Z80 emulation was already bug-free (apart from the effective speed of 2.333MHz), this can be considered the final release date of the clone, since the hardware-firmware combination performs the emulation. [ »] This firmware clone is compatible with ZX Spectrum 48K/128K/128K+2/+3 and Pentagon 128K machines up to three 16K ROM sets. In principle, it can emulate Spectrum models up to 512K RAM. Undocumented instructions of the Z80 processor are also supported, as is the shadow screen for the 128K models. The programs are loaded from the FlashROM of the microcontroller emulating the CPU. That is why it can be considered a prototype, since we are not talking about a machine with a mass-storage that can be used by anyone. (Additionally, a firmware package emulating a Russian clone named Orion 128 was also released at the end of October.) In November 2013, he started to prepare the microSD card support, which is based on his self-developed SD-DOS. [ »]. This also made it possible to clone the GDR Robotron1715 machine. The SD card part of the Spectrum part was ready in mid-March 2014, which is based on the FAT32 system. [ »] This actually means the starting the development of the second version, AVR ZX Spectrum v2.0 at the end of June 2014. [»] Among the constructor's goals was, that the AVR clone could also be installed in a PC keyboard. At the same time, in March 2015, v1.1 was also released with SD card support and microUSB power supply. [ »] Here the SD unit must be inserted into the JTAG connector. It was also smaller than the v1.0/2.0 variant, so there is a good chance that it was the smallest clone of its time. It carried the functionality of v2.0 in a different form. Going back to v2.0. Of course, it also has microUSB power supply, but the sound system and the Kempston joystick emulation are implemented with a separate tinyAVR connected via an expansion port. Thus, this version could already support much more, 82 dedicated PC buttons. The range of usable firmwares has been expanded with the ZX Spectrum 48K 2006 and the 48K and 128K versions of OPEN SE BASIC. Video output realized by a row of pins as RGB or as black and white (more precisely, 8 shades of gray) screens. A dedicated, compact PAL encoder is also available. The audio out and the I/O connector of the cassette unit are both stereo 3.5 jacks. Initially only .Z80 files were supported by SD-DOS v1.0, [»] then the .SNA support was born. [»] Finally, .TRD's with SD-DOS version 2.0. This can be considered the full completion of this version with the May 2015 date. [»] The v2.1, released at the end of 2015, uses a four-layer PCB, thus stability was improved. Effective speed of emulated z80 CPU was increased to 3.5MHz from this version. [»] Then Turbo Sound support appeared [»], later supplemented with Kempston joytick. [»] This became v2.2, which was released in mid-April 2016. The TS got a separate jack, the joystick port became a PS/2 standard. He has published documentation for both v1.0 and v2.0 on radio-hobby.org and meandr.org websites, among others. In addition, the author appeared on Russian and international forums with the presentation of v2.0. However, the documentation for v2.1 and v2.2 is only available via the zx.pk.ru forum(?). Discussing here briefly about the common components of the two clones. The main parameters of megaAVR are the 16MHz clock frequenzy, 4K SRAM and the same amount of EEPROM,and 128K FlashROM. Ticking at 20MHz, the tinyAVR contains 2/4K Flash, 128/256 byte EEPROM and SRAM. The 'A' versions here are more energy efficient, but cannot be overclocked. From Kineshma, the already mentioned Pavel Ryabcov (commonly known as Paul) released his own version. Unfortunately, the August 2017 machine turned out to be quite buggy, partly due to the two-layer implementation. [»] ↑date: 2023/07 |
| ZX Spectrum 48K on STM32F407VGT6 and LGDP4532
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Egor Belousov (Егор Белоусов) aka Gorien presented his first ARM-based project, a firmware ZX Spectrum emulator in October 2013. [»] The ZX Spectrum 48K on STM32F407VGT6 and LGDP4532 is based on the namesake microcontroller and LCD. The author made the source code of the clone open access, so the developers of the easyelectronics.ru community could actively contribute their bugfixes and improvements. The author used the STM32F4 Discovery development board (or STM32F407-DISC1 as its new name). The microcontroller on it uses the ARM Cortex M4 processor, in this case we are talking about the 168MHz version. The size of the RAM is 192K, with a 1024K FlashROM. From the point of view of emulation, the existence of the integrated amplifier is also important. Of course, the USB connector can also be found on the page in the form of a Micro AB variant. The Mini USB port is for the JTAG programmer. The LCD is a screen with a resolution of 320x240; it has 8, 9, 16 and 18-bit parallel and serial connection modes. It can display 264144 colors. Due to the color depth and resolution, the graphics RAM size is around 170K. The card and the screen are connected 16-bit parallelly, supported by DMA, enabling 50FPS display. A 40-key Speccy-compatible keyboard and cassette unit (or tape recorder emulator) are connected to the system. Later, the author also created SD card support. Thanks to open source and community development, LCDs based on the SSD1289 driver chip and PS/2 keyboards are became supported. Also the result of the community development is the increased stability of the firmware clone, the precision of the timings and the possibility of using .SNA files. ↑date: 2024/12
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2013. 10. |
| ZX Spectrum 128K on Marsohod2
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The Inpro Pljus company from Taganrog is the contractor of electronic projects for third party clients. Project analysis, printed circuit production, component selection and installation, firmware programming, creating drives for the developed devices... these are mainly included in their profile. The Marshod series includes their own development cards. Marshod2 is the second member of the series, for implementating of projects of medium complexity - therefore ideal for realizing a ZX Spectrum clone. The type of FGPA is Cyclone III EP3C10E144C with 10K gates and 53K RAM. For this, is connected 8 megabytes of SDRAM. It has a two-channel USB 2.0 interface, one of which also serves as JTAG programmer. There are also two freely definable microswitches and four indicator LEDs on the board. The system bus has 16 user-definable pin connectors. The image is received via a standard VGA output. The 5 volt power source can be connected by a 2.0 USB-B cable. The Ethernet, PS/2 and USB modules, as well as the seven-segment display module, which were also developed by the company, can be connected separately.
Chaosorg, also from Kislovodsk, proposed the idea of further development of this project in March 2015. Before all of this, he made a bugfix related to the #FE port, which the project inherited from Ewgeny7's article. Thus, the color of the border can now be changed. The goal was to support the tape I/O, beeper, and to rewriting the memory manager. According to his intentions, the system should also support loading in turbo mode. Furthermore, it was necessary to make a video controller module in order to work with modern LCD TVs. [»]
For him was joined in May Vise from Yekaterinburg, who added a tape in routine to the FGPA code. [»]
In the same month, Vise found an AY routine on OpenCores.org. He ported this SQMusic module into the project and laced it into the firmware as it was made in Aeon Lite. [ »] In the case of the 128K Spectrum module, due to the size of the ROM set, the video memory had to be placed out into the SRAM. At the same time, he replaced the original softcore T80 CPU with the bug-fixed one of the AeonLite. [»]
↑date: 2025/01
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2015/11. |
| RU-15. Sizif series |
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Evgenij Lozovoj [↓] (i.e. Eugene L or UzixLS) from Belgorod, Russia, started creating the Sizif-128 machine back in 2019. The goal of this was to create a minimalist Pentagon 128K 2+ ATM compatible clone. Since then, the initiative has expanded into a series, supported by the members of the zx.pk.ru forum. On the engineer's own Github, the information needed to construct these machines are available. [»] You can also order ready-made motherboards from the Chinese PCBWay site. [»] So let's see the machines! 15.1. Sizif-128 The processor of the first series, the Sizif-128, is a Z80 ticking at 3.5MHz accompanied by 128K RAM. The sound chip is also the original AY/YM with mono sound. The peripherals of the clone are emulated by the Altera EPM7128SLC84 CPLD, including the PAL encoder optimized for CRT devices. By February 2020, the first version on the prototype card was ready. The 85.1x140cm, April rev.A was bugfixed in October for the suggestion from the capital from Andrei Firsanov (Andrey F). Thanks to this, compatibility with LCD TVs has been improved, as well as the RGBI color balance. [»] The rev. B was expanded with power LED and reset buttons, but the NMI switch was removed and the input of the cassette unit was replaced with the 74HCU04 inverter by the constructor. The PAL color signal could be adjusted with a potentiometer. This revision was not published as the input of the cassette unit became buggy. Therefore, for the July 2022 rev.C, this input is reverted back to the transistor solution of the revision A. The PCB wiring has more nice design, and the video circuitry is calibrated for the best color fidelity. The C1, drawn in the same month, had improved tape input sensitivity for the suggestion of the Moscovian SerOne. [»] The ideaman also created an improved wiring diagram. It contains RBG video and stereo audio output. [»] 15.2. Sizif-512 The Sizif-512 6.5x21.3cm dual-layer motherboard can be placed into ZX Spectrum 16/48K or replica chassis. The circuit, with roughly half the size of the original Spectrums, also received an internal expansion bus. This allows to connect an expansion card to the motherboard, also constructed by Lozovoj. It is compatible with ZX Spectrum 48/128K, +3e and Pentagon timings. The Z80 processor operates in 3.5, 4.4, 5.2, 7 MHz no-wait, and 14MHz wait state turbo modes. The RAM size here is now 512K and the AY-chip can play ABC/ACB stereo alongside the mono mode. Peripheral emulation is carried out by the Altera EPM1270 CPLD. It also supports PS/2 tastature, Kempston/Sinclair-standard joysticks, and a 6-button Sega controller. The microSD card can be used in DivMMC and Z-Controller compatible modes. TV PAL and Sega mini-din9 RGB video output can be found on the board, as well as a pin header line for PC-EGA monitors. In addition to the standart Spectrum screen, it also supports the ULAplus standard. The mono Covox is Pentagon standard and SounDrive is also emulated. The cassette unit can be connected via a 3.5 jack or the optional Bluetooth module that fits through a pin header. It has reset and magic and, of course, power button pins. The input of the power source can be ranging from 9 to 12 volts without polarity sensitiveness. The RAM can be configured in two ways. By inserting a microSD card, 128K in DivMMC mode can be used via the 7FFD port (Pentagon mode), 128K can be used via the DFFD port (Profi mode, the most compatible with old 128K software) and 128K is reserved for DivMMC. If DivMMC is not activated, then 128K is available in Pentagon mode and 384K in Profi mode. The rev.A here it was also the first edition to be released in late April 2020. Revision B didn't come out here either, only the files were archived. On the rev.C motherboard, the Beta-128 interface was removed and the mono sound appeared. Of course, bugfixes are also were made on the board published in May. The July C1 board can be considered as a practically error-free base. Rev.D, with the full specifications mentioned above was released in September, followed by the D1 motherboard in February 2021 with minor changes to the PCB. The September 2022 rev. E also contains some bugfixes. Rev.E1, which was released at the same time as the previous one, is the version without the experimental functions. The first version of the extender card designed for the motherboard, the Sizif-512 extension rev.A was released in May 2021 and then took its final form the following month as rev.A1. This expands the sound capabilities of the motherboard. Offers Turbo Sound FM, 512K General Sound, SAA1099, and Midi sounds. With it, the rubber key (replica) housing is already fully filled. The Sizif-512 Wifi ESP 8266 based Wi-fi module, like the Bluetooth one, is also connected to the motherboard through a dedicated array of pins via the AY-chip. Revision A was published in late April 2020, revision 'B' in July, and revision 'C' in the last days of February of the following year. 15.3. Sizif-XXS The specifications of Sizif-XXS roughly correspond to the versions 512. It is produced in two sizes. The main version is 10x2.45cm and the Zero is 6.5x3cm. The differences from the Sizif-512 are, that it does not handle the 14MHz mode, and the audio part is already integrated into the Altera EP1C3T100 FGPA. Furthermore, it only contains PAL composite video output, Kempston is emulated on the keyboard. There is also SpecDrum emulation. Although it is possible, that with a firmware update, this device can also be used in the 512. Power source is a 5 volt microUSB. The impressive size was achieved by the constructor with the four-layer PCB and the double-sided SMD part soldering. The first, rev.A at the end of November 2020, the bugfixed rev.B was released in February of the year 2022. The Zero, based on it was out on the first day of July. ↑date: 2022/10 |
| RU-16. ZX Coffee Classic |
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In August 2020, Coffe Coffe from Odintsovo presented a portable ZX Spectrum clone. [»] The ZX Coffee Classic is a 10x9cm 48/128K compatible machine. This is the second clone of the constructor. The first was already born in the classical era, made in Moscow in 1986. Its unique characteristic is that, compared to contemporary clones, it solved the 64K RAM with 8 chips instead of 16. A common feature in his old and the new clone is that both can copy the contents of the ROM to the RAM at boot time. Not only because it is 'Classic', but because it also works with PAL televisions and contains real Z80 (Z84C0010) and AY-chip (AY-3-8912A). Let's see the machine itself, about which the author made a very detailed YouTube introduction. [»] Under the LCD screen is the 10MHz Z80 CMOS processor, which can operate in 3.5 or 7MHz no wait turbo mode. Next to this is the Altera MAX II EPM570T100C3 CPLD. The size of the SRAM is 128/256K, the FlashROM's is 32MB. The designer chose this because of the unreliability of SD cards. The chip can withstand 100,000 rewriting cycles, with 20 years of data retention. We can compile and update the ROM set with a Windows utility, it can also be used as a database. The Microchip PIC18F25K22 microcontroller responsible for controlling the peripherals is located in the same place. For example, it copies the Spectrum ROM from Flash ROM to RAM. A 16-bit, ILI9341 controller, 2.8-inch 320x240 resolution LCD unit can be used as a screen. The part outside the 256x192 resolution is the location of the OSD. External units can also be used via the already mentioned PAL composite RCA connector, as well as the S-Video output, which ensures better image quality. The built-in and external screen can work in parallel. Next to the TFT LCD, the AY chip is located with a stereo 3.5 jack. This can also be used to connect the cassette unit. An RCA mono out has also been placed for the sound in the upper part. In addition to the integrated mini unit, the keyboard can be ZX Spectrum matrix or PS/2 standard. In this case, the firmware can also be controlled with the function keys. F1/F3 resets or pauses the Z80 processor. The status bar can be turned on/off with F2. The F4 key calls the game menu. F5 and F6 toggle between normal and turbo modes of .TAP/CPU. By pressing F7, can be started the asynchronous serial (UART) connection with the PC. F9/F10 starts/pauses the .TAP files. Pressing F8 gives help, F12 is to exit. The ZX matrix and the debugger circuit can be connected via the row of pins below the LCD. The built-in keyboard can even be cutted off, in which case the height will be 7 cm. The LCD screen can also be removed. The power supply is possible via a microUSB port, so it can also be operated from a power bank. It also ensures connection to PCs. There is also a reset button. The GameNavigator firmware currently supports .SNA and .TAP files. In the latter case, a counter shows the loading progress. In addition to tape files, it is also possible to save at normal or turbo speed. Based on the database created on the PC, the year of publication and the publisher can be seen in addition to the title. In addition to the tape file status indicator, the ZX48/128K mode, normal/turbo CPU speed, and AY-chip status indicators can also be seen on the border. The consumption became below 170mA, half of which is accounted for by the PS/2 keyboard, the LCD backlight and the AY-chip. The turbo mode of the Z80 only increases the consumption by only 4mA thanks to the modern CMOS technology. The relatively big 3.3 volt undervolting instead of the default 5 volts plays a role in the low consumption. Except for the AD725 type PAL encoder and the AY-chip, everything runs on 3.3 volts. ↑date: 2022/11 |
| RU-17. ZX Spectrum 128K+++ |
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Aleksandr Svincov, aka AlexB5 has come out with his ZX Spectrum 128K+++ clone from Novosibirsk. The machine, which was released in January 2021, really has some ‘plus’es compared to the original 128K machine. The Z80A processor and the 128K RAM are of course the same, but new connectors have been added. The power supply is IDE/ATX standart, and the picture can be obtained either via VGA or RCA composite connectors. Among the traditional Spectrum connectors, the two pieces of 3.5 mm jacks are for the cassette unit and the sound output, the DB9 is for the joystick. It is possible to change the timings to Pentagon 128K and connect Beta-128 or an emulator to the machine, in which case you have a full Russian clone. Including the stereo YM2419F chip and the 7MHz overclock even in no-wait, i.e. real 2X speed mode. Latter ones can be set using jumpers. All documentation, including bug fixes and the P128K modding, is freely available. ↑date: 2021/10 |
| UA-1. Speccy 2007/2010 |
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1.1. Speccy 2007 and its moddings The Speccy 2007 is a creation of Kiev's Peter Kitsun, aka syd, from December 2007. Both the firmware and the wiring diagram are free to access. The main components of the 13.3x11 cm motherboard are the Z80 CPU, the Altera 7128 CPLD, ATMega16 microcontroller, two pieces of RAM and their corresponding buffer chips, as well as ROM. The author used the ZXGATE clone's code. The machine has PS/2 keyboard, RGB-out, audio output, SD/MMC card connectors in addition to the power source. From the mass storage we can load.TAP, . TZX and .SNA files with double speed. Kempston and Sinclair joysticks are simulated by the keyboard. It also works great with the Z80 socketed AY adapter originally developed for the Pentagons. The date of the first documentation of the bugfixed version 1.03 is January 2008. [»] At the end of February 2008, TR-DOS-supported firmware modding from Moscow from Denisv was released. This requires a replacement for the ATMega 32 controller, which has twice the capacity and has a fully compatible leg layout with the Type 16. The v1.04 machine is the . TRD, . SCL and . FDI files are supported. [»] Fifan, who lives in Lyantor, decided to make his own version in March 2008, which was ready by the middle of the month. Here, the constructor used the type 27512 EEPROM instead of FlashROM. The picture and sound were outputted on a Scart connector on the 17x9 cm sheet. The orientation of the elements has also changed. [»] Of course, the implementation of 128K modding wasn't take long in coming either. It was in the New Year when aniSKY decided to make the 128K version. This was accomplished with the help of one piece UT621024PCL-70LL RAM chip. [»] Members of the zx.pk.ru virtual community were joined to the development, highlighting among them Aleksandr Molodtsov (aka Molodtsov Alex, Kolpino). In April 2009, the finalized wiring diagram of Speccy 2007 v1.06 was released, which was already operating in the 128K+AY+TR-DOS mode. It is an additional board with the applied motherboard and firmware modding. The daughterboard must be inserted into the socket of one of the RAM chips. This version already can handle SDHC cards larger than 2 gigabytes. A Pentagon-timed firmware modding was also made for it. [»] Vyacheslav Georgievich Skutin (Alex_NEMO, aka Captain Nemo) of Kamyshin was published a complete wiring diagram a few days later. [»] For this, molodcov_alex also made the Pentagon compatible modding on the same day. This brings us to the 'single-board' versions, where these moddings are integrated into a single motherboard. For the call of Sabirzhanov Vadim Mirzhanovich (zst) from Chelyabinsk for the implementing the 128K+TR-DOS+AY combo, two applicants were appared. [»] By the end of March 2010, elker was ready with his motherboard. The constructor's card from Orsk integrated Zst's VGA & PAL card, the sound was also outputted through two RCAs. [»] From St. Petersburg, Ljubitel appeared in May with his development. [»] Zst used the version of elker. Later, Alexander Korovnikov (Zorel, Dnipropetrovsk) also made a series from it [»] After several years of absence, by April 2016, Eugene Akhramovich (aka .jackson) from Minsk had created his own version, which uses a single RAM chip. [»] He was also archived the project on GitHub. [»] Pavel Rjabcov's version (aka Paul; Kineshma) is based on this from the end of August 2017. The white and green boards are technically the same, but the latter was achieved to fit into the 10x10cm size thanks to optimization. In addition to the AY chip, the Atmega8 microcontroller that emulates it, can also be used in the mainboard. The socket of the AY chip disappeared from the black version, leaving only the Atmega8's. [»] It was received a bugfix in August 2019 for the suggestion of forum member Rem22 from Penza. [»] In September of 2020, completed the development of his own version of 74ls00 based on Ljubitel's variant. The board's novelty -whis was remained in test phase- are the PAL encoder and Scart connectors. [»] 1.2. Speccy 2010: with new firmwares The successor to the previous clone, the Speccy 2010, is a motherboard created using the Altera Cyclone II FPGA (EP2C8Q208C8N) and the STMicroelectronics ARM7 (STR750FV2T6 or STR750FV2T6) microcontroller. The memory can be 16 MB K4S281632J-UC75 or double the sized K4S561632J-UC75A SDRAM. It was inherited the dimensions of Speccy 2007 and the main features of v1.06. [»] Virtually, you can create a wide variety of configurations, the ZX Spectrum 48/128K, Pentagon 128/1024K, and Scorpion ZS 256K modes can be choosen as standart. It has an SD/MMC card slot. The real-time clock type is Dallas DS1338Z-33+, in this case it emulates Gluk RTC.In terms of ports, it has 2 pieces of PS/2 (keyboard and mouse) and 2 joy connectors, as well as an optional USB (virtual COM port). The mouse is Kempston compatible, joystick type can be of several standards. For video outputs, you can choose to see the image on RGB, Composite, S-Video or VGA, which is produced by 3 R-2R DA converters. Audio production is the responsibility of the double R-2R and TDA1543. (Stereo) AY/YM modes, TurboSound and of course the Beeper are supported. Emulating the C64's SID chip stuck in an experimental phase, as was the implementation of the 16C graphics mode. In addition to being perfectly compatible with Speccy2007 v1.06, it also received many new features. An example is the 1 megabyte usable memory (the aforementioned Pentagon 1024K emulation). The turbo speed can also be adjusted in several stages for the virtual Z80 processor: 7, 14 or 28 MHz. The FPGA can be updated through the card reader, the microcontroller via the virtual Com port. After syd got out of support for the project in November of 2012 [»], the machine received a new firmware on two branches. One of them is the port of TS-Conf from the ReVerSE-U16 clone. This was done by the Ukrainian MVV, the creator of the clone in October 2014. [»] The other system is the work of Martin Borik (mborik) from July 2018. The programmer from Košice added support for DivIDE/DivMMC and MB-02+ units, as well as a file manager and debugger to the original code. He was got a lot of help in the work by the Czech/Slovak Spectrumists. [»] ↑date: 2022/09 |
| UA-2. ReVerSE Ux |
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The ReVerSE Ux is the FGPA clone series of mvv (aka vlad) from Cherkasy, Ukraine. The zx.pk.ru community also actively contributed to the hardware development and the creation of the firmwares. Thanks to this, extensive emulation of 8-bit international and ex-Soviet computers and consoles became possible. The ReVerSE-U10 was the first member of the series, presented in December 2008 by the designer [»]. In fact, it can be considered a prototype, as apart from the developers of zx.pk.ru, other owners are not very known. The type designation of the motherboard is U10EP3C.
For the October 2010 released ReVerSE-U9 (ie U9EP3C), the FGPA type is the same [»]. The SRAM has a fixed size of 512K, but received 32 Mbyte SDRAM as standard. This can be 8 or 16 with smaller modules - more than enough for emulating 8-bit microcomputers. A TDA1543 amplifier can also be found on the board. Compared to its predecessor, the audio codec IC, the audio input, and the double USB port have also disappeared. The latter were replaced by a miniUSB one, which also serves as a JTAG interface in addition to the traditional JTAG connector. As a system bus, there is a 3- or 5-pin connector on the 7,5x7,5 cm PCB. In the case of ReVerSE-U8 (U8EP3C) clone from August 2011 can be doubled the basic 512K SRAM. The codec chip and the audio input were appeared again. The system connector consists of an 8, a 20 and a 26-pin row. The size of the board has not changed compared to the predecessor model. For the ReVerSE-U16 released in April of 2014 [»], the central unit is the Cyclone IV EP4CE22E22C8N, but of course it is also compatible with the EP4CE6/10/15 types with a lower logic gate number. RAM sizes for these FGPA chips ranging from 34-74K. In addition, it also works with the Cyclone III generation, surely with the EP3C5/10/16/25 types, which have 53-76K of internal memory.
For U9, U8 and U16, mvv unified the Speccy config. The virtual processor is the T80, which can runs at 3.5, 7, and 14 MHz. As for the sound, the beeper, a 21 MHz 448K General Sound sound card with ROM 1.05a, a Turbo Sound using two AY-3 8910s, SounDrive version 1.05 and Covox from the #FB port are present. It handles RAM up to 4 megabytes via #DFFD (Profi standard) and the Pentagon #7FFD ports. In this case too, the real-time clock works according to Mr. Gluk's scheme. The Kempston mouse is also emulated here, the Kempston joystick is also available via the numeric pad. The mass storage devices are Z-Controller and DivMMC. The upscaler works at a resolution of 800x600 in the case of the ZX at 50Hz, and in the Pentagon mode at 48.
↑date: 2023/01 |
| UA-3. DivGMX |
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DivGMX is the development of the aforementioned mvv, which was launched in November 2016. It is a dual function FGPA based card. On the one hand, as an interface, it opens the expansion possibilities of the Spectrum and compatible machines. On the other, as a standalone motherboard, it can also function as a clone. Originally, the 'basic' version would have been the extension interface, and the 'ultimate' the 2-in-1 extension card and clone. In the end, only the latter was realized after five years of development, which, of course, was also facilitated here together with the members of the zx.pk.ru community. [»] The type of central unit, the FGPA, can be Cyclone III EP3C5/EP3C10 or Cyclone IV EP4CE6/EP4CE10. The logic gates and RAM in the first case are 5/10 thousand and 53K. For the second, the number of gates are 6/10 thousand, the memory size is already 270/414K. The card also has 4/8/16/32 megabytes of SDRAM. Flash can be 8/16/32/64 Mb. The real-time clock type is DS1338Z. Of course, the JTAG connector and the i2C bus are also present for programming the FGPA. NMI and reset buttons, stereo 3.5 jack can also be found on the 7.4x5.4 cm board. In addition to the Sinclair edge connector, it is of course also compatible with the Russian Nemo bus. By default, it can be connected to the latter, and with a female-to-female adapter for Sinclair machines. It has USB keyboard, mouse and gamepad connectors and an HDMI TV output. Among the controllers, it was tested with Defender Game Master G2. A MicroSD card serves as mass storage. Regarding of the emulated machines, all the classics Spectrums are supported from 16K to 128K+3. Of course, it can also simulate Pentagons, with 128, 256, 512 and 1024K RAM. Among Spectrum hardware, CMOS (Mr. Gluk standard), DivMMC, DMA Ultra Sound Card, Data Gear, General Sound 512K, Kempston joystick, Kempston mouse, Multiface, ZX Interface 2, Sound Drive 1.05, Turbo Sound (2xYM2149), Turbo Sound Easy (2xYM2149 + SAA1099) and Z-Controller are supported. With the basic firmware, connected to the Spectrum, we get the picture in 640x480 resolution at 60Hz via HDMI. The sound can be SounDrive or Turbo Sound Easy. The mass storage device is DivMMC and Z-Controller. With the virtual processor, in addition to the 3.5, 7 or 14 MHz turbo also can used. In terms of Spectrum compatibles, it can emulate the Alf game console, the ZX Evolution with TS-Config, and the 256-color virtual Spec256. Unfortunately, despite being open source, no one supported it, so the author also abandoned the projekt. The card by Piotr Bugaj from Czestochowa (Zaxon/Speccy.pl) and Pavel Ryabcov from Kineshma (Paul ) is (was) available to order. ↑date: 2023/01 |
| UA-4. Karabas series |
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4.1. About the constructor in brief Andy Karpov (andykarpov), a web developer and radio amateur from the Ukrainian city of Nikopol, regularly delivers several smaller and bigger developments to the Spectrum community. Due to his interest, besides retro console and computer (mainly Spectrum) developments, he also has things related to amateur radio in his repos. [»] 4.2. Karabas-128: his first ZX clone The aim of the Karabas-128 clone was to create a ZX Spectrum 128K motherboard with a real Z80 processor and the Altera EPM7128STC100 CPLD, which can be produced cheaply and installed into a 16/48K chassis. The firmware for the ULA emulation is based on the Speccy 2007 clone. Thanks to the single RAM IC modding from .jackson, only requires one RAM chip to be built. The AC/DC circuit, cassette unit and PAL coder are derived from the Harlequin 48K rev.G clone. In addition to TV-out, an RGB monitor port also included for motherboard, and the AY-chip was integrated too. The original edge connector can also be found. The timing can be ZX48K or P128K compatible. The first revision, rev.A, was released in June of 2017. This was followed by regular bugfixes and updates such as rev.B and rev.B1. The Rev.A2 board was created by Nikolaj Kalaburdin, i.e. NiKa from Yekaterinburg, but his first PCB is only labeled as Rev.A. From Kharkiv Oleg Starichenko (better known as: solegstar) in August added a 1024K expansion, which is compatible with the Profi clones. [»] 4.3. Karabas Nano: the smallest clone The idea of the Karabas Nano clone was to create the smallest and cheapest compatible ZX Spectrum clone with keyboard using a real Z80 processor and an Altera EPM3256ATC144 (later an EPM7512) CPLD. Andy also wanted to mastering the use of the KiCAD program. The size of the clone series, which were made with surface-mounted technology is 10x10 cm. Development began in July 2019 with prototype rev.A and rev.B boards. The circuit diagram is based on the Karabas-128 clone. The operating scheme of Wi-Fi and UART comes from the ZX Uno project. Apart from the CPU and CPLD, the main components are the 2 megabytes of RAM, ROM, PAL encoder and the Amega8 chip emulating the AY chip, last one is soldered on the back. The edge connector is also present, located between tape I/O and the power connector. This one is not the standard type, it has pin-header. The video out here can also be RGB or PAL, with the latter integrating the AY chip audio. The motherboard includes a microSD card reader and supports some different configurations. First one is based on the Z-Controller. It has Pentagon timings, 1024K Profi memory management and the Gluk reset service monitor. Another factory configuration is with the DivMMC interface, 128K Pentagon timed clone with ESXDOS operating system. Of course, this has also undergone several revision changes. Rev.C has a removable keyboard and is only compatible with AEG format processors. In the case of Rev.D, the keyboard is now integrated and supports lower-cost FEC socketed CPUs. Inline with this version, was developed the ESP8266 based wifi addon card. The Timex Hi-res graphics mode is implemented as well as ZX-Uno compatible UART mode. Rev.E already has integrated Wi-Fi module, which is placed on the other side of the microSD slot. At Rev.F, the Wi-Fi module and microSD socket changed their places. The buttons have become smaller on the now rounded edged motherboard. In the case of Rev.G, the microSD slot became a reversed orientation type. As it is placed at the bottom of the board, this is natural for use. From the city of Belgorod, Evgeny Lozovoi (UzixLS, Eugene L) made some changes to the mainboard starting with Rev.I and also produced the Turbo Sound compatible firmware. In the case of rev.J, the jacks can no longer be only surface-mounted and the AV-out can be selected with a jumper. [»] 4.4. Karabas Pro: the Profi compatible Karabas For information about the development launched a year later, see Profi v5.x compatible Karabas Pro FGPA-based clone in chapter 3.2. [›] ↑date: 2022/10 |
| UA-5. Buryak PI |
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During the development of Karabas Nano, in December 2019, the prototype of the Buryak PI clone appeared. So, this initiative is based on the Nano. [»] . The designer of the machine is Sergej Belinski (i.e. tank-uk, Zaporizzja), the firmware is from Andy Karpov (andykarpov/Nikopol) and uses by the Chefranov Valentin Aleksandrovich (better known as TS-Labs, TSL; Ivano-Frankivsk) developed AYX-32 hardware emulator instead of the AY/YM chips. It consists of two cards, just like the Profi clones in the golden era. Here, of course, the PCBs are double-sided and surface-soldered, which are connected by two rows of pins. Thanks to this, the clone can be fitted into a Raspberry PI 3 housing, hence its name come from. 5. 1. Buryak PI 2020 For the October 2020 Buryak PI 2020 version, the processor is Z80, the control logic is hidden into the Altera EPM7512AETC144 CPLD. [»] From the two megabyte of SRAM, one is used by the Profi scheme and one is reserved for DivMMC in the clone. The image on the VGA output is already scaled in the CPLD. It has PS/2 keyboard, Atari and Sega joystick connectors. You can select from the 8 ROM banks of 512K with the F1-F8 keys. Scroll Lock activates the 7MHz turbo mode with LED feedback, Print Screen pauses the machine by stopping the CPU. The Wifi is based on the ESP-07 (or ESP-12) chip and works via the AY port. The clone has a cassette unit output and input. Three revisions are known so far. The first was released in July 2020, and the second revision was released on the following day. The third edition was published in September. (The first revision received continuous hotfixes.) [»] 5. 2. Buryak PI 2021 Buryak PI 2021 is a further development of the previous version, now based on the Intel/Altera EP4CE6E22C8 FGPA. It was presented before the Christmas of 2020. [»] This one is compatible with Pentagon timing and also supports the 14MHz non-wait turbo mode. The 21MHz mode is only there for testing purposes, because the peripherals would not be able to maintain this speed. Similar to the Karabas Nano, Z-Controller support has also appeared. The ARM Cortex STM32F405 microcontroller is responsible for emulating the sound as the Wild Sound II periphery. This section also contains the USB-RS232 UART port. As an added bonus, it also has SounDrive emulation. The 14MHz mode, activated by the Scroll Lock is indicated by flashing. F11 became the NMI button, F12 the reset, the Pause is the pausing one. The short list of errors can also be found in the repo. [»] ↑date: 2023/08
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több kép
2020/07. |
| UA-6. Pocket ZX on one chip |
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From Dnipro, Ukraine, zetalex appeared on the zx.pk.ru forum with his pocket-sized ZX clone in March of 2021. The 90x125mm sized 48K machine is built around a single chip, the STM32F103RET6 STMicroelectronics ARM microcontroller. [»] The heart of the 32-bit controller is a Cortex M3 processor at 72 MHz. This is accompanied by 512K FlashROM and 64K SRAM. With the 3.5-inch 320x240 resolution LQ035NC111 LCD and an 800 mAh battery, about 8 hours of operating time can be ensured. You can natively use .SNA files with the possibility of saving them on the SDHC standard, i.e. microSD card with a maximum capacity of 32 Gbytes. The sound of the beeper can be heard via a built-in speaker or a 3.5 mm jack. A potentiometer is available for this and for controlling the brightness. The accompanying 95x130x16.5mm 3D printed housing consists of two parts. ↑date: 2022/11 |
| UA-7. Pentagon 512 on Altera DE1 |
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From Kiev in November 2021, Z_E_V_S presented one of his old development. This firmware emulator is based on the terasIC Altera DE1 development board. It emulates the Pentagon 512 clone with AY-chip, and uses the TR-DOS 5.04T version as default. [»] The card is built around the Altera Cyclone II 2C20 FPGA, which is also responsible for simulating the virtual processor. The FPGA chip has 18752 logic gates and approximately 30K RAM. In addition, there are 8 megabytes of SDRAM, 512K SRAM, and 4 megabytes of FlashROM on the board. It also has a microSD slot, 4 microswitches and 10 two-position switches. Line-in and out, mic-in, VGA-out and RS-232 port can be also found on the board, to which PS/2 keyboard and mouse can be connected. For make it work, first you must burn the Altera DE1 ROM file found on the forum into the FlashROM. Then copy the Spectrum ROMs onto the SD card, as well as the .TRD, .SCL and .FDI files. F10 calls the service monitor. F1/F2 decreases and increases the volume, F12 is pause. Ctrl-Alt-Del resets the Z80 processor. The numeric keypad with left Crtl emulates the Kempston joystick. Switch number 9 is the normal/turbo selector, microswitch 0 resets both the Z80 and the Altera's virtual processor. ↑date: 2022/12 |
| ZX Spectrum 128K 10x10
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Harlequin clone from Ukraine The ZX Spectrum 128K 10x10 is developed by the KS Group in Kyiv. The 10x10cm size was chosen due to JLCPCB’s pricing policy: production costs increase exponentially beyond this size. The four-layer motherboard is based on the Harlequin 128K clone. The error-free rev 2.0 was released in September 2024. The goal was to create a basic ZX clone, which can be freely expanded later. The motherboard uses a mix of surface-mount and through-hole components. The CPU is a DIP-packaged Z80 for availability and easy expandability. The RAM, ROM, and the vRAM -latter is implemented in a separate circuit- are also DIP chips. The other components are SMT parts. For assembly and testing, it is worth checking out Aleksandr Karnauh’s (Александр Карнаух) YouTube channel, from through the firmware can also be downloaded. [»] The empty motherboard is typically found on the Olx.ua virtual marketplace. [»]
↑date: 2024/09 |
2024/09. |
| LT-1. ZX128 |
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The ZX128 is a Lithuanian development, which was unfortunately abandoned, there is no further news about it since July of 2007. Only the hardware part was completed from the machine, which is constructed on the basis of the Leningrad 1 clone expanded with some improvements compared to the original. [»] The clone consists of three cards. It includes a CPU-, a video-, and a ZX Flash/IO card. The keyboard card, originally conceived as a separate unit, was integrated into the one containing the processor. So at the same time, the machine was given the appearance of a traditional microcomputer. It also has a separate connector for the General Sound sound card. The latter expansion was not developed due to the low number of software support, as well as because of development time and costs. The design did not included optimization for mass production. As for specifications, the processor is 3.5MHz with 128K DRAM and 32K SRAM. In the latter could accommodate the different operating systems, which are loaded from the 64K type 27c512 EPROM. The image can be received via an S-Video or RCA connector, of course on a PAL system television set. The stereo music of the YM2149 is outputted through double RCAs and a jack. The joystick connector is works as Kempston, Sinclair 1/2 standards. The machine also has connector for traditional cassette tape recorder. The Flash/IO card has only been completed on a DIY card. It is based on the AT89C5131A microcontroller and has 512K RAM. The built-in SD card unit is accessed by USB protocol. ↑date: 2023/04 |
| LT-2. C4 Speccy 48K |
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Andrei Vatsenko (AndreiV01N) from Minsk was released in April 2021 the C4 Speccy 48K FGPA clone. [»] As its name suggests, it is built around the Altera Cyclone IV FGPA and emulates the 48Kmachine. The FGPA chip in this case is on an RZ-EasyFPGA card. The image is obtained in 1280x1024@60Hz mode through the VGA connector - due to the limitations of the card, it is only 3 bits without the Bright signal. The beeper is played via the built-in audio speaker, .TAP/.WAV files can be loaded/saved via RS-232 port. The keyboard connector is PS/2. By the way, the emulator is based on the ZX Spectrum 128K on Marshod2's code. [›] Considering the features, its May 2015 version was forked. ↑date: 2021/05 |
| DE-1. Aeon series |
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The Aeon was the clone series of Dmitriy Schapotschkin (ILoveSpeccy), who was originally Kazakh and then moved to Germany. Originally, it would have been named Neo, but the name was changed due to the appearance of the NeoGS sound card. The novelty of the open platform FGPA emulator is that the configuration can be changed without opening the machine housing. In this way, relatively simple emulation of countless 8-bit microcomputers is possible - including the lesser-known ex-Soviet machines. Members of the zx.pk.ru community actively participated in firmware porting and development. There is no information about firmware compatibility between the members of the series, most of the kernels are made directly for the Lite version, so they must run on it. The first two versions and the intermediate editions can be considered prototypes. The first version, Aeon 1.0, was released at the end of October 2008. [»] On the Sinclair product line, it emulates the ZX Spectrum 48K/128K and Pentagon 128K+AY machines using the T80 core. The emulated disk interface is DivMMC and it supports .SNA, .TAP, .TRD files. These are the constructor's own emulators from February 2009, other early emulated micromachines were ports of already existing projects. The PCB is single-sided for easy replication. The main components of the machine are the Xilinx Spartan-3 XC3S400 FGPA and the ATMega644 microcontroller. The price of the XC3S400 with 400K logic gates and 7K RAM was half the price of the competing Altera model, which is why the designer chose it. Since even with the 128K+AY+Beta-128 combo, the utilization of the FPGA was 44% and 12% of the ATMega644 resources was used, so this FPGA chip from 2003 was more than enough. It also includes an ATMega88 microcontroller. This makes it possible to reprogram FGPA and ATMega644 from Windows and Linux via USB or RS-232 port without opening the machine housing. (of course this is also possible from the internal JTAG connector). The FGPA can also be reprogrammed from the SD card, i.e. the firmware of the machine to be emulated can be loaded from it. The ROM of the microcomputer is loaded into the RAM from the SD card. So a special programming set is only needed for the ATMega88 and it needed only once. The mainboard has a VGA connector with 4096 color output. The keyboard and mouse connector is PS/2 ones. There is also a stereo sound output, as well as the outputs/inputs of the cassette unit is present. Instead of the originally planned one and a half megabytes of RAM, only 512K was made on the board, as this is more than enough to emulate all 8-bit machines. Aeon 2.0 was completed by the end of 2010, but was published for May 2011 due to the economical crisis. The Ethernet connection seems to be its most important innovation. [»] The new generation, Aeon Lite, was ready for February 2014. Here the FGPA is the Xilinx Spartan 6 XC6SLX9 on the 90x120mm board. This FGPA has 9152 logic gates and 576K RAM. [»] The size of SRAM on the card itself can be 2x512 or 2x1024K. The PIC24F microcontroller controls the platform. In addition to serial, USB and SD cards, firmware can also be loaded from FlashROM using this microcontroller. The PCB was designed for the KGB named box, which is available in several colors. The VGA out here also provides 4096 shades, the sound is also output via a stereo 3.5 jack. One PS/2 port is soldered for the mouse and keyboard, so a Y-cable must be used. There is also a double PS/2 connector on the front for NES/SNES controllers. Here was choosen the PS/2 standard to save space. Power can be supplied via a 6.5-9V DC adapter or a USB port. The completion of the Aeon also done at the same time, but its specifications allow the emulation of 16-bit microcomputers in theory. It seems, that only a few pieces could have been made from it, and its support is completely missing. In any case, Aleksej Alekseenko, aka ZXAAA, must have a copy of it in the Russian capital... The FGPA here is Altera Cyclone III EP3C16Q240/EP3C25Q240 (15,408/24,624 gates, 64.5K/76K internal RAM). The microcontroller is the PIC32MX695F512H type. Other features are the AC'97 Audio Codec (ALC655) chip and 2xUSB Hosts. It has 2 megabytes of SRAM and 32 megabytes of SDRAM. The size of the I2C EEPROM is 64K, the FlashROM is 32000K. It also has a real-time clock. The 18.2x13 cm PCB is sized for a Hammond RM2055S enclosure. Since the project is completely open source, several people have started small series production, such as MVV or Paul. A floppy/HDD emulator was also created based on the machine, named to DREM (DRive Emulator). This was created by kapitan-u who ported the Lviv PC-02 kernel for the system. The creator and his company are currently based in Vancouver. [»] ↑date: 2023/01 |
| DE-2. AX82 |
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Jörg Wolfram's (jwolx) third Sinclair clone is the AX82 from Munich. It is also the first one to use a CPLD in addition to the AVR microcontroller. His first machine was only compatible with the ZX81, the second was already partially with the ZX Spectrum. The CPLD made possible the full functionality. [»] On his website, you can also find many other projects based on microcontrollers and CPLDs. [»] The controller of the AX82 is an Atmel AVR ATMega 644P type microcontroller. It is connected to the Xilinx 9536 CPLD and 2x32K cache RAM. The other components are passive circuits and connectors. These includes VGA, TV-RGB/Scart, PS/2 keyboard ports; SD card and Kempston compatible interface adapter. The ATMega 644 is an 8-bit microcontroller, originally runs at 20MHz, but in this project overclocked to 24. It has 4K SRAM, 64K FlashROM and 2K EEPROM. The 16K Spectrum ROM is also located in the total of 64K external RAM - of course in a write-protected area. Using a TV, the speed is the same as the original Spectrum, 87% with VGA. With a 32MHz microcontroller, 100% speed on VGA would have been possible in principle. Unfortunately, the beeper is not emulated. SD, SDHC and MMC cards are supported by the FAT16-based file-system using tape images. In addition, it is possible to save and load snapshoots. It also includes a built-in monitor program. The PCB is single-sided, using a mixture of through-hole and surface-mounted components. Firmware dates are 01 October 2012 (v0.32) and 07 August 2014 (v0.35). The most important innovation of the latter is the Kempston interface. In addition, this version is characterized by minor bug fixes, improvements and revision in the documentation. He began developing the AX82B in June 2013. It is based on his self-built AVR-based computer made around the ATmega1284P. It did not include external RAM or CPLD. It could load and save Speccy programs from/to FlashROM up to 15.5K RAM. The capacity of the FlashROM here is 128K and there is also an insignificant 4K EEPROM. It would also support SD cards and external Flash. Unfortunately, the machine with Cyrus Chess burned in was not further developed. That's because only one person was interested in it: David Roper (aka RetroGadgets, Sheffield). He, on the other hand, started to implement his own AX82 clone under the name ZAX-48 at the end of 2016/new year of 2017. Here the power supply, VGA, joystick JTAG and SD slots were already integrated onto the PCB. The community bug-fixed motherboard was ready for next month. After a short break, it gained its final form in September 2019, returning to the original AX82 name with 14 new bug fixes. ZAX-48 was also cloned by Pavel Ryabtsov (aka Paul; Kineshma). [»] ↑date: 2023/01 |
| DE-3. ZX Spectrum 48K on STM32F429I |
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The mikrocontroller.bplaced.net page contains the source codes of projects made in C language for ATMega, STM32 and XMC2Go microcontrollers. Its author was Uwe Becker, i.e. derexp. The site was reconstructed by his brother, Manfred, so that projects that once disappeared in the past became again available. These include the ZX Spectrum 48K on STM32F429I. The final version 1.1 was published by the author on January 30, 2014. [»] The firmware emulator was created for the STM32F429I-DISCO board, but of course it also works on its successor, on the STM32F429I-DISC1. The microcontroller of the board, which is integrated with QVGA resolution and 2.4-inch LCD is the STM32F429ZI. It contains a 32-bit RISC Core M4 processor running at a maximum of 180MHz, and contains 256K SRAM and 2048K FlashROM. You can also find 8 megabytes of external SDRAM on the devices. There are also 2 micro AB connectors, one of which is debug; the other can act as serial connection and a mass storage port. It contains six indicator LEDs, 2 of which can be freely configured. One of the two microswitches is reset, the function of the other can also be defined by the user. Of course, the system bus can also be found on the boards. The source is from Marat Fayzullin's Speccy emulator. The USB PC keyboard can be connected via the card's USB port. The Kempston joystick is emulated by using the cursor keys and right ALT. It supports the .Z80 file format, which can be loaded/saved from/to the PC through UART. Two games are pre-installed in the FlashROM, in addition to these, the user can of course also burn others. You can listen the beeper by connecting it to a specific pin of the system bus. The source code of the project is freely downloadable. ↑date: 2023/03 |
| DE-4. Steccy |
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The Steccy firmware emulator also runs on the STM32F407VET microcontroller and an LCD combo. However, it already has Linux and Windows and Raspberry Pi ports. It is the creation of Frank M from Germany, who better known in the online hobby electronics community as UKW or UKW 100. All features and community bugfixes are documented excellently [»]. Partly on the author's GitHub [»], partly on the Mikrocontroller.net German site [»], the informations can be found in English and German. The system emulates the ZX Spectrum 48K and 128K models. It can simulate all documented and undocumented instructions of the Z80 processor by ticking the clock signal similar to the original. ULA emulation is optimized, only the changed screen content is copied from system memory to video RAM, not all of it. The 48K and 128K, possibly alternative ROMs can be stored on the card's FAT32 file system SD card. This is also where .TAP, .TZX and .Z80 files are located. Unfortunately, the system only handles 8+3 file names. By the way, the author recommends the use of .TAP files, since they are definitely based on the factory ROM routines. In the case of TZXs, 5% of them may have compatibility problems - this is recommended to be loaded into Fuse emulator and converting them. The .POK files with the same name can be loaded alongside the tape files - facilitating the use of cheats. Regarding LCDs, the system supports the units with ILI9341 and SSD1963 controllers. The parallel bus is required for operation, the touch screen is an unused function. The advantage of the 3.2-inch ILI9341 display, is that it can be attached directly to the card. However, with their larger dimensions, the SSD1963, 5- and 7-inch pieces provide more enjoyment. In addition, they can also be connected directly with the adapter designed by the author. The firmware emulator only works with the 800x480 resultion ones. Here we get a magnification of 2:1, which means 512x384 pixels with a border. Since the background lighting consumes 400mA, it is advisable to use an external power supply. In this case, the 5-volt can drives the card and the screen together. Regarding the keyboard, ZX-matrix, PC/PS2 and USB keyboards can also be connected. It is possible to use all three at the same time, which is useful in multiplayer mode. F1 is the rotation of the LCD image, F2 is the RGB-GRB switch, F3 switches to the full Z80 speed, which the card can handle. That's roughly five times that of the original Spectrum. On the Linux variant, F12 stops the machine. The USB keyboard is connected to the card's microUSB port, in the other two cases to the row of pins. For older version (v2.0) cards, the microcontroller must be modified a bit to use the USB keyboard. Sinclair 1 and 2, Kempston and Cursor joysticks can be emulated on the PC keyboard. The numeric pad, and also the number keys on the top row can be used for this. The Wii Nunchuk and Wii Gamepad controller, and of course their clones can be also used. By the end of March 2021, the author had developed a circuit diagram to convert the ZX Spectrum keyboard into a PS/2 keyboard. All it needs is an STM32F103 'BluePill' microcontroller. [»] Those who intend to put the clone in a compact box, can also find circuit diagrams of small amplifiers from the author. ↑date: 2022/11 |
| FR-1. ZX Spectrum 48K on Bitbox |
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The Bitbox console released in February 2014 [»] is the project of Xavier Moulet (makapuf) living in Rennes, France. The open source, DIY project built around a single chip was inspired by the Uzebox 8-bit console. The constructor created a more powerful 32-bit console, of which the first revision was published in September 2013. [»] Beside the mini-applications, games and emulators were also created for the machine. For the final version, rev.2, the PS/2 connector was replaced with double USB, stereo sound instead of mono, the 12-bit VGA-out was further developed to 15-bit and the appearance of the UEXT standard port distinguishes it from its predecessor. Regarding other specifications, the machine, which is implemented on a 6.5x5 cm board, based on a single microcontroller chip, the STM32F405. Inside it, the ARM Cortex-M4 processor can run at a maximum of 168 MHz, and it also contains 192K RAM and 512/1024K FlashROM. VGA out defaults to 640x480 resolution at 60Hz. The sound is outputted via a stereo 3.5 jack. The programs can be stored on a microSD card. The system receives power via microUSB, and according to the documentation, this port can also act as a standard USB and can be used for firmware updates too. There is also a pair of pins (or at least their place) for a separate power source. In addition to the reset, it also has a freely definable microswitch. Next to the power LED there is an user LED too. The console has an SWD debug port too. The ZX Spectrum 48K emulator was released in May 2015. This is based on Uwe Becker's modded emulator [›]. In addition to the realized working features, plans included the implementation of sound, turbo on/off, the possibility of loading/saving from/to a microSD card, including programs and screenshots, as well as gamepad support. It seems that the entire Bitbox project is stuck in the 2017/2018 turnround... In any case, it can be ordered for under 40 dollars in the designer's Tindie shop for those who want a ready-made one. [»] ↑date: 2023/03 |
| BE-1. Jean-MarcHarvengt |
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In the Brussels living software engineer, Jean-MarcHarvengt coded for the Atari ST back in the old days. Since the last years, he is an active member of the forum of pjrc.com company, which mainly deals with development cards and their accessories. It is no surprise, that most of his firmware emulators run on the company's Tensy series. He was ported existing projects to a wide variety of development cards. The abbreviation TeensyCEC stands for Console Emulators and Computer, which is based on the Tensy 3.6 development board. The construction started in August 2018. The 3.6 card is built around the MK66FX1M0VMD18 microcontroller from the NXP Semiconductors company. Its CPU is the single-core Cortex M4F 32-bit ARM RISC processor clocked at 180MHz (240MHz overclocked). The microcontroller supports the processor with 256K RAM, 1280K FlashROM, 4K EEPROM, as well USB and SDHC standards. The Tensy 3.6 development card contains the physical ports for this. This firmware emulator simulates 8-bit consoles and microcomputers. Latters were integrated after the development of the microswitch keyboard module. In order for the minimum configuration to work, in addition to the development board, a touchscreen LCD with an ILI9341 or ST7789 controller, an analog joystick and 3 microswitches must be purchased (fire button, reset, user1). This can be expanded with an uVGA module enabling the connection of an external monitor, a digital joystick and three additional user-definable microswitches and a keyboard. The keyboard is controlled by the ATmega328P microcontroller. The emulation of different retro hardware is realized at different success, as the author mostly ported existing projects - as was already told. The ZX Spectrum emulator completed by September 2018 supports the 48K+AY configuration with a partial beeper implementation. The system can handle .SNA and .Z80 files, but the latter does not work perfectly yet. A Kempson joystick can be used for control. The OSD keyboard is sometimes stuck, but fortunately there are no such problems with the microswitch keyboard. The continuation of the previous project is espMCUME, i.e. Multi CompUter Machine Emulator based on ESP32. Since it is only a porting of the previous project, February of 2019 was enough to complete the whole thing. The author implemented it on the NodeMCU-32S development card from the Ai-Thinker company. Its central unit is the manufacturer's ESP32-S microcontroller. Since this is a clone of the original ESP32-WROOM-32 microcontroller from Espressif Systems, its specifications are also the same. So it has a 32-bit Xtensa LX6 dual-core processor with 448K ROM and 520K SRAM. The clock signal is between 80 and 240 MHz. The built-in FlashROM is 4 megabytes. You can use 8 megabytes of external SRAM and 16 megabytes of external FlashROM. The mini-config here is also a combo of this card, the LCD, the analog joy and the 3 microswitches. The project supports only the ILI9341 controlled LCDs, as the development board does not have SD card port. The microswitch keyboard can also be connected to the configuration. The ESP-32 Wrover and its clones with built-in 4/8 megabyte PSRAM (i.e. external SRAM chips) could theoretically expand the range of emulated hardware, but the speed of this processor is the barrier. So they are slow. That is why the next generation, the TeensyMCUME family, is based on Tensy 4.x cards, which also enables the emulation of 16-bit microcomputers. The virtual ZX Spectrum is of course also present here. The development started in March 2019. Tensy 4.0 is also based on NXP's microcontroller, this time around the IMXRT1062DVL6. Its processor is a 600MHz Cortex-M7 that can be overclocked up to 912MHz. This already communicates in 64 bits with the 1024K RAM. It has 1984K FlashROM and 1080K emulated EEPROM. The USB and SDHC support required for the emulator is of course also present here. Tensy 4.0 with 8/16 megabytes of solderable PSRAM expands the range of possible emulated hardware by a few consoles. Its successor board, the IMXRT1062DVJ6 microcontrollered Tensy 4.1, has 7936K Flash memory and 4284K emulated EEPROM. Expanded with PSRAM, it emulates the most hardware from the author's works. As with version 3.6, the image can be outputted to VGA for the 4.x versions as well. The microswitch keyboard used there is also compatible. In April of 2021, the project was also ported to the Raspberry Pi Pico microcontroller panel. The RP2040 microcontroller has a 133MHz dual-core ARM Cortex-M0+ CPU and 264K SRAM. Supports 16 megabytes of external FlashROM. It also only emulates 8-bit microcomputers and consoles - worth to mention, for the C64 had to be overclocked to 250MHz. The T-Computer (ie Tee-Computer) is based on version 4.1, and it development was began at 2021 September. The release date can be regard as June 2022, when the motherboard arrived and the first hand-soldered computer was assemled.It has a 42-key keyboard along with a three-button D-Pad. There are also two predefined buttons. The built-in LCD has a resolution of 320x240 and also has a VGA output. The sound is 16-bit stereo. In addition of USB, there is also a DB9 joystick connector. It can be operated from either USB or LiPo batteries. ↑date: 2022/12 |
| SK-XX. Peter Misenko |
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Peter Misenko (bobricius) is an independent hardware developer from Sarisske Dravce, Slovakia. Development cards such as PicoDuino, Winxi and Mini Dixi are associated with his name. In addition to these, he also produced various LED watches.
He is the owner of PeMi Technology company. The special feature of his electronic products is that the PCB is not only the motherboard of the devices, but also their housings. Another interesting thing is that the location of the buttons, switches, and LEDs are also perforated, thus simplifying the production. By the way, the PCB is also functioning as a load-bearing element. Regarding his retro-computing things, their basis is the Armachat communicator. Misenko developed this for post-doomsday communication. Its central unit is a Raspberry Pi Pico (or clone) card. This is connected to an LCD display, a microswitch keyboard with optional backlight and a radio transceiver unit. The project was sparked by the chip crisis. The automotive industry is not interested in Pico - that's why it was chosen. The number of other electronic devices installed is also minimal, everything is implemented within the Pico. For retro computer emulators, you only need to replace the radio unit with a microSD slot and add a piezo speaker to the system. The clone series is under continuous development. It is practically untraceable to identify the individual revisions. What is certain, is that during the development, the constructor already begin prefers the Pico-compatible unit of the Waveshare company, the RP2040-Plus when designing. It already has a USB-C connector and supports the charging of LiPo batteries. Thanks to this, the newer versions now have batteries, which are located on the back panel. The original Pico is based on the RP2040 microcontroller. It features a 32-bit RISC Arm Cortex-M0+ processor running at maximum 133MHz with 264k SRAM and 2048K FlashROM. The WaveShare RP2040+ type, in addition to having the already mentioned USB-C connector and Li-Po charger, also has a larger optional FlashROM, which can be 4MB/16MB. On top of all that, the power supply circuit has also improved - so it is a really logical choice instead of the original. Regarding firmware, all machines can use the MCUME emulator by Jean-MarcHarvengt and Phil Scull's (aka fruit-bat) pico-zxspectrum. In the first case, we get a multi console-micro emulator. The second one is specifically compatible with ZX Spectrum 48/128K, of which functionality is much more complete. In the original PICOmputer, which was released in April 2021, the display is a 240x240 pixel resultion, 1.3 or 1.54-inch IPS unit with ST7789 controller. Here, the horizontal resolution of the LCD is clearly the biggest obstacle to faithful retro emulation. The size of the motherboard - and thus the machine as well - is 10x6.9 cm. With the PICOmputer MAX in August, a display and a front panel replacement solved the former problem. It has a two-inch, 320x240 pixel screen placed in the center. The PICOmputer BOX is the revision of the previous on a 10x10 cm motherboard, which has a three-sided enclosure from November. The PICOmputer ZX is a special variant of the first PICOmputer, where the screen resolution is adjusted to the original Speccy. In this case, it is a 1.69-inch, 280x240 resolution unit with rounded corners. The constructor appeared with the machine in April 2022. The PICOmputer V is a notebook-like design from November. In February 2023, a version with a 2.8-inch screen was released under the name PICOmputer 28. The machine is now closed on all its four sides. Another branch of development is consoles that can be connected to VGA monitors, which started with retroVGA v1. The firmware here is supplemented with Miroslav Nemecek's PicoVGA library. In addition to VGA-out, the 10x10 cm console, released at the end of December 2021, also has a joystick connector. For the PICOmputer gamers edition from March 2022, the hardware was practically integrated into a joystick, leaving an integrated small keyboard. The 20x10 cm PICOZX is the version of the retroVGA with a keyboard compatible with the ZX Spectrum, which also received some special menu buttons from August. The 'console with keyboard' design has been replaced by a shape reminiscent of a traditional microcomputer. The second version of the original console is October's retroVGA v2. This was also made with the traditional microcomputer proportions (17.5x7.5 cm). From the end of November, the PICOmputer TOUCH has 3x10 backlit touch buttons. Into the 13.6 x 8.8 cm, 1.6 mm thick PCB fits neatly the LCD with the same thickness. By the way, this display is the 1.69-inch, 280x240-pixel display already known from the PICOmputer ZX. The PICOZX handheld was created in March 2023 by merging the two series. With the proven 2.8-inch LCD, cursor buttons and piezo speaker, we get a portable console. Using the VGA and joystick ports and the 3.5 audio jack-out, you can play with a home retro console. ↑date: 2023/03 |
| AU-2. Speccy2021 |
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The Speccy2021 firmware clone is inspired by Speccy2010. It is based on the Diligent Arty Z7-20 development board. The code is the work of the Russian originated Dmitry Pakhomenko (magictaler). [»] The developer is currently the co-owner, electronics engineer and software developer of the Sydney-based Magictale Electronics. By the way, the company's profile is the development of embedded electronic systems for third party customers, along with writing of firmware and software as required. The Diligent Arty Z7-20 development board is based on the Zynq-7000 system-on-chip. Its main components are a 32-bit, 650MHz Cortex A9 dual-core processor with 256K RAM and a Xilinx XC7Z020-1CLG400C FGPA. The latter has 85,000 logic gates and 630K internal memory. The card itself contains 512 megabytes of DDR3 memory and 16 megabytes of FlashROM. As for communication ports, there is gigabit Ethernet and USB 2.0 on the board. The JTAG required for programming the FGPA as well the UART are on the same type B microUSB. The picture and sound are outputted via HDMI port or by the built-in mono amplifier through a 3.5 jack. The card is also includes a HDMI input. The Arty has four microswitches, two piece of two-position switches, two RGB- and four traditional LEDs. In addition, there are red reset and power-on reset buttons. The external storage is a microSD card. The voltage required for operation can be obtained from USB or from an external 7-15 volt power supply. SPI and Ardunio/chipKIT connections can be done via female pin headers. In addition to the microUSB, FGPA ports can be also find on pin connectors. The firmware emulator can upscale the original ZX Spectrum screen in multiple resolutions through the HDMI. It emulates both 48K and 128K Spectrums, although not at 100% hardcore level. The keyboard can be connected by the USB port. The beeper and AY-chip music can be heard on the Arty's mono amplifier. Through the FAT16/32 file system of the microSD card, we can load .TAP, .TZX and .SNA files using the built-in shell program. ↑date: 2023/04 |
| ZX Spectrum +3e/+2e |
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ZX Spectrum +3e is not a completely new machine, but the "enhanced" version of the last official Spectrum, named +3 (must note, that the black +2A and 2B are also can rebuild to +3e, more exactly to +2e, as they have the same mainboard). This machnine is the inventment of Garry Lanchaster from Spain. Two new modifications were introduced with this machine. Firstly, the new +3e ROM, and secondly, the possibility of connecting hard disks and Compact Flash cards. The original +3 ROM was bugfixed, as well extended with new Basic commands. With this, for example, .SNA .Z80 files downloaded from the Internet are directly usable on original Spectrums. These new ROMs are even offered on sale, for owners who are affraiding of the task of burning EPROMs - others can download the ROM image files from the Internet either in English and Spanish language. Second phase of tune-up is building the IDE interface. In 2000, was a relatively new idea to connect hard drives to the ZX Spectrum. Only Putnik's 8 and 16 bit interfaces were existing. +3e was using the simpler, 8 bit version. Pera's interfaces also will detailed later. Going through the years, number of IDE interfaces were quickly increased, and this machine also begins to support them. And it is also works fine with Compact Flash cards, which are more popular nowadays. The Polish Jarek Adamski also get interested in the +3e tuning, and did not wanted to leave out the owners of older machines. That is why he developed the PL3MEM card, which can tune up the 48K/128K/128K+2 and TC2048/2068 machines. Details will come later, Jarek's developments worth a dedicated section. Until the native support of CF cards was not ready, owners could choose the construction of Jose Leandro Martinez Novellon or Aitor Gomez Garcia from Spain, which will also described later. One of the members of the hw.speccy.cz team, Ik0n has further developed the original idea as ZX Spectrum +3e^2. Here, with a switch, we can choose between regular +3 and + 3e modes. At the moment it is compatible with Pera Putnik's 8, 16 bit and CF interfaces, Sami Vehmaa's ZXCF(+), ZXCF+2, ZXMatrix cards, the divIDE(+), MB-02+ and MB-02+IDE interfaces, the ZXMMC and ZXMMC+ expanders as well Jarek's Yamod.IDE8255 controller and certainly with the PL3MEM card, which is contains the previous controller as standard. Philip Mulrane was also integrated it into his ultimate +2A/2B floppy interface. The success of the concept is indicated by the fact, that its FGPA emulation was also released by Alessandro Dorigatti. He was integrated the ZXMMC+ system into the Turbo Chameleon 64, V6Z80P és MCC-216 'consoles'. After some tuning, the already mentioned Jarek Adamski’s Yamod.ATBUS interface also can simulate its operation by the interface of Pera Putnik. About these things we will read later. |
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| ES-2. ZX-Uno |
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The birth of the original ZX-Uno The idea of the ZX-Uno arose in 2013 end of July on the zonadepruebas.com forum with the aim of creating a cheap ZX Spectrum clone. [»] About 40 prototypes were made in four versions before reaching the final official version 4.1 in February 2016. The motherboard measures 8.56x5.6 cm and can be mounted into the housing of a Raspberry Pi 3 B+. The Spectrum community also contributed to the development. New cores, software, cases and accessories were created, and some individuals even redesigned the motherboard according to their own needs. In addition to the standard ZX Spectrum features, it also has an expanded ZX emulation. Furthermore, it is capable of emulating 8-bit microcomputers, consoles and arcades. Among the members of the development team, Antonio José Villena Godoy (avillena) is the initiator, president of the non-profit ZX-UNO Developer Association (AZXUNO). He is also the developer and maintainer of the BIOS, the designer of the schematic and the distributor of the prototypes. Jordi Bayó (Hark0) is the secretary of the association. He is responsible for the design, web design, packaging and keyboard stickers. Samuel Baselga López (Quest) has carried out numerous non-Sinclair core ports, mainly consoles and arcades. He is also responsible for the framework system, which allows the FPGA reprogramming without a JTAG programmer. He also participated in the development of the prototypes. Miguel Angel Rodríguez Jódar (mcleod_ideafix) is the treasurer and PR manager, as well as the developer and maintainer of the ZX, SAM, Jupiter Ace and CPC cores. The only member, who is not living in Spain is Watchara Chantang, also known as Don "Superfo," who was the designer of the first three motherboard versions, originally from Taiwan and now living in California. The central unit of the motherboard is the Xilinx Spartan XC6SLX9-2TQG144C FGPA with 512K SRAM. The FGPA has 72K internal BRAM, 11K distributive RAM and slightly over 9 thousand logic gates. The serial flash is a 4 megabyte Winbond W25Q32BV type. In terms of connectors, the image is outputted by an RCA and a 9-pin Molex connector. Both the EAR and sound out use a 3.5mm jack, the latter being stereo. The keyboard is PS/2 standard and the clone accepts standard Atari joysticks. The power connector is microUSB. The SD card slot is located on the bottom side of the motherboard. The connectors, except for the cassette unit, are placed in such a way, that the board can be built into a standard Pi case. The JTAG programmer connector has 6 pins and the expansion slot has 3 rows of 12 pins. The crowdfunding campaign started in February 2016 and concluded in mid-March, a records breaking time. The motherboards were ready by August. With an amount of 18,000 Euros, 400 motherboards and 52 cases (from modified Pi cases) were made. The machines were released with the ZX Spectrum core and the OpenSE ROM developed by Andrew Owen. The product was published under the CC-BY-SA-4.0 license terms. Therefore, it is freely licensable, distributable, usable, modifiable, and can even be commercially released as a new, modified product – of course, with proper attribution to the source. Superfo's clones Slightly stepping back in time, in August 2015 the ZX Uno A+ was released and can be considered as a v4.1 compatible pre-series version, which can be installed in the Raspberry A+ case. This version is between the second and third prototype. A 10-piece mini-series was made from this version. [»] It comes with 2 megabytes of RAM and an integrated VGA output. As for storage device, MicroSD is used. The EAR is outputted through a 2.5mm jack. The PAL composite and audio out are through a shared stereo 3.5mm connector. The keyboard protocol is PS2 standard with a USB port, so it requires a dual USB/PS2 keyboard or adapter. Its further development is the ZX Uno A++, for which on a full-sized add-on card would placed the Ear, Joystick and HDMI connectors. The first mention of this version is from November 2016, and the date of the circuit diagrams is also the same. [»] The designer refers to it as the "last version A+" variant, while the forum members later named it to A++, which was adopted by the constructor too. [»] The Pocket ZX-Uno was appared on the ZX-Uno forum in October 2017. [»] Superfo made a PCB for fitting it into the Ben Heck portable case. In addition to the main board, an Arduino Mini is required for controlling the keyboard. Furthermore, a battery+charger controller, an amplifier+speaker, and of course a 3.5-inch LCD are needed. In addition to the 40 keys, there is a dual-fire button joystick, NMI and Reset microswitches, as well as a power switch in the machine. The PCB was designed so, that the physical connectors of the Uno can be accessed by drilling the computer case.
ManuFerHi's variants Manuel Fernandez Higureas (aka manuferni) from Terrassa also has joined to the development of ZX-Uno variants. The circuit diagram of the ZX Uno VGA, which is released in August 2016, is the same as version 4.1, but uses more durable components and has rounded PCB edges. The 512K SRAM module has been integrated onto the motherboard. This helped eliminate the image noise caused by the use of an external 2 MB module (due to signal loss of longer PCB traces and the interfences of the pins of soldered connectors). [»] The VGA connector is of course present, and it has a bonus reset button too. The designer also created an acrylic case, which is counts his trademark. The ZX-Uno VGA 2M version was announced in February 2017 and the first batch was ready by the following month. [»] In addition to the VGA connector, it has a 2 MB SRAM module. The main novelty is the dual joystick port. The flash memory capacity has also increased, using the W25Q128 module, now allowing a maximum of 32 MB. The 9.2x7.7 cm board size includes two user-definable microswitches alongside the reset button. The expansion pin header has been removed, and power can now be supplied not only via microUSB but also by a jack. As usual, an acrylic case has been made for the motherboard, which is equipped with a push-push SD slot. The ZX-Uno VGA 2M model was announced in February 2017 and the first series was already completed by the following month. [»] In addition to the VGA connector, it has a 2 megabyte SRAM module. Furthermore, the dual joystick port represents the main novelty. The flash memory size has also increased, with the W25Q128 module, now reaching a maximum capacity of 32 megabytes. Alongside the reset button, the 9.2x7.7 cm-sized board also includes two freely definable microswitches. The expansion pin row has been removed, and power can be supplied through both microUSB and jack connectors. As usual, an acrylic case was made for the motherboard, which has also received a push-push SD slot. The ZX Go+ [»] is a ZX Uno 4.1 variant that can be installed into a ZX Spectrum 48K/48K+ (replica) housing. It is designed to be used without any modifications on the case. The clone was ready for 2017 June. To the place of power supply jack there is the PS/2 connector. On the place of the edge connector was placed a microUSB for power supply, a custom expansion port, a reset microswitch and a microSD slot. The joystick port peripheral card, which can be connected via this custom expansion slot, later became standard addition for all motherboards. In addition to the joystick port, this enhancer card also features a VGA output, a reset and Arduino inputs. Therefore, it is not surprising that a combined joystick+VGA card is available for it. The MIC/EAR jacks remain in the same position. The MIC jack also serves as the audio out connector, so external speakers can be connected to it, which also mutes the optional internal speaker. The TV output is replaced by a 9-pin miniDIN connector, which is originally RGB-out standard. Optionally, composite output can be requested, in which case the empty pins on the connector are used. Unfortunately, this may affect the original RGB image quality in some cases. For those who don't mind modifying the housing, the joystick can be installed to the left of the MIC/EAR jacks, and the SD card slot can be installed to their right. These additional cutouts can (could) be ordered through RetroRadionics, the supplier of the housings. Anyway, the joystick port is not an extra, second port, but a lead-out from the expansion port. Regarding the internal connectors, the two connectors of the keyboard membrane are present, of course. As the VGA/joy card, the original ZX-Uno 4.1 expansion port is optional. If accessories are used, the same pin on the ZX Go+ expansion slot and the ZX-Uno expansion slot cannot be used by both expansions, as it can damage the FPGA. The JTAG and ICSP/USB headers necessary for programming the FPGA and ATmega are also included. It is also possible to use an alternative reset button, such as the original reset button on the 48K+. There is also an NMI button for enthusiasts. Optionally, the motherboard can be requested with 2 megabytes of RAM.
Versions of 8bits4ever The ZX-Uno (M) was released in October 2016 by the Barcelona-based retro technology company 8bits4ever. [»] On the 10x8 cm motherboard, some changes were made compared to version 4.1. It has standard VGA connector and stereo RCA audio output. Power can also be supplied via a jack, the microJST JTAG connector was replaced by a pin row. The machine also got reset and power buttons. At the same time, a 3D printed case was made for it, following the black and red color scheme of the ZX Spectrum. ZX Uno (XL) is the version, which can be installed intp Spectrum 48K/48K+ or replica cases. [»] So the keyboard ribbon cable connectors are certainly also present on the motherboard. In addition to these, there is also an internal JTAG port connection. The power supply connector is located in the original Spectrum's power supply connector location. Starting from Issue 2, it is polarity insensitive and can handle any voltage between 7 and 28 volts (although the system prefers 7-9 volts the most). Near to this, there are the power and reset buttons, as well as an expansion bus and a microSD slot for storage. The stereo audio out and cassette unit input are located in the location of original EAR/MIC. The TV output is replaced with a PAL composite out. To integrate the optional PS/2 keyboard or Atari joystick connections, the casing needs to be cutted. For those, who do not wish to do this, it is possible to connect an external expansion unit, which includes a VGA connector as well. In addition to the universal power supply connector, starting from Issue 2, a new type of expansion slot was introduced to. Another novelty is the MegaDrive 2 compatible RGB output on the upper left side. The latest versions of the motherboard are equipped with 2 megabytes of SRAM instead of 512K. The size of the FlashROM is 16 megabytes. The Issue 2d motherboard is also available from Paul. According to feedbacks, the RGB output is buggy, it needs to be modded for correct operation. [»]
Improvements by the mastermind Villena Villena's first development is the unofficial ZX-Uno v4.2 from April 2017. In this case the JTAG microJST connector has been replaced by a pin of rows, and the circuits of PS/2 and joystick was changed. [»] At the same time, the creator started to made much more attractive acrylic housings instead of Cyntech Components' housings, which were already available in his webshop in June. The idea of constructing ZXDOS came up for Villena in May 2017. He bought an FGPA card on Aliexpress and started modding it to ZX-Uno. So, he replaced the SDRAM with SRAM, changed the type of FlashROM, and added some connectors to the card. Later, McLeod and Quest bought similar cards and they also started experimenting. The second prototype was compatible with the ZX-Uno Jamma add-on, i.e. focused on the arcade implementation. Neuro, who also joined to Villena, immediately made some arcade cores for it. ZXDOS was created from the third prototype. In addition to Neuro, the development team was later expanded to include Mcleod, Kyp, Distwave, Yombo (Juan Jose Luna Espinosa) and Jepalza (Juan José Epalza). The official launch date is September 2018, the machine itself was completed by the end of August. [»] This clone has a modular design. The main motherboard contains the XC6SLX16 type FPGA, the MT48LC16M16A2 type 32 megabyte SDRAM memory, also the 32 megabyte FlashROM and a second jack power connector. Compared to the original Uno, the FGPA has more logic gates, slightly more than 14,500. The size of BRAM is also 72K, that of distributed RAM is 17K. The upper addon card contains the VGA connector, a 3.5 mm stereo jack audio output, 512K SRAM, double joy port with 2 fire buttons and the JTAG interface. The optional composite output can also be placed here. The PS/2 mouse and keyboard sockets, the microSD slot, the power button and the main microUSB power input have been placed onto the lower expansion card. The optional EAR input can also be soldered here. Later, at the end of the year, the machine also received an FGPA trainer card. Of course, a Villena-style acrylic machine housing is also ready for the clone. The construction of the microZX1 clone was started three years after the original project. The first pieces were made in February 2019. [»], [»] Some completed prototypes have been released for sale in his webshop. [»] The clone, which is planned to be put into serial production by crowdfunding, would have been a small machine with standard cables. The start of financing action was March 2019, and unfortunately by the end of April, it was revealed that the initiative had failed. [»] The size of the board is 4,5x5,4 cm. Video output is VGA, which can easily be converted to SCART with a mini PCB. The RAM size could have been either 512 Kbytes or 2 Megabytes, the size of the FlashROM, if all were true, 32 megabytes. The storage is microSD, the composite output is gone. The constructor wanted to make a series of 100 pieces. He ordered a 10-piece prototype package, eight of which were intended for community testing. In addition to the VGA-SCART converter, he was also designed a VGA-composite converter PCB - both of them are also compatible with the original ZX-Uno. Seems, the EAR signals are on the unused pins in the VGA connector in both cases, and the composite converter also has a mono audio output. A joystick splitter card was also created for the clone. All above that, a very interesting addition was born, which turns the device into a combi DivMMC+SCART interface. In early April, the second revision came out, which already included the EAR input on the motherboard. This has the improved Superfo circuit compared to the original ZX Spectrum. Later was made an acrylic housing for it. The +Uno v1 is a 2-megabyte version from July 2019, which can be installed into the 16/48K (+) and replicas housings. [»] The original power supply socket is replaced by a microUSB power input and power button. Behind the standard edge connector, there is a microSD slot, and then the USB mouse and keyboard port surrounding the JTAG pin slot. Beside the audio out, the Superfo tuned EAR connector is soldered. As for video output, on the one hand, a VGA/SCART compatible Ethernet connector is used, which unfortunately requires of cutting the housing. The main video connector is the composite output at the original TV-out location. The built-in stereo speaker pair can be controlled by separate potentiometers. For those, who want to install the motherboard into their own machine house, besides the ZX Spectrum keyboard membrane connector, there are holes perforated for Cherry MX microswitches. Later it also received a smoke-colored acrylic microcomputer case. The ZX Uno+ was ready by July 2019. [»] Villena made this for those who missed out on the original series. The circuit diagram is based on v4.2. According to the pictures, the joystick connector was replaced by a dual USB, presumably for keyboard and joystick. An Ethernet connector was placed into the position of the PS2 connector. It was available for order with both black and white casing. The gomaDOS+ is the first version, that uses the Qmtech Spartan 6 FGPA card. It can be considered a clone of the +Uno v1 and was released in June 2020. [»] The machine is consists of two parts. The part made by Villena essentially includes the connectors, an ESP 8266 Wi-Fi module, and the FlashROM. The developer card contains an LX16 or LX25 FGPA with 1, 2, or 4 megabytes of SRAM. The two cards also match in color. It was available with black and white casings. The XC6SLX25 has slightly over 24,000 gates and 117K block RAM, as well as 28.5K distributed RAM. [»] ZXDOS+ is a variant of the previous clone that can be installed into an acrylic case and was released next month. [»] The aforementioned smoked acrylic microcomputer case is used for the +Uno v2. [»] This also consists of two components. One is the Uno+ motherboard, while the other is an I/O card, which includes the connectors and other accessories. On the back of this card, you can find the composite video and audio out ports, as well as the Superfo-ear, which were already present in the predecessor model. Additionally, there are new features such as the dual joystick port and VGA output. On the left side, there is a PS/2 mouse/keyboard port and a volume control, while the SD card slot and microUSB are located on the opposite side. With the latter, the machine can also be used as a USB keyboard. The add-on card also includes an ESP12F Wi-Fi module and a Dream MIDI chip.
Aitor Gómez García's developments The Sugarless is an adapter card, which allows the use of ZX-Uno 4.1/4.2 motherboards in ZX Spectrum 128K+2A/2B/3 cases. The main constructor and coordinator of the initiative is Aitor Gómez García (spark2k06) from Barakaldo. The development was announced in December 2017 on the ZX-Uno [»], as well as Va de Retro [»] forums. Its goal is to make the machines made under Alan Sugar's authority to be 128K/128K+2 compatible. The individual initiative turned into a community development. It can be installed into the 128K+2 cases after expanding the power supply input or with other methods, such as connecting the PS2 port with wires. It is also compatible with the gray +2 machines' 5/8 ribbon cable the black machines' 11/13 connector, only the firmware works with different configuration files. Of course, it is possible to use it with other ZX-Uno clones through connections and adapter cables, if physical possibilities are allowing it. In addition to the L-shaped PCB, an Arduino Mega 2560 Rev3 card is also required or an ATmega128 microcontroller needs to be soldered onto the board. This includes spark2k06's zxunops2 and joy2ps2 firmwares. The former converts the ZX Spectrum keyboard codes into ZX-Uno PS/2 compatible, while the latter converts it into an Atari standard joystick. An optional possibility is the TZXDunio cassette unit emulator. If possible, it is recommended to use at least version 1.4 of the TZX compatible SD card unit. This board also has both external and internal connectors. Physically, the mainboard and the companion card are connected together at the joystick port for the Uno. The PS2 port is located at the original power supply connector on the rear panel. On the expansion slot is the first the microUSB, responsible for power supply and programming of the ATMega/Arduino. This is followed by the upside-down Uno standard RGB pin header. The external microSD slot is also located here, and finally the TZXDunio external connector pins. Instead of the original RS232/Midi, there is the EAR; and the AUX port has been replaced with a VGA connector. The factory RGB Din has been replaced with a nine-pin mini-Din, which is a ZX-GO+ compatible RGB output. Therefore, ZX-GO+ (compatible) RGB/VGA cables can also be used. The TV RCA port has been replaced with the same type of connector for PAL composite output, and the Audio-out jack is located where the original TAPE/Sound was. On the left side, there are the two joystick ports. One is the output of the ZX-Uno joystick connector, and the other is connected to the ATMega/Ardunio. The combined reset/extra micro switch is also located here. Long press is the power on/off switch, and short is the reset. It is possible to turn off only the Uno, in that case, the machine can be used as a PS/2 keyboard through the Ardunio/ATmega, and the Uno can be reprogrammed without opening through the external microUSB port. As for internal connectors, next to the joystick, there is the ZX-Uno Ear, and then the pass-through connector for PS2. To the left of the joystick, there is the Uno RGB/Audio microJST connector. It can also be found in pin form, and the Uno's SD card can be also used in the same way. Between the PS/2 connectors, there is the connector of the ZX Spectrum cassette unit. Next to the Ardunio, there are slots for the Spectrum keyboard ribbon cable. The connectors required for programming the ATmega 128 are located directly next to the chip socket. The composite input is present as an RCA connector. The Issue 1 schematic was completed by February 2018. [»], [»] At the same time, the adaptation of the ZXUnoPS2 and Joy2PS2 projects for the companion board has began. The PCBs arrived the following month and the first board was completed within the same month: [»], [»] Two hardware bugs remained on the board. One of them is, that for the TZXDunio 1.3, the cables need to be connected in reverse. This problem does not occur from version 1.4 onwards. There is a patch PCB available for the older versions in through-hole and surface-mounted versions. Alternatively, it is possible to make a patch cable. The other bug is, that two pins required for programming the ATmega are not properly carried out, so they need to be routed from the Arduino pin row. The constructor has made both the hardware and firmware sources available on Github. [»] The corresponding TZXDunio project is also public. [»] The ZXUnCore and ZXUno4ALL are also spark2k06's projects. They are based on the ZXUncore card, which is essentially a stripped-down ZX-Uno. [»] The first prototypes of ZXUnCore were followed by the Issue 2A and 2B. Their main innovation is the option for a dual FlashROM selectable by a jumper or switch. The 2A was made with the standard ZX-Uno memory module connector. The 2B is a later version compatible with the ZXUno4ALL project. Here the connector depth was reduced to 2 millimeters. So its allow more space for horizontal installation. The final version, the April 2021 Issue 3, has one FlashROM chip soldered onto the PCB, with the other being removable. The 512K/2 megabyte memory also had to be placed on the PCB for the reasons told at ZX-Uno VGA 2M. The developer also redesigned the wiring of the connector row. The VGA DAC circuit was removed from the board and implemented on the companion card. RGB signals can be obtained from the 2x40 connector row. The first member of the ZXUno4ALL series is the ZXUnPicoITX from May. [»] It includes the constructor's MonochromeVGA add-on built-in. With its help, we can simulate the monoVGA screen in three shades. Later, Aitor wrote special XT, CPC and ZX cores for UnCore to enable software activation of the monoVGA mode. [»] Next to the VGA interface, there is the audio out jack. On the right is the combined PS/2 keyboard and mouse, as well as the joystick port. On the opposite side are the microUSB power and EAR input. Mass storage is a normal-sized SD card. The connectors also have internal pin versions on the board. ZxUnGo+ is the variant that can be installed in 16K/48K/48K+ cases from July. [»] Among the external connectors, the PS/2 port is the first. On the place of the edge connector is the miniUSB power input, the reset, the FlashROM selector and the SD card slot. This is followed by the audio output and EAR. VGA out closes the line, for which the machine housing must be cut. The Wifi and Midi accessories also can be connected to the board. Made on the basis of Graphics Gremlin FGPA-based CGA/Hercules card, the combined sound/CGA card, which was also named to Graphics Gremlin, was completed in August. [»] Regarding the picture, we get CGA TTL and CGA composite outputs, complemented with monochrome options. The sound can be OPL3 stereo or AC97/HD Audio - obviously when used as a separate sound card, not with the XT/CGA combo. A ZXUnSugarless 3D render was also made as a KiCAD project, but no photo can be found about it...[»]
The Spanish clone in Russia... The ZX-Uno 1010 from Evgenij Lozovoj (UzixLS, Eugene L) in Belgorod is a ZX-Uno VGA 2M (and thus 4.1) compatible version implemented on 10x10cm from September of 2021. [»] In terms of specifications, it differs in that it has a separate PS/2 mouse and keyboard connectors. Two pieces of W25Q128 FlashROM were also placed on the motherboard with a jumper selector. Loading programs here is also possible via Bluetooth. The Dream SAM 2695 Midi chip has also been integrated, just as the ESP-12F Wi-Fi module. In addition to the three buttons, the front panel also has the same number of indicator LEDs. The motherboard is optimized for G738 and G706 plastic instrument boxes. Based on the error list, rev.A1 was also completed by the end of the year. Like Lozovoy's other projects, it can be ordered as an empty PCB or ready-assembled from PCBWay. [»] Paul also sells it as an empty motherboard. [»]
... and in Ukraine. The ZX-Uno Pi edition includes integrated Wi-Fi and Midi expansions. The machine, which can be installed into Raspberry Pi 3B case, is based on the VGA 2M model. Its constructor, Sergej Belinski (tank-uk from Zaporizhia, Ukraine), introduced it on the zx.pk.ru forum in March 2021. [»] The RAM and FlashROM sizes are the same as in the case of the model it was based on. The VGA and microUSB power connectors are also present. Alexander Sharikhin (nihirash from Tbilisi-Georgia) also designed 3D printed cases for it in two versions. [»] The wireless Internet card is an ESP7 or ESP12 module, and the base of the Midi part is the Dream SAM 9773 chip. Joystick module(s) can be connected through a separate pin row. RC 2.0 implementation has been achieved and this version can also be ordered from Pavel. It already has a the connection possibility of double joysticks, unlike its predecessor, which has single port. [»] The original GitHub page has been deleted, but fortunately a mirrored version is available. [»]
↑date: 2023/08 |
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Ramon Martinez (rampa069) from Monovar presented the ZX-ESPectrum firmware-clone in April 2019. The ESP in the name refers to one of the components, the ESP32 minicard and perhaps to the Spanish origin. The mini developer card must be inserted into a Bitluni ESP32 VGA or a Lilygo TTGO VGA card to connect it to a VGA monitor. In the case of ESP32 cards without PSRAM, only ZX Spectrum 16/48K machines can be emulated, with those equipped with 4/8 megabytes of PSRAM, 128K/128K+2 and 128K+3 simulation is also possible. When loading, .TAP and .SNA files can be used, and it can save in .SNA format. Compatible with PS/2 keyboards. With further firmware updates, enhancing of functions can be expected. David Crespo Tascon (dcrespo3d), a freelance programmer from Madrid, was got know about the to ESP32-based development cards by one of his client. At the end of the project, he first bought the Espressif ESP32-WRover card for his own use. After some experimenting, he found Ramon Martinez's emulator and decided to fork it, adding support for the wireless Wii controller. Since this controller has seven buttons in addition to the D-pad, most games work perfectly with it. He was ready for July 2020 with its firmware emulator, the ZX-ESPectrum-Wiimote. In terms of implementation, a separate .TXT file for each game is responsible for pairing the keyboard and controller buttons. The hardware was eventually integrated into a Periboard 409 Mini keyboard in August, which also housed the VGA, 3.5 audio jack and USB-B power connectors. A Lilygo TTGo VGA32 card, also based on ESP32 but with its own PS/2 and VGA connectors, was purchased in September and used to continue emulator development. The colour depth of the VGA has been changed from 3 to 6 bits, so that the ZX Spectrum Bright attribute, missing from the previous emulator version, has been implemented. Also was fixed the bug of accessing the lower 16K memory segment in Rampa's emulator. The project was on hiatus until February 2021, when Lilygo received a 3D printed house. Then he implemented the support of 4:3 ratio monitors and a microSD slot. By March, he was unified the code for the standard ESP32 development cards and the Lilygo (99.9% identical), and added support for the .Z80 file format and AY-chip (partially). Unfortunately, it is the controller functionality, that we see the least on the videos... |
 ZX-ESPectrum on ESP32 with bitluni VGA2019/04.  Lilygo TTGo VGA322019/04.  ZX-ESPectrum-Wiimote on ESP322020/07.  ZX-ESPectrum-Wiimote on Lilygo TTGo VGA322020/10. |
| ZX128u+ |
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In June of 2020, the Spanish ZX128u+ clone was published on the va-de-retro.com forum. The motherboard is compatible with all Sinclair and Amstrad Spectrums, with the ULAplus display standard which is capable of displaying up to 260 colours, and uses an emulated DivMMC interface as mass storage. The board is designed by BCH from Barcelona, the firmware is done by Kyp [↓] in Madrid. Several other active hardware and software members of the forum also participated in the development. The original concept was to create a ZX Spectrum 128K+2A/+2B/+3/+3B compatible machine with ULAplus support, using emulated ZXMMC and DivMMC as storage media. As the list of machines was extended to include 48K(+)/128K/128K+2 Spectrums, ZXMMC support had to be dropped, as the interface is not compatible with them. The board, which can be built into 48K(+) cases, based on the Superfo’s Harlequin clone, contains a real Z80 processor and AY chip with 2x128K RAM. From this 2x64K is system memory and 2x64K is reserved for DivMMC. The 64 byte of ULAPlus palette is stored in a separate 32K RAM. The 512K ROM can contain a total of 8 sets of 64K ROMs, including esxDOS, the operating system of DivMMC, in addition to the Spectrum ROMs. The Xilinx XC95288XL CPLD is responsible for emulating the Kempston joystick and DivMMC card. The image is converted to RGB format by a 9-bit digital-to-analog converter. Here the signals are amplified for better image quality. On the quad board, of which test 05b is the final version, 90% of the components are representing the urface mount technology. Of course, the classic chips such as Z80 and AY are using hole mounting technology. |
 ZX128u+2020/06. |
| US-002. Alex Freed's clones |
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Alex Freed from San Francisco began development of his FGPA-based ZX clone in February 2006. This was his third machine based on Xilinx Spartan 3. He was started with the Russian Electronika BK0010, followed by the Apple II, and finally the ZX Spectrum 128K. [»] Later, after adding some expansion, he ported the Apple-Sinclair projects to the Altera DE-1 devboard. [»] So, he made the first clone on a Diligent Xilinx Spartan-3 card in February of 2006. Its central unit is a Xilinx Spartan 3 XC3S200 FGPA chip. Has 24K of internal RAM and, according to its name, it has 200,000 logic gates. The card containing the chip is characterized by 250K FlashROM and 1024K SRAM. VGA and RS-232 are on the left side of the card, and a single PS/2 port for the mouse and keyboard is on the right. Feedback is provided by four seven-segment LED displays and eight simple LED lights. The number of microswitches is also four and the number of two-position switches is again eight. He initially created a 48K Spectrum as he used the FGPA's internal RAM and could only fit a 16K ROM (he also used this method when emulating the Apple II). The processor is a TV80 softcore running at 28MHz. In principle, it would also run at 56MHz, but the author did not see any particular point using this super turbo. Later, the 128K Spectrum was realized, first without an AY chip, and then the latter was also implemented. He was made a mini-expansion card for the final configuration. This can be used to load .TAP files from a sound card, and presumably files from a real cassette too. The card also contains a 256K EEPROM, from which the emulator is loaded. Initially, he wanted to use an IDE-based CF card solution left from the Apple II project, but later decided to develop a target hardware. At the end of January of 2008, a version based on the Altera DE-1 was ported. [»] This is a 2in1 emulator: Apple and ZX in one, where you can select the start option from the menu. The novelty of the Spectrum part was the use of .TAP, .SNA and .SCR files from the MMC/SD card. [»] Later, he solved the problem of using ResiDOS on the machine. Since the devboard did not have battery-backed RAM, the operating system is loaded from the memory card, similar to a snapshot. The ready-made clone was published on 2008 October on his website. [»] ↑date: 2022/12 |
| Dmitrij Samsonov's clones |
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The originally Russian, at the moment living in Ma'alot-Tarshiha, Israel, Dmitry Samsonov (sdima1357) software engineer specialises in firmware ZX Spectrum clones on cheap development boards. These machines have modular design, so for the cards are attached the screens, microSD card slots and various USB devices. The Spectrum48 TV implements a black-and-white (more precisely: grayscale) ZX Spectrum on a STM32F401CCU6 Black Pill development board. The 20.8x52.8mm card, which can be found for $3, is based on a 32-bit ARM Cortex M4 processor running at up to 84MHz with 256K FlashROM and 64K RAM. The size of RAM and FlashROM already limits the knowledge of the firmware clone released in October 2020. Therefore, this 48K implementation can only display grayscale, and the type of handled file formats is also limited to the triad of .SNA, .Z80, and .TAP. The TV-out, audio output and SD card ports can be connected to the card's pin connectors, and the keyboard to the USB port. In April of 2021 he was published the release of his new clone, the ZX Spectrum 128K on ESP32 devboard. Accessories are connected to the development board via a breadboard. USB keyboard and mouse inputs, and analog 50Hz PAL TV output are provided on the firmware clone. The microSD card handles FAT32 partitions and the system supports 48K and 128K .TAP, .Z80 and .SNA files. Extra functions can be accessed by the F keys on the keyboard. |
 Spectrum48 TV2020.  ZX Spectrum 128K on ESP32 devboard2021/04. |
| Andrey Belykh's clones |
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One of the hobby projects of Toronto software engineer Andrey Belykh (abelykh0) is the ZX Spectrum Emulator on STM32F407. The firmware clone -as its name suggests- based on the STM32F407VET6 microcontroller from STMicroelectronics, which is hosted on an STM32 F4VE card. The 168MHz Cortex M4 processor integrated into the controller unit, along with 512K FlashROM and 192K SRAM, is not only responsible for Spectrum emulation, but also for the VGA driver and the microSD card's FatFs file system. The machine, with its minor and major bugs, reads and writes .Z80 files. Audio is exported through an USB-Midi cable. As a small attention, the OSD menu also displays the original ZX Spectrum keyboard layout. |
 ZX Spectrum Emulator on STM32F4072020/5. |
| Hermit Retro ZXZero |
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The aim of Alistair Carty, founder of Glasgow-based Hermit Retro Ltd, is to provide authentic ZX Spectrum retro computer experience using modern hardware and original Sinclair machine caes (or replicas). The Hermit Retro ZXZero emulator-clone, based on the Raspberry Pi Zero W(H), was launched in early April 2021. Development started under the name Unclear PX Spectrum, but the was changed to avoid potential legal problems. The kit can be installed into ZX Spectrum and ZX Spectrum+ cases without any changes. The hardware consists of four cards in addition to the Pi. The largest of course is the motherboard itself. The USB and joystick/HDMI modules are connected directly to it. Finally, the last mini card, the Pi Zero USB stem, connects the Pi to the motherboard - without the physical USB ports, using only the pins. As for external connections, the 5 volt jack, Atari joy, the aforementioned HDMI, microSD, I2C serial port (on stereo audio jack) and the also above-mentioned USB connectors are found on the back of the motherboard, along with an NMI button. The HDMI and USB connectors are full size for reliability. The joystick port also supports the two-button Arcade R joystick. A stripped-down Linux kernel and a modded Fuse emulator version consists the firmware, which boots in 2-3 seconds. The firmware is on the card in the Pi's own microSD slot, so it's inside the machine. The Fuse emulator has been modified to be ZXDB compatible, so you can load programs online. It also supports the Zelux illuminated keyboard and the Playstation 3 controller. The motherboard can be used with both the Raspberry Pi Zero W and the Raspberry Pi Zero WH (the two cards are identical in terms of capabilities, but the WH has an integrated pin row). The ZXZero is available as an ready-made, DIY- and blank PCB kit. It is also freely available to anyone as a Github project. |
 Hermit Retro ZXZero2021/04. |
| Didaktik M 48/128 and Kompakt 48/128/Professional |
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Didaktik Skalica company was founded in 1971 in Bratislava in the ex-Czechoslovakian Republic. Primary profile of company are school accessories, but they were tasting also into the computer industry. Their very first computers -Didaktik Alfa and Beta- weren't ZX Spectrum clones. In fact, the same happened as in most Central-Eastern European ex-socialist countries: at the company realised, can be a far better business to copy the ZX Spectrum with its thousand of games (or even it is reached ten thousand?) rather than developing completely new machines. In that way were born the Didaktik Gama 87, 88 and 89. By the way, these machines were quite popular in Poland too. The company - thanks to the still high PC prices in the former Czechoslovakia - launched his two last ZX Spectrum clones in early 1990s after Gamma series. These were Didaktik M and Kompakt. Parallel with the machines were released the D40 (5.25 inch/DD/360K) and D80 (3.5 inch/DD/720K) disk systems. In 1994, Didaktik Skalica moved to PCs, and sold the right of manufacturing and distributing to Kompakt Servis (Kompakt Services) in the Czech Republic, which was a single man enterprise and the machines were sold until 2008. The Didaktik M was appeared in two versions. Versions from 1990 and 1991 are differing primarily in the controlling system of the keyboard. The Didaktik M was made in higher quality as the Gama series with ergonomic casing and keyboard (with separate cursor buttons) and this was created them a more professional looking machine, than they in reality. The hardware was undergone an extensive redesign. The task of ULA was taken over by the Russian Angstrem T34B1 circuit and the ROM chip (T34RE1), which was also came from them. This system was actually the ancestor of today's chipsets. The RAM was used a single 64K chip of 48K, so there was no separate fast and slow memory. Thanks to all of these, theoretically it would be more compatible with Russian clones, yet it was able to achieve almost 100% ZX Spectrum compatibility. One of the two joy ports is Kempston and the other Sinclair compatible, but their "connectors" (which in reality the part of motherboard) is only compatible with the Didaktik joysticks. The cassette unit and power supply are both DIN standards. The picture output is TV or monochrome composite. There is also present a Sinclair compatible edge connector. Didaktik Kompakt from 1992 is a Didaktik M with built-in D80 drive. Another novelty is the RGB output via Scart socket, as well as a parallel bus and a system edge connector. The power supply was also installed in the computer’s case. The Snap button of D40 and D80 floppy drives can be accessed through the keyboard. Joystick connectors has returned to the Atari standard. The ROM used in these machines was reused in several ex-Soviet clones. Kompakt Services was made two big bros of these machines by using their motherboards. Didaktik Kompakt Professional is a machine built into a PC-case with two 5.25-inch drives controlled by the D40/D80; the Melodik, Kempston Mouse and PC keyboard interfaces were also integrated into the system. The Didaktik Kompakt 128 uses a Didaktik M motherboard expanded to 128K. The built-in D40/D80 interface here controls two 3.5-inch drives. The Melodik, Kempston Mouse and PC keyboard interfaces are present in the same way as in the case of previous one. Updated: 2018. October |
 Didaktik M 1990
 Didaktik Kompakt 1992
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| Didaktik Gama 192KB, Didaktik Gama 256KB Millennium Edition |
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Didaktik Gama 192K is the project of the Czech Petr Valecko (ie CSS Electronics) aimed to to build a 100% 128K compatible clone based on Didaktik Gama 89. This has succesfully achieved as the 'basic components' are the same: a Z80A processor at 3.5MHz and AY-3-8912 sound chip - the latter being tuned to ACB stereo in accordance with the former Czechoslovakian habit. In addition, standard RS-232C and parallel ports are also found on the motherboard. As can be seen, the size of RAM size was grew to 192K. ROMs are available from 32Kb EPROM 27256C. In addition, the snowing effect of ULA was also successfully avoided and the TV signal and tape input quality was improved too. The motherboard is designed in that way, that old parts can be refitted into it and the board can be easily installed into the original Gamma case. Of course, the motherboard itself also higher quality than the original. Interestingly, the video memory is placed on a separate card, and attached to the motherboard with a spacer. Designing was made from November 2003 to March 2004. Three subversions are exists: v1a (never was released), v1b and v1c. Petr was also offered a limited version, it was called Didaktik Gama 256KB Millennium Edition or Didaktik Gama 256KB Nemesis. As can be expected, the most important innovation here is, that the RAM was expanded to 256K. Updated: 2018. November |
 Didaktik 192KB v1c board
 Didaktik 192KB v1c assembled
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| ZX Spectrum +3s |
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The ZX Spectrum +3s is a real new development, which is created by the Romanian Cristian Secara (nick: Secarica). Letter 's' is pointing to his nickname. The project was begin in 1989, and some part of it did not finished yet. Purpose of Secarica was to make such machine, which is compatible with all Spectrums and capable of running CP/M. Well, the machine is 99% +3 compatible, and has various extras: 14MHz speed, 1024K RAM, 64K vRAM. With shadowing, any Spectrum ROMs can be loaded. Sound source is the AY-3-8910 chip, mass storage units are 2x1.44 megabyte floppies. Picture is sent to RGB, PAL and composite video output. Eight new function keys as well the conventional Kempston joystick port also get the place. The IN#FF video bug found in the original +3 was eliminated, so almost all 48/128K classic games are running fine. The mainboard was made in three different subversions: first was running at 3,5/7MHz, second is around 3,5/7/11MHz, and the latest is the present. In past times, contained an overlocked 10MHz CPU, nowadays it uses a downclocked 20 MHz one. Unfortunately, the current system will not allow higher speed than approximately 15,5 MHz. Due to lack of space, two smaller circuits (which were originally the part of the original mainboard design) were realised on separate two smaller boards. The floppy controller was taken from the Romanian Cobra clone, and the author had to made smaller modifications to work properly with 3,5 HD disks, not only with 5,25 and 8" ones. The PAL encoder card is an own design. Base resolution is the same of the original machines, but it is offers two another: the hi-res mode and the possibility of switching on and off the horizontal and/or the vertical border. In that case, picture is stretched to the whole screen. The author is still working about the display improvement of the CP/M mode as well on the final version of real time clock. Also a problem for the developer to find a suitable case for mounting respecting the size of mainboard. He is still working of connecting submodules, for example building the audio circuit. On his homepage, some +3 fixes also found, which were used during the development of superclone. The buggy AY sound was fixed along with a stereo tuning. Beeper was separated to the TV speaker, the sound of AY-chip is to two RCAs or sent to the RGB peritel port. In that way DIN cables can used. The already mentioned IN#FF video bug fixing is also on the homepage. He was tinkering composite video output for the +3 and +2A/B too. Basically, it is the circuit of the older 128K/128K+2 machines, which are left out from the last, cost efficient Spectrums. Some hints and tips also found about using and mounting internal 3,5" drives. 180, 720 and 800K disks are useable. Sadly, modern floppy drive units are not compatible, so must hunt for old XT or XT/AT types. |
 ZX Spectrum +3s 3rd revision
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| SpeccyBob |
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SpeccyBob name covers two clone prototypes. The normal version (SpeccyBob 2) is an extended clone with extra functions (which are not really extra in the 21. century...). In fact, they are the same as we can found at the modern Spectrums: new video modes, IDE interface, 4 megs of RAM etc. etc. SpeccyBob Lite is a simple ZX-clone built from contemporary electronics parts. It is only a 48K Spectrum clone, but compatibility at least is 99%. This is not even achieved by Amstrad in the old days... Of course, the second one is much closer to realisation, you could see photos from the working machine. SpeccyBob consists of three mainboards - so looking quite different from the original Spectrum. The homepage is not accessible for a long time. |
 SpeccyBob Lite
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| Chrome |
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Chrome is the "Italian clone", which was developed in 2004 on the basis of SpeccyBob Lite. Its constructor is Mario Prato, who a decade later created the DivMMC interface as well. Opposite of its forefather, not only compatible with standard 48K Spectrum, but as well with its 128K brother. It offers various extras, such as the 7MHz turbo mode realized with Z80C processor, and the further introduced +D floppy interface. By the author's opinion, compatibility reached 99,9%, although some demos do not work perfectly. Size of RAM is 160K, and sound is produced by the usual AY chip in stereo. It has Kempston compatible joystick port and a Centronics interface too. Beside the floppy disk, conventional tape cassettes can used as storage devices. Picture leaded out through a Scart connector. Additionally, a real time clock is also placed on the mainboard. The machine is consists of 12 chips, and looks very professionally. The developer put it into a self-made black aluminium case. Maciej Gruszecki, aka pear, was created the Chrome 128 motherboard within the frames of Speccy.pl virtual community. This one is based on the original clone and can be built into the housing of the original ZX Spectrum. The red colour board has three known editions: Issue 3, 3A and 3B. Updated: 2019.January |
 Chrome prototype v1
 Chrome prototype v2
 Chrome prototype v2 mod
 Chrome
 Chrome 128K Issue 3
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| ZX Badaloc |
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Alessandro Poppi’s ZX-Badaloc clone only one (perfectly working) CPLD-based wired prototype exists. Currently, onwards 2008, the project has been running on FGPA basis. Badaloc is "surprisingly fast" in Modena slang, referring to the machine up to 21MHz peak speed. Otherwise the frequency of clock can be varied between 3.5, 7, 14 and 21 MHz in multiple steps. Its basic components three Xilinx CPLDs: the XCR3384XL is the ULA emulator and has two XC9572XLs. One is charge for I/O operations, and the other for the keyboard (PS/2), Kempston compatible mouse (PS/2) and controlling the joystick along with a PIC16F877 microcontroller. A 20MHz Z84 processor controls the memory chips, the Flashable firmware EP(ROM), the AY-chip (stereofized) and the SD/MMC interface, together with a real-time clock, which one is a Dallas DS 1210/1307 type. By the way, the interface was implemented as a separate project known as ZXMMC card can be up to 32 characters length, the file system is not standardized. Not only ability to read from memory cards, but also from a host PC using UART. Keyboard controller is capable of handling the conventional 40 keys matrix, so the PS/2 keyboard is not necessary. In case of PC-keyboard, combined key functions are also available. The video circuit of course, was integrated into that CPLD, which emulates the ULA and it is VGA compatible. There are two modes: one is the standard Spectrum, another resolution is 320x256 with 16 colors. Size of RAM consists from the video memory of the scan-converter (128K) as well the ZX Spectrum memory (128-512K) and the video memory of Spectrum (32K dual-port). Into the ROM slot 27C512 - 27C4001 EPROM (64-512KByte) or FlashROM can be fitted, so 4-32 pieces 16K-ROMs can be stored at the same time. The machine itself able burning the FlashROM. Sinclair edge connector was managed to build almost to 100% compatibility. At least, the ZX Printer works with it. A ZX-Badaloc Reloaded is the continuation of previous project, integrated into FPGA circuits instead of CPLD basis. Hence from here comes the alternative, ZX-Badaloc FGPA name. With this solved the main problem, the cable jungle. Development immediately split into two ways. First was built around a Xilinx Spartan 3E HW-SPAR3E-SK-UNI-G card. Meanwhile, a small, low cost version, based on the Avnet Spartan 3A card was realized as the ZX-Badaloc Nano. The soul of this subversion is the 3A-400 FPGA. Since the card does not contain either VGA or PS/2 port, so they were implemented on a special mini card. The RS-232 port has been replaced by an USB one. As it does not have considerable RAM, so only able to emulate the 16K Spectrum. Finally, the two developments was combined onto a Digilent Nexys2 Spartan 3E card, using a XC3S1200E FGPA (it is possible, that Xilinx Spartan XCS500E also be able to manage the project). On the new card, some functions have not been implemented. They are on a separate board, on the Digilent's "pmod" module were realized, which is containing the cassette, speaker, joystick and SD card interface, as well as the Flash feature. This was drove the LEDs until it was replaced by the OSD. The card would otherwise be able to run the main functions of the clone itself. Has real MIC/EAR jacks and speaker outputs, which can serve the emulated AY-chip (YM2149 core by mikejd). Also though the RCA audio output can be heard both the beeper and the AY-chip. PS/2 keyboard can be also connected to it. It performs serial communication via RS-232 port. Programmable joystick port is provided too. The SD card reader was also remain on it. This clone is compatible with the ZX Spectrum 48/128/128K+2/128K+2A and +2B/128K+3 machines exception of emulation of lower 16K slow memory. Speed of the processor now also works on 28 and 42MHz with T80 core emulation (FPGA Arcade T80). 8 pieces of 512K RAM in it, for each part belongs the same amount of Flash memory. These are emulated by the RAM, so a wide range of ROMs can be handled by the SPI Flash. VGA now has 256 colors and the Spectrum mode supports the ULA+ based on Alessandro Dorigatti’s code. |
 ZX-Badaloc
 ZX-Badaloc Reloaded on Xilinx Spartan 3E
 ZX-Badaloc Nano
 ZX-Badaloc Reloaded on Digilent Nexys2 Spartan 3E
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| ZX Spectrum 2009 Remake |
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The ZX Spectrum 2009 Remake Remake is the clone of Gennaro Montedoro from the (very) first day of 2009. Its main features the low power consumption (360mA), the 100% Spectrum compatibility, and the easy building, which is partly due to the design, which counts 15 ICs less, than the original. This because the reduction of the number of memory and their controller chips. It is usable with the original Sinclair power supply. It contains a 'small' tuning facility. As is reality the two 16K DRAMs are 64K ones, so possible to transform to a 128K clone. Updated: 2012. March |
 ZX Spectrum 2009 Remake
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| ZX Spectrum 48K Issue 4V |
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Andrea Vavassori (aka Vava) from Bergamo, Northern Italy, was posted on the Italian Freelists.org forum in March 2019 his self-designed ZX Spectrum 48K Issue 4V motherboard for 16K/48K/48K+ chassis. His goal was to create a reliable, easy to service and bug-free board. The PCB is based on Issue 4B, firstly as the RAM control unit in this release is based on commercially available electronics without special components. On the other hand, it is considered by the experts to be the most reliable and easy to service 48K variant. The 'V' is the initial of the family name. Both sides of the motherboard were made with silkscreen technology (only one side on the original Spectrum) and the edge connector is gold-plated. Red, blue, yellow, white and black versions are also available for a small extra charge. The machine also has polarity protection, unlike the original Spectrum, and both UHF modulator and composite RCA can be used. The motherboard has improved interference filtering on the +12V line, that runs alongside the lower 16K RAM - which is very helpful for image quality. Jumpers on this model allow you to use not only NEC and Hitachi ROMs, but also custom 16/32K capacity EPROMs. One 'feature' of the Spectrums, the dot-crawl, can also be reduced with the potentiometer introduced in Issue2, or with a fixed resistor, that debuted in later versions. As the the most frequently failing lower 4116 chips of 16K RAM are now hard to come by, the 4164 and 41256/4256 types are also supported via a jumper line. The motherboard is also available with chip sockets, capacitor kits (compatible with both axial and radial types) and conversion kits. Latter ones are intended to be possible to use other issues as donors beside 4B. |
 ZX Spectrum 48K Issue 4V2019/03. |
| ESP8266 ZX Spectrum Emulator |
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The ESP8266 ZX Spectrum Emulator from November 2020 is aldolo's (aldolo69, aldo b) emulator clone from Italy. Its basic components are an ESP8266 microcontroller, a 2.4 inch ili9341 TFT LCD screen with SD card slot and Marat Fayzullin's emulator. It supports .Z80 files, which can be read from the EEPROM and SD card and also can written to the card. The joystick is emulated using MSX-style directional keys. In addition to the speaker, there are also buttons on the breadboard for controlling the emulator itself. |
 ESP8266 ZX Spectrum Emulator2020/11. |
| ZX Spectrum S2008 |
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In 2008 some Croatian ZX Spectrum fans were created the ZX Spectrum S2008: Tomislav Talan, Ivan Siric, Zoran Boskovic, Suad Cokljat, Vlado Banda and Kresimir Slonjsek. Initially, they wanted to make an additional module for the Spectrum with CF reader and joystick, but the result became a complete, upgraded ZX Spectrum 48K clone. The motherboard was used SMD technology with retaining some of the original components. For example the Z80 and the ULA. The original machine case has been modified according to the new connectors and the keypad foil is now has wired connection to the system board. The integrated ZXCF interface uses 1 megabyte of battery backed SRAM with the ResiDOS operating system. It has NMI and reset buttons. With the NMI, programs what copied into the RAM will be retained even after reset and shutdown thanks to the battery. The joystick interface is Kempston-compatible, the sound is made by an AY 8192 chip, taking out in stereo through a 3.5-pin jack - with adjustable balance, bass and treble. It also includes a so-called protoboard for future developments and additions. Has also a built-in RS232 interface and a composite out. You can choose from four ROM sets with DIP switches. The first 10 series was made of 5-5 red and green motherboards. The second series also including bug fixes. By the opinion of the main constructor, Zoran, it is possible to upgrade the machine to 128K with RGB output with the protoboard, but looks like the project has stopped for now. Added: 2018. September |
 ZX Spectrum S2008 mainboard
 ZX Spectrum S2008
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| Josip Perusanec's clones |
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Josip Perusanec’s (Deltasoft) hobby projects from Crotia are to implement 8-bit microcomputers and peripherals based on various microcontrollers. In addition to Sinclair-firmware clones on Microchip Technology and STMicroelectronics devices, there are also ex-Yugoslavian Galaksija, Galeb and Orao machines in his repertoire. In the case of Spectrum clones, the microcontrollers are connected to a self-designed PCB, which provides standard connections for power, SD card, RGB video out, speaker and PS/2 keyboard. So we're talking about clones, that combine surface mount and thru-hole technology. His first Spectrum implementation, the ZX Spectrum 16K on STM32F103C8T6 microcontroller. The involved STMicroelectronics card has a 32-bit Cortex-M3 processor clocked at maximum 72MHz, and 64K FlashROM and 20K SRAM. In June of 2020, the ZX Spectrum 48K on STM32F103RET6 microcontroller firmware clone was released. Here, the microcontroller already has 512K FlashROM and 64K SRAM with the same processor. |
 ZX16K on STM32f103c8t6202?.  ZX48K on STM32f103ret6202?. |
| ZX Spectrum SE (Chloe) |
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The ZX Spectrum SE (codename: Chloe) is a second generation Spectrum clone, which is the development of Andrew Owen (Cheveron/Cheveron Group and Jarek Adamski from 1999. Although only only prototype was made, numerous emulator simulating it. The SE combines the memory techniques of Times TS2068 and ZX Spectrum 128K and adding further 16K for it. So altogether has 272K RAM. After the modding of Jarek the ZX Spectrum 128K part uses 144K, while the rest 128K SRAM is controlled by the Timex. The standard ROM was replaced to a 64K EPROM. From this only utilizes the machine 32K. First one is the modified 128K editor. Second is the 48K Basic ROM with some TR-DOS add-on. Added a 8K serial EPROM to the AY-3-8912. Thank to it, Timex and Sinclair modes both supported. Output is switchable ABC/ACB stereo. The beeper sounds is coming from the internal loudspeaker, but muted when loading or saving. Picture is done by the TC 2048 SCLD circuit instead of the ULA, in which Jarek was bugfixed the snow effect. It has more screen modes. Beside the normal one, supports the 512x192 Hi-res, and the Hi-colour with 8x1 attribute cells. Possible to use the two ones together, for example the top half of the screen is Hi-colour, and the bottom is Hi-res. Can be handful with text adventures. Due to the 27K videoRAM, four normal or two Hi-res or Hi-colour screens can be handled. Available software is primarily emulators: Acorn BBC B (unfinished), Apple I, Commodore VIC-20, Compukit UK101, Galaksija, Jupiter Ace, Phillips Videopac G7000, Sinclair ZX80, ZX81, ZX Spectrum, ZX Spectrum 128K and Timex Computer TC2068 can be the machine. Also emulates the Interface 2 ROM cartridges and Mikro-Plus cartridges. Chloe 280SE is the series production ready version. The CPU is Z804C0020 at 3.5MHz or 21MHz, with 256K RAM and 32K videoRAM. In the 32K FlashROM the SE Basic IV is the default operating system. The sound is done by the YM219F of course in stereo. As an extra, supports the ULAplus mode beside the Hi-res and Hi-colour. Chloe 140SE is a simplified version. Can not able to emulate the Times 20xx machines, as this memory region is missing. Comparing to the previos clone, it has only 128K RAM. | |
| ZX128 |
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ZX128 is a Lithuanian development, which was built on the basis of Leningrad 1 clone. The computer consists of three main elements: the mainboard itself, the video controller and the General Sound card is also could be connected to it. The speed of processor is 3,5MHz, and the size of memory -as the name suggests- 128K. Above that, it contains 32K SRAM, which is responsible for holding different operating systems. In the 64K ROM placed the ZX128 Commander utility too. The developer was not spared with various outputs. So picture can lead out either by Super VHS or RCA ports. Stereo music made by the Yamaha 2147F chip is ported to two RCAs and a stereo jack. The mainboard was also equipped with Kempston, Sinclair 1 and 2 compatible joystick ports. The real innovation is presenting of USB port. With this, we can use Flash cards as storage devices. Unfortunately no more news since August of 2007. Updated: 2019. March |
 ZX128
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| ZXGate |
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ZXGate project was started on the basis of Bodo Wenzels' ZX97 machine, which is a ZX81 clone. But in this case, the whole ZX81 is integrated into a single FGPA chip. Beside this, it contains three another classic computers as Jupiter Ace, TRS-80 as well ZX Spectrum. The ZX Spectrum ROM did not get place in the machine, must be loaded separately into the 32K SRAM. All of 48K functions are integrated into the machine. Of course, the author cannot promise 100% compatibility, because impossible to test it with all programmes. The machine has output for monochrome and colour monitors as well has a Super VHS port. | |||
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| ZX Coffee Classic |
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Coffee Coffee was released his second clone, the ZX Coffee Classic from Odintsovo, Russia in August of 2020. The first one was made in Moscow back in 1986. They are common in that, both copies the ROM content to RAM during booting. But why is the name Classic? Primarily because it is built from classic components and can be used with classic TV. The pocket-sized (10x9 cm) ZX Spectrum 48K/128K clone's Z84C0010 10MHz CMOS processor is ticking at 3.5 or 7MHz, the 14MHz overclocked version is still being tested. The AY-chip is also not emulated, the classic AY-3-8912 provides the music on a stereo jack or mono RCA connectors. You can also use an original cassette recorder through this jack. The size of the SRAM is 256K. In addition to the 128K ZX Spectrum RAM, the factory ROM set stored in FlashROM is also copied here , as mentioned in the introduction. FlashROM of 32 megabytes is justified by higher reliability than the SD card: a rewriting cycle above 100,000 with a data storage life of 20 years. The image can be displayed via the built-in 2.8-inch 320x240 LCD, PAL composite TV output, or S-Video output for better image quality. It is possible to use both the built-in and external screens at the same time. The 256x192 pixel resolution is used as an OSD. Other main components of the peripheral control Microchip PIC18F25K22 microcontroller and firmware requested are responsible altera altera MAX II EPM570T100C3 CPLD. In addition to the built-in Spectrum-compatible microwave switches, you can use the original ZX Spectrum foil membrane or PS/2 keyboard. If you don't stick to the built-in keyboard, you can reduce the vertical size of the motherboard by up to 3 cm. You can also leave the LCD screen. A standard 5-volt microUSB connector is responsible for powering the machine. So with the help of a powerbank it can even be portable, since its consumption is only around 170 mA. This is due, among other things, to the CMOS-based processor and the fact that only the AY-chip and PAL coder go on 5 volts, while the other units use only 3.3 volt voltage – using relatively powerful undervolting. The USB connector also provides connectivity to your PC. The reset button is located above the screen. For now, the . SNA and . TAP files are supported, but the . TRD is also planned. It includes a built-in browser for convenient program selection and a cassette magnetophone emulator for the . TAP files at normal and double speeds. The project is in continuous development, for example, hdmi, joypad expansion has also been solved - hopefully we can meet them in the successor model Espresso. |
 ZX Coffee Classic2020/8. |
| ZX Spectrum 48K on STM32F407 devboard |
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In March of 2019, Samuraj announced a new ZX Spectrum 48K firmware-clone, the ZX Spectrum 48K on STM32F407 devboard from Szczecin, Poland on the elektroda.pl forum. The STM32F407 development board from STMicroelectronics uses a 168 MHz, 32-bit Arm Cortex-M4 processor, with 512/1024K FlashROM and 192K SRAM for emulation. It is connected to a 16-key keyboard and a 3.2-inch TFT LCD. The .Z80 files can be read from a microSD card. |
 ZX Spectrum 48K on STM32F407 devboard2019/03. |
| ESPlay Micro |
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Fuji Pebri's (pebri86; Karawang-Indonesia) project is the ESPlay Micro handheld from November of 2019 . Inspired by the Odroid Go and Pocketsprite pocket consoles, the device emulates the ZX Spectrum in addition to classic consoles. The handheld is based on an ESP32 WROVER dual-core processor running at 80/160/240 MHz, with integrated 4MB Flash, 4MB PSRAM, Wi-Fi and Bluetooth. The screen is a 2.4-inch ILI9341 TFT Panel and data storage is provided by a microSD card. The sound of the UDA1334A based I2S DAC can be output via a 3.5mm jack, even can be used as an MP3 player. For developers, it also has a CH340C based USB to serial converter and a direct I2C serial port. Makerflabs, the firm which has been proposed to mass-produce the original, was developed a v2 version with its own acrylic case for November 2020. It also houses a battery and a built-in speaker. A 2.54" I2C breakout module is installed for developers. The processor here is a version with 16 megabytes of Flash and 8MB of PSRAM memory. |
 ESPlay Micro v12019/11.  ESPlay Micro v22020/11. |
| Eugene Yevhen Andruszczenko's clones |
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The Retro ESP32 firmware is the joint development of Eugene Yevhen Andruszczenko (32teeth-Toronto/Canada) and Fuji Pebri (pebri86-Karawang/Indonesia) for the ESP32 based ODROID-GO handheld. As the console is now a discontinued product, Eugene has created his own handheld console for the firmware, simply calling it Retro ESP32. This console, which can be mounted into a Gameboy Pocket case, currently emulates a dozen 8-bit consoles and microcomputers, including the ZX Spectrum 48K. It's available in two different forms from the author's Tindie store, the Handheld Gaming. Those who opt for the complete, assembled version, will also receive the SD-card with the firmware and a lithium-polymer battery in addition to the replica case. The battery must be installed into the cartridge case. |
 Retro ESP322020/02.  Retro ESP322020/02. |
| ZX Fuse Emulator on Bittboy Pocket-go |
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Thanks to Salvador Camacho Soto (aka Salvacam), the Bittboy Pocketgo, Miyoo, Powkiddy V90, Powkiddy Q90 handhelds can be used as ZX Spectrum since November 2020. The webmaster, who lives in Granada, Spain, has ported the Fuse emulator to this console-family, which now can be regarded as a successor to Vega+. Addition to this, several other 8-bit and 16-bit microcomputers and game console emulators have been added to these handhelds by the creator. |
 ZX Fuse Emulator on Bittboy Pocket-go2020/11. |
| SiDi FGPA |
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The SiDi FGPA card was developed by Manuel Fernandez Higueras (ManuFerHi - Terrassa, Spain) in 2019 based on the MIST FGPA card. Some features are missing, but the price is a fraction of the original. Similar to the MIST, among the various 8 and 16-bit micros, consoles and arcade machines the ZX Spectrum and its clones are emulated with the cores loaded from SD card to FGPA. The system is built around the Altera Cyclone IV EP4CE22 FPGA and 32 megabytes of RAM, the peripherals controlled by the ARM AT91SAM7S56 I/O controller. Two of the four USB ports are on the front panel, along with three LEDs, a reset button and a microSD slot. The remaining two are on the right side, along with the audio input jack. Of course, the power connector along with the power switch is on the back. In addition to this, the system can also be operated with microUSB power, which port can also be used to flash the I/O controller. Audio is provided via a 3.5mm stereo jack, while the video signal output is sent through by analogue VGA and RGB connectors. For developers, the FGPA can be directly connected by the JTAG and serial ports, the latter also allowing limited expansion of the card. It can be ordered as a bare motherboard, as well as in a transparent acrylic or painted metal case. In the case of metal housing, we unfortunately have to give up the visibility of the LEDs integrated onto the motherboard. |
 SiDi FGPA2019. |
| Antonio Villena's clones |
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Antonio Villena's nepUNO FGPA-based retro computer clone was released in October of 2020. The console, based on the Cyclone IV board, contains an EP4CE55F23 FGPA. It has 55,000 cells, 32 megabytes of SDRAM and 2 megabytes of SRAM, along with 8 megabytes of FlashROM. This is between the MiST and MiSTer FGPA emulators in terms of performance. It has dual joystick and PS/2 ports, audio I/O, microSD, USB and VGA connectors. Wi-fi is based on ESP8266. The edge connector is compatible with those on gomaDOS+ and ZXDOS+ clones. Of course, it can emulate the most popular 8-bit microcomputers (ZX48/128/Next, C16/64) without any problems with the performance already mentioned. |
 neptUNO2020/10. |
| Pocket ZX |
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The inhabitant of Cornwall (UK), stuartm2 has created the Pocket ZX handheld in April of 2019 as a participiant of the instructables.com website's Pocket sized competition, paying tribute to his first computer, the ZX Spectrum 48K. Based on the Raspberry Pi, the hardware development aims to be cheap, portable and to be have a keyboard and joystick. The latter two are controlled by an Ardunio Pro Micro. The screen is a Waveshare 3.2 inch 320x240 pixel touchscreen TFT LCD model. The HC-05 serial Bluetooth module provides wireless access, which can be omitted if the Raspberry Pi W is the central unit. A separate module controls the charging of the 2000 mAh 25C 1S LiPo battery and powers the system. The operating system is the Raspberry Pi OS (aka Raspbian) with the LCD drivers and Fuse emulator. |
 Pocket ZX2019/04. |
| Pocket ZX on STM32F103RET6 microcontroller |
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In March 2021, zelalex from Dnipropetrovsk announced his Pocket ZX on STM32F103RET6 microcontroller clone. The controller has a 32-bit 72MHz RISC ARM Cortex M3 processor, 512K FlashROM and 64K RAM. So, of course it can only emulate the 48K Spectrum. The screen is a 3.5 inch LQ035NC111 LCD panel with 320x240 resolution. With a microSD card, .Z80 files can be used. Controlling devices including a 40-button mini-keyboard and brightness/volume knobs. The 90x125 mm motherboard fits into a 95x130x16.5 mm two-piece 3D printed case, which also houses an 800mAh battery for portability. |
 Pocket ZX on STM32F103RET62021/03. |
| Pocket ZX Spectrum on Wemos D1 Mini devboard |
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Denes Nagymathe, currently living in London, announced his own handheld clone, the Pocket ZX Spectrum on Wemos D1 Mini devboard in October of 2020. The ZX Spectrum 48K clone was inspired by the project of aldolo, but this time the computer got a 3D printed case. On the hardware side, of course, the Wemos D1 Mini developer card is the basis of the machine, with its attached battery and charging controller. All 40 original ZX Spectrum buttons are included, plus two fire buttons for the mini Kempston joystick and one for the menu. The ILI9341 320x256 TFT display either can be 2.8 or 3.2 inches diameter. Programs can be stored on microSD card. The volume of the built-in speaker is adjustable and can be outputted via a jack. Software-wise is based on Marat Fayzullin's Z80 emulator, Bill Greiman's SDFat and Bodmer's TFT_eSPI libraries. |
 Pocket ZX on Wemos D1 Mini2020/10. |
| Keyboard-PI emulator-clones |
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Vilros LLC, based in Lakewood, USA, has come up with an interesting solution for retro machine enthusiasts. Released in June 2020, their wireless PC keyboard and touchpad combo offers the option to integrate a Raspberry Pi into it. This makes possible to emulate classic micro machines like the ZX Spectrum - all integrated into a single box. Plus, the classic 8-bit era keyboard offers enough space inside to do most of the moddings. |
 Vilros keyboard with hub for Raspberry PI2020/05. |
| Speccy 20xx |
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Speccy 2007 was originally a 48K clone built around the Altera EPM7128SLC84-15 programmable logic circuit and the ATMega16 controller. Thus, the cost of producing the complete motherboard could remain below $50. Unfortunately - as we used to say - the compatibility of the machine is far from the perfect. By the oppinion of Peter Kitsun (also known as Syd), who lives in Kiev, not necessary to build another ZX power plant, for that, there is for example the Pentagon 1024SL. His aim was to create a basic, original Spectrum with the help of today's available parts. You can connect PS/2 keyboard to the machine. The picture outputted to monitor and sound via RCA connector. The first version of the machine (Speccy 2007 v1.00) was released in December of 2007. With this machine the .TAP, .TZX and .SNA files downloaded from the Internet, can be load from an SD card up to four times faster. Nevertheless, thanks to press of the zx.pk.ru forum, Syd was improved the machine together with the members of the community. Speccy 2007 v1.04 came out in March 2008, which already had TR-DOS support. The next stage of development is associated with molodcov_alex (Aleksandr Molodcov). According to his plans, Speccy2007 v2.00 (Speccy2009) would work with the Z80 and 128K (Pentagon compatible) RAM built around the Altera EPM3256. The ATMega64 controller would be responsible for VG93 emulation and controlling of keyboard and mouse. The pictue would be scaled up to VGA output. Kempston joy connector and ZX Bus were also designed on the motherboard. Based on this idea, in April 2009, the 2007 v1.06 was released. This machine was already worked in the 128K+AY+TR-DOS setup, according to the above concepts. The controller finally became ATMega32, its capacity proved to be enough for 128K emulation, but the AY part was still on a separate card. Can already handle SD cards with larger capacity than 2 GB. This was further upgraded from St. Petersburg in May 2010. Ljubitel’s Speccy 2007 v1.1 has already integrated the AY/YM chip onto the motherboard. In the zx.pk.ru forum, in March of 2010 Elker was announced the revision 0 of the Speccy 2007+128K+AY motherboard, which had already contained the integrated PAL encoder circuit and the sound was also taken out by two RCAs. This was followed in the same month (?) by the Speccy 2007+128K+AY rev. 2010, with a professional PCB. According to the inscription on the motherboard, the exact name of machine is Speccy 2007/2-128 v1.0. In February 2012, Speccy2007+128K+AY rev.2012, .ie Speccy 2007/2-128 v1.2, was released with a firmware update. After a long break, on April 1 of 2016, .jackson was announced the Speccy 2007 128K+AY+TR-DOS (Speccy 2007 128K CMF) combo. Here, the single RAM memory was made by using of an old machine’s cache memory chip (the original design contains two chips). Its last firmware version is 1.06. The Speccy 2010 is a clone created by using the Altera Cyclone II FPGA (EP2C8Q208C8N) and the STMicroelectronics ARM7 (STR750FV2T6 or STR750FV2T6) CPU. It was inherited the the dimensions and main features of the Speccy 2007. Virtually we can create a variety of configurations, as standard, ZX Spectrum 48/128K and Pentagon 128/1024K modes are selectable. There is an SD/MMC card slot on it. The real-time clock type is Dallas DS1338Z-33 +, in this case emulates the Gluk RTC. There are two PS/2 ports (keyboard and mouse), 2 joy connectors and an optional USB. The mouse is Kempston compatible, and the joystick can be various standard. In case of video outputs, we can choose among RGB, Composite, S-Video or VGA images created by 3 R-2R DA converters. Audio production is the task of a TDA1543 or double R-2R. The (stereo) AY/YM modes, the TurboSound and of course the Beeper are supported. Despite being perfectly compatible with Speccy2007 v1.06, it also has several new features. For example, 1 megabytes of available memory (Pentagon 1024K emulation). Turbo speed can also be adjusted in several steps: 7, 14 or 28 MHz. Among the members of zx.pk.ru forum, Sabirzhanov Vadim Mirzhanovich (zst) undertook the task of "mass production" of Speccy 20xx series. Speccy 2007 had the ZXkit-002 name, the 2010 version has been released as a ZXkit-005 in his webshop. A ZXkit-004 was also available, it is an 128K Expander and integrated AY circuit for Speccy 2007. With this expansion, can be achieved the memory upgrade and stereo 3-channel music. Despite of its name, it uses the YM chip. The new webshop is offering only Speccy 2010. Updated: 2018. September |
 Speccy 2007 v1.00
 Speccy 2007 v1.06
 Speccy 2007 v1.1
 Speccy 2007+128K+AY rev.0
 Speccy 2007/2-128
 Speccy 2007+128K+AY+TR-DOS
 Speccy 2010 rev 2
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ReSpecT 48K, ReSpecT-2 (128K). |
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ReSpecT clone will made on the basis of SpeccyBob project. As its forebear, it has got two variants: ReSpecT 48K and ReSpecT-2 (128K). These clones are the prototypes of Z.A.N. from Russia. First version simulates a basic 48K Spectrum with again a help of Altera EPM7128SLC84-15 circuit. Second one offers numerous innovations such as new graphics modes: 256x224, 256x256 and 320x200 with 16 colours. Upcoming novelty in Spectrum terms the 4096 colours palette. From that, we can display 16 colours at the same time on the screen. So it is possible to realise more natural pictures. Beside this, the already mentioned Pentagon 1024SL v2.x's colour -per-pixel mode will also supported. In addition, author is planning to produce the 21 MHz high-speed version. |
Neo |
Dmitriy Schapotschkin (ILoveSpeccy)'s project is the Neo, which is based on a Xilinx Spartan XC3S400 programmable logical circuit and an ATMega 644 microcontroller. Equipped also with 3 pieces of 512K SRAM module and a SD-card slot. Its most interesting special feature, that all units of mainboard can be reprogrammed without opening the housing via the USB port. This ensuring limitless possibilities for developing of different configurations. The following peripherals are supported: VGA output with color-per-pixel ad 4096 colour mode, PS2 mouse and keyboard ports, stereo jack, tape, RS-232C and joystick ports. The PCB is one-sided, prepared at home by the author, therefore the computer can be easily repeated. |
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| FPGA Speccy |
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Alex Freed's FPGA Speccy project was released after the author's Apple II and Elektronika BK0010 (a Russian clone) machines. After successfully making two relatively rare retro replica clone around the Xilinx Spartan3 circuit, the time has come to create a new ZX Spectrum. The machine is still under development, and not only able to run at 3,5MHz, but has a turbo mode also with 28MHz at the moment, but by the testing programs it will run at 56MHz. So welcome a new speed champion among the ZX clones! Video output of the newcomer is VGA, because it has much more nice screen comparing to an ordinary TV set. Next stair of development is an IDE interface, in order to read the programs from CF cards. At the moment, .TAP files are loaded from sound card, which is good, but damn slooow. A 256K EEPROM contains the ROM routines of the 128K Spectrum, which loads into the internal memory (BRAM) of the FPGA at the booting process. |
 FPGA Speccy
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Ant-1024HD |
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The under development Ant-1024HD clone based on KAY 1024 as it was denoted before. Like another Russian clones, it also uses the Altera EPM7128SLC84-15 circuit. The clone contains Kempston joystick, keyboard, monitor printer and magnetofon ports. From the HD name seems, that hard disk can also connected to the machine, so on mainboard you can find an IDE controller. This can control the CD-ROM as well. The VHS cassette sized mainboard will be compatible with DMA Utra Sound Card. Certainly has 1024K RAM and supports the 7 MHz turbo mode. |
| Pentevo, Pentevo Light (Pentagon Evolution, ZX Evo, ZX Evolution) |
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Updated: 2018. May
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 Pentevo rev A
 Pentevo rev B
 Pentevo rev C
 Pentevo Light
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| ZXM-777 |
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The ZXM-777 is connected to Mick (Mikhail Tarasov) The machine was built in the spirit of ZX-777 and KAY-256, of which machines centre was the ATF16V8PAL circuit. Its innovation was the usage of SRAM modules, so can be born the first own-developed machine of Mick (revision 01). The turbo mode f machine is 7 MHZ, but not only the CPU, but the memory is also accelerated (by the way, it is the 'fast' cache memory of 386/486 era). The mainboard is AT standard. Between 2006 and 2008 two boards were made from revision 01. This was followed by the revision 02 with some minor modifications. The project was cancelled, as Mick gained the necessary practice for further developments.
Added: 2010. december 12. |
 ZXM-777 rev 01
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| ZXM-Phoenix, ZXM-Phoenix 2 |
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The ZXM-Phoenix clone is the development of Mick (Mikhail Tarasov). The idea of realization was appeared in the end of 2008 on the zx.pk.ru forum. The inspiration was based on, that members desired to wanted to remind to their youth. On the another hand, Mick liked to trying out himself in a whole project development. Development was begin in late 2008, with revision 00. Unfortunately users discovered a bug on the green mainboard, from which 6 pieces were made. By the way, it was targeted to realize without FGPA to bring the look and feel of 90's. The board which contains 71 chips, is controlled by the ATMega 8515 microcontroller. Also integrated on the board Caro's ZX Multi Card controller. The bugfixed first revision (01) was appeared in May 2009. and made 65 pieces of them again in green. In 2010, due to the request of members, Andrew Charles (CodeMaster) was produced a new series of 15 boards in China, with blue PCB in that case (revision 02). In the next year, from the 03 revision mainboard again produced 31 pieces and again in China. The development was co-ordinated by Anatoly Gajvoronsky (Zorel). The new mainboard was integrated the SD-Card controller, the new development of Vitaly Rudegenko (Keeper). Number of chips were raised to 72. Manufacturing was arranged by Dmitry Demyanekenko (ZEK). This board is red colour. As most fans also wanted a turbo mode, Mick fulfilled their desire. It was created on the base of the turbo mode of ZXM-777. In that way, was born the black coloured 04 revision number mainboard with 74 chips. Location of manufacturing again China, and the number of plates is 16. In 2012 was constructed the final edition, the revision number 05. In it was realized the 128K lock-up mode, which prevented the problem, when using some 128K only software. With the ATiny 13 micro-controller the power management also solved (the 12, 15 and 45 types also can be used). The number of chips again reduced to 72. The 15 pieces of mainboard set was again made in China. In the same year, after some bugfixes Zorel was decided another to made another 17 pieces. The board got the 05.1 revision number. The colour went to red again, and again was manufactured in China. The making of the last 21 pieces was done by Vitaly Mikhalkov (MV1971) from 2013. Worth to note, that in late 2012 released revision 06. But it not became 'official', as it not compatible with the others. Its case, that Mick tried to made Pentagon compatible the video timing. So the last official version is 05.2, not the yellow sixth, which was made in 15 pieces. The ZXM-Phoenix 2 clone was born from the modernization of its predecessor from 2010. It was crammed into CPLDs the most important functions (EPM7032 and EPM7064) Memory expanded to 4096KB with SIMM72 modules. This machine is not only KAY and Scorpion compatible, but also has Pentagon mode. Some new graphics modes also were introduced. For example the 15 or 16 colours already well-known modes and GigaScreen. The most important is the 15 or 16 colours from 128 colours palette and the 15 or 16 colours Border modes. The 7MHZ turbo mode is standard (memory runs constantly in turbo mode) just like the VGA output. In the development, more great Spectrum enthusiast took part also. Kamil Karimov (Caro)was helped to integrate the previously mentioned controller card. Tkacuku Valeriju (Black_Cat) was give help to create the audio mixer. Eugene Ivanov (Ewgeny7) take advices how to handle the extended memory. Rudenkomu Vitaly (Keeper) was provided a modificated floppy controller design and a lot of firmwares. Gerasimchuk Sergei (Zloy) took part in the implementation of the Scart interface. Stanislav Yudin (CityAceE) collected the old and new Spectrum fans on the forum. Andrew Shapovalov (Xobbiman) hosted the webspace for the project, until Mick does not made his own webpage. Dmitry Demyanenko (ZEK) designed the circuit of SD card controller.
Updated: 2015. December |
 ZXM-Phoenix revision 00
 ZXM-Phoenix revision 01
 ZXM-Phoenix revision 02
 ZXM-Phoenix revision 03
 ZXM-Phoenix revision 04
 ZXM-Phoenix revision 05
 ZXM-Phoenix revision 05.1
 ZXM-Phoenix revision 06
 ZXM-Phoenix 2
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| ZXM-Zephyr |
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Development of the ZXM-Zephyr was begin in the end of 2013, as the carrying-on of ZXM-Phoenix. project. While the phoenix recalled the retro age with its circuits, Mick was built the zephyr around the modern FGPA-basics. But in some aspects it is also retro, because the FLEX 8000 which was belongs to the Altera EPF88220A family, not manufactured already, so remained stocks was used. Creating the clone has two main reasons. First is to implement the ZXM-Phoenix into an FGPA in VHDL language. Second in to integrate the SAA1099 chip into a mainboard. So with the YM-chip altogether, the music is 9 channels. The memory of the machine is 512 or 1024K with two static RAM modules. The ROM is the 512K AM29F040 FlashROM. There is an IDE interface and Caro's ZX Multi Card interface was integrated, which is also the part of the phoenix. Of course, it has USB interface. As the machine is totally freely configurable except from a few parts, it is more like a development board, than a dedicated computer. But Mick was 'developed' a ZX Spectrum clone from it. Altogether 15 pieces were made from the revision 00 and 01 boards.
Added: 2014. December 07.
|  ZXM-Zephyr rev 00
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Pentagon 48K
Pentagon 48K Z01.90 mod
Pentagon 128K 2+ ATM
Pentagon 128K 2+ Z1992mod ATM
Pentagon 128K 3+ ATM
Pentagon 128K 3+ Solon
Pentagon 128K 4+ Solon
Pentagon 128K 3+ GRM
Pentagon 128K 4+ GRM v5
Pentagon 1024SL v1.0
Pentagon 1024SL v1.4
Pentagon 1024SL v1.41
Pentagon 1024SL v2.2
Z-Controller
Pentagon 1024SL v2.666
Pentagon 1024SL v2.666LE
ZX Evolution rev.A
ZX Evolution rev.B
ZX Evolution rev.C
Pentevo Light
ZX-Evo Video-DAC
ZX-Evo Video-DAC2
ZiFi board
ZiFi board+Joystick rev.C
Pentagon 48K mod.2008 King of Evil
Pentagon 128K mod.2011 Zorel
Pentagon 128K mod.2013 Zorel
Pentagon 128K mod.2014 Mick solegstar
Pentagon 128K mod.2015 Mick
Expansion board for Pentagon 128K
ZX4MB
Pentagon 512kB interface
Profi interface
Profi interface v3
ZX Nucleon 512KB v1b
ZX Nucleon 512KB v2a
!!!!ZX Nucleon 512KB v3b!!!!!!!
Profi v3.2 by Profi PLL
Profi v4.00
Profi v5.02
Profi v5.03
Profi v5.04 mod.2008 Savelij
Profi v5.05 mod.2012 solegstar
Profi v5.06 mod.2014 solegstar
Profi v6.2 revB mod.2010 Mdesk
Karabas Pro Rev.C
1 Mb SIMM30 module and CP/M color mod
Profi ZX Bus expander
Profi extender
Scorpion ZS 256 SC11
Scorpion ZS 256 SC14
Scorpion ZS 256 SC14 pirate
Scorpion ZS 256 SC15 pirate
Scorpion ZS 256 SC14 Turbo v1
Scorpion ZS 256 SC14 Turbo v2
Scorpion ZS 256 SC16 Turbo+
Scorpion ZS 256 Turbo+ mod.2007 Mikka_A
Scorpion ZS 256 Turbo+ Restored
Scorpion ZS 1024 Turbo+
Pentagon 128K 2+ timing mod
ATM Turbo 1 v4.10
ATM Turbo 1 v4.50
ATM Turbo 1 v5.20
ATM Turbo 2 v7.10 green
ATM Turbo 2++ v7.18
Connection boards
ATM Turbo 3 v8.00
ATM Turbo 2+ v7.11 mod.2020 paul
ATM Turbo 2++ tetroid v7.18
KAY 128
KAY 128 1SL
KAY 256 Turbo 3SL
KAY 1024 Turbo 3SL
KAY 1024 Turbo 3SL mod.2010 lyaMIV
KAY 1024 Turbo 3SL mod.2017 Pavel
KAY 1024 Turbo 3SL mod.2017 tigr101274
KAY 1024 Turbo 4SL mod.2010 Alex NEMO
KAY 1024 Turbo 4SL mod.2017 Paul
KAY 1024 Turbo 4SL mod.2018 Paul
AVR ZX Spectrum v1.0 microSD
AVR ZX Spectrum v2.0
AVR ZX Spectrum v2.0 mod.2017 Paul
AVR ZX Spectrum v2.1
AVR ZX Spectrum v2.2
Sizif-128 rev.0
Sizif-128 rev.A
Sizif-128 rev.B
Sizif-128 rev.C
Sizif-512 rev.A
Sizif-512 rev.C
Sizif-512 rev.C1
Sizif-512 rev.D
Sizif-512 rev.D1
Sizif-512 rev.E
Sizif-512 rev.E1
Sizif-512 extension rev.A1
Sizif-512 Wifi rev.C
Sizif-XXS rev.A
Sizif-XXS rev.B
Sizif-XXS Zero rev.A
Sizif-XXS Zero rev.A
ZX Coffee Classic
ZX Spectrum 128K+++
Speccy 2007 v1.03
Speccy 2007 v1.04
Speccy 2007 v1.03 128k mod
Speccy 2007 v1.06
Speccy 2007 128
Speccy 2007 128 mod.2016 .jacksn
Speccy 2007 128 mod.2017 paul white
Speccy 2007 128 mod.2017 paul green
Speccy 2010 rev.1
Speccy 2010 rev.2
ReVerSE-U10
ReVerSE-U9
ReVerSE-U8
ReVerSE-U16 rev.A
ReVerSE-U16 rev.C
DivGMX
Karabas-128 rev.A
Karabas-128 rev.A2
Karabas-128 rev.B1
Karabas Nano rev.C
Karabas Nano rev.G
Pocket ZX on one chip
Pentagon 512 on Altera DE1
ZX128
C4 Speccy 48K
Aeon v1.0
Aeon v2.0
Aeon Lite
Aeon
AX82
ZX Spectrum 48K on STM32F429I
Steccy
TensyCEC
espMCUME
Tensy4.0MCUME
T-Computer rev 3
PICOmputer
PICOmputer MAX
PICOmputer BOX
PICOmputer ZX
PICOmputer V
PICOmputer 28
retroVGA v1
PICOmputer gamer's edition
PICOZX
PICOmputer TOUCH
PICOZX handheld
Speccy2021
FGPA Speccy on Digilent Xilinx Spartan-3
FGPA Speccy on terasIC Altera DE1
Horizontal Display prototípus áramkör
Memory to Screen Interface prototípus áramkör
Harlequin prototípus
ULA Replacement prototípus
ULA Replacement
Harlequin Rev. A
Harlequin Rev. D
Harlequin Rev. G
Harlequin Rev. H
Harlequin 128K Issue 1
Harlequin 128K Issue 1B
Harlequin 128K Issue 2B
Harlequin 128K Issue 2D
128K Adapter for Harlequin Rev A
Superfo Harlequin 128K+3 Issue 1
ZX Omni Desktop 128HQ
ZX Omni Laptop 128HQ
ZX Spectrum 128K Remake v0.5
ZX Spectrum Issue 7 PCB
Minimal ZXS for Ulx3s ECP5
Pi Speccy Tape
ZX Spectrum on FGPA with 17 inch LCD screen
Fully integrated ZX Spectrum+
V6Z80P
Pendulum v1.1
Pendulum v1.1b
ZX Spectrum on pipistrello
MCC-216 (S-Video)
MCC-216 (VGA)
MCC-TV
MCC joystick
ZX-Uno
ZXUnCore
Dual-CPU/MCU development board
Aspect 128 AVR ZX Spectrum
Just Speccy 128k
TBBlue by Fabio Belavenuto
TBBlue by Victor Trucco
ZX Spectrum Next CAD file
ZX Spectrum Next rendered file
ZX Spectrum Next prototype Issue 0
ZX Spectrum Next prototype Issue 1
ZX Spectrum Vega
ZX Spectrum Vega+
ReVerSE-U16 Revision A
ReVerSE-U16 Revision C
ZX Max 48 Issue 2
ZX Max 48 Issue 2B
Max 48 Iss2B to Max 128 Is1 upgrade
ZX Spider 48 rev 1.1
ZX Spider 128 rev 1.1
ZX Nuvo 128 Issue 2B
Sparrow Lite prototype 0
Sparrow Lite prototype 1
Sparrow Lite prototype 2
Sparrow Lite prototype 3
Sparrow Lite Rev. 4. mod
Sparrow Lite Rev. 4.
Sparrow 48K Rev. 5.
Beta Disk Interface (aka Beta-48)
Beta Disk 128C v1.4
Beta Disk 128X v1.1
Beta Disk 128 mini v1.1
Beta-128 emu on Arduino Nano
Beta-128 emu on EPM3032 CPLD
Beta-128 emu on STM32F401
SDI-1 v2
ZX128K+2A/+2B FDDI
Multisystem Floppy Interface
Plus D clone (Pablo Jimenez)
Opus Discovery clone (Marian Marzec)
divD80 v1
divD80 v2
MB-01
MB-02
MB-02+ prototype v1.0 and 2.0
MB-02+
Data Gear 2007
MB-02 memory
Single chip 512K SRAM tuning
mod for 29C512 and 29C010 EEPROM
mod for 28C256 EEPROM
MB-IDE 1.0
MB-IDE 2.0
MB-IDE 3.0
MB-03+Ultimate v3.0
MB-02+IDE prototype
MB-04 prototype
ZX-IDE internal
ZX-IDE external prototype
DivIDE 42r2
DivIDE 57
DivIDE 57b
DivIDE 57c
DiwIDE v212
DiwIDE v317 red
DivIDE 2k11
DivIDE 2k14
DivIDE 2k20 AY
DivIDE Revised
DivIDE 2K21 Revised
DivIDE 512
DivIDE 57d2
Joystick module for DivIDE 57x
RTC module for DivIDE 57x
DivMMC by Prato
DivMMC by Bugaj
Kempston daughterboard for DivMMC
PicoDivSD (2015. 02.)
DivSD Nano (2015. 09.)
Just Nano SD Kempston (2020. 05.)
DivMMC EnJoy!
DivMMC EnJoy! mini
DivMMC EnJoy! *Duo*
DivMMC EnJoy! PRO ONE
DivMMC EnJoy! PRO ONE MINI
DivMMC EnJoy! PRO ONE MINI *lite*
DivMMC Future v1.3
DivMMC SinDiKat edition rev.3
SpecSD v1.2
NemoIDE by NedoPC
Z-Controller v1.0
NemoIDE by WCG
NemoIDE by Alex Nemo (aka ZXkit-011)
ZX Tapper v1.0
ZX Tapper v1.4
QqtaDrive
QqtaDrive standalone v1.0
ZXMMC
SerialSucker
ZXMMC+
USB Interface for ZXMMC+
ZX Dandanator! Mini v1.0
ZX Dandanator! Mini v2.0
ZX Dandanator mini DUAL
Multiply v1b
ZX Dandanator AMIE
ZX Dandanator MTD
ZX Spectrum external ROM
Interface 1bis version 1b
Interface 1bis version 2i
Paralell Port Peripheral
System Bus Peripheral
Interface 1bis version 3a
Interface 1bis version 4a
Interface 1bis version 4b
ZX Interface Z
ZXKempstonUSB
PS/2 keyboard adapter on 74HC595
usb2spectrum
Unikeyboard
SpecKey
TOSI Joy Interface
Soundrive Monster
Soundrive TLC7528C
3 channel DA converter for UR-4
3 channel DA converter for Didaktik Gama 192K
4 channel D/A converter sound card
AY internal
AYCKO
Turbo Sound rev.C
Turbo Sound FM rev.C
Turbo Sound Easy
Turbo Sound Mini ABC
ZXM-Soundcard rev 01
ZXM-Soundcard rev 02
ZXM-Soundcard rev 03
ZXM-Soundcard Light
ZXM-Soundcard Middle
FM Magic
Turbo Sound AVR AY emulator v1.0
Kempston + TurboSound
General Sound new version
General Sound memory module
NeoGS prototype
NeoGS revision C
ZXM-GeneralSound
SID-Blaster/ZX prototype 03
DMA Ultra Sound Card
ZXM-CrystalMidi Mini
Sinclair SIF prototype
Olimex ENC28J60-H
SpeccyBoot
Simple Wifi v2.0
Simple Wifi 2 v3.1
ZXNETUSB rev.C3
Original Kempston Mouse
Kempston Mouse Turbo 2005 external prototype
Kempston Mouse Turbo 2006 external
Kempston Mouse Turbo 2006 internal
Kempston Mouse Turbo 2008 external
YPbPr composite video output
S-Video modulator replacement
SLAM128
ZX-VGA-Joy
Programmable Joystick Interface
SotU interface
ZXS Diagnostics Board v2.13
ZX-Tsid rev.A
ZX-Tsid rev.C
Kartusho V4
Interface ROM
PS/2 Keyboard Adapter v1.0
ZX Interface 2.021 revB
ZX Spectrum ROM Cartridge
Superupgrade-upgrade
Internal PS/2 keyboard adapter for ZXS+
SIMM adapter for lower 16K RAM replacement
MSX Video for ZX Spectrum
TEA 2000 replacement daughterboard
Kempston interface v1
Zelux v0.02
ZX ExpBoard Interface
Simple AY Interface
Simple SAA Interface
TwinSound Interface prototype 1
Simple Joy Interface
Simple 8 bit IDE interface
+2A/2B floppy interface
+D clone
Ultimate +2A/2B floppy interface
ZXC1 silver
ZXC1 gold
ZXC2
ZXC3
ZXC4
Spectra interface
Spectra+128
32K Cartridge for IF2 2x16K version
32K Cartridge for IF2 32K version
ZX-Flash Cart
Make it yourself IF2
+D clone
IMAR-3
Repairing cracked ribbon cable
Elongation of short membrane cable
Recostructing of membrane with microswitches
Making new keyboard
Super Cartridge for IF2 TTL version prototype
Super Cartridge for IF2 GAL version
External CF-IDE interface
ROM replacement
External ROM interface
PS2 game adapter
Ear input amplifier
ZX Spectrum smartmedia interface
ZX Spectrum Interface 2 Multirom v3
G-Tech interface
ROM extension
TZX Mouse
JoyTape Player
Reducing the power consumption
Reconstructing the keyboard membrane
ZX Spectrum 48K video output
ZX Spectrum 48K reset button
ZX Spectrum 128K additional sound output
SMART Card
SMARTer Card
Quazar ZX/SAM ROM Cart
Internal CF-IDE interface
ZX-HD HDMI interface prototype
ZX-HD HDMI interface
ZX-AY interface
K-Mouse Turbo 2017-LP interface
Kempston joystick interface
ZX Spectrum +2/+2A/+2B/+3 joystick adapter and Atari compatible joystick tester
PlusDlite floppy interface
Assembled Harlequin board Rev. G.
Speccy Breadborad v1
ZX Spectrum 16/48K membrane by Ben Versteeg
ZX Spectrum 48K+/128K membrane
Memory LED map
Bi-color segment modification
Bank LED map
Simple AY interface
Nice board
ZX128K and ZX128K+2 mod for D40 D80 cooperation
Melodik2
Keyface internal
Keyface external
Repair of ZX Spectrum keyboard inputs
Alternative PSU mod for Didaktik Gama
ZX Spectrum DC Converter
Ultimate bus splitter
MKAY
AmpY
pEAR for 128K+2
pEAR for 128K+2A/B
pEAR 48/128
Angry Space Invader Dual Joy 2012 white
Angry Space Invader Dual Joy 2019
ZX Spectrum 48K/48K+ Z80 and RAM replacement
Penguin PS/2 keyboard interface
ZX Dandanator MTD
ZX Breadboard Adapter
ZX Speccy Breadboard
ZX Speccy Extender
ZX Fixer
IDS2001 clone
IDS2001 clone plus
Beta 128 Plus Disc Interface
Power switch
Composite video output version 1a
Composite video output version 2a
Stereo audio output
Atari compatible joystick connectors
32K High Memory SRAM Replacement (full size IC)
32K High Memory SRAM Replacement (half size IC)
16K to 48K Memory Expander
TK90X RGB circuit
TK90X A/V Reloaded circuit
TK90X Ear Reloaded circuit
TK90X Ear Reloaded 2.0 circuit
TKlado
Multicore 2+
Drive swap switch
Flash ROM adapter prototype v01
Flash ROM adapter prototype v02
Flash ROM adapter
Flash ROM adapter Second Edition prototype
S-Video out
ZX Keyboard
Spectranet
Beta-128 clone by Pavel Cejka
Beta-128 clone by Piotr Bugaj
48K composite video output
SRAM replacement for lower 16K
vLA82 v1
Click keyboard
