Designed as a lowcost introduction to home computing, the zx81 was designed to be small, simple, and cheap. Base plate i can supply a clear perspex base plate as shown in the pictures to mount the minstrel and keyboard, or. Download software for zx81 and emulator here i will present some nice software for your zx81 which is written by zxteam members and cannot be found in other sites. This replaces the inner workings of the um1233 tv uhf modulator built into the zx81 to provide a stable composite video out, plus fixes the missing back porch latch issue on some ulas which causes black text on a very dark screen. Minstrel zx80 clone from tynemouth software on tindie. It needs a sinclair zx81 or emulator equipped with 32k ram you need to enter the commands.
Forth is much faster than basic and facilitates the development of. The zx81 is a home computer that was produced by sinclair research and manufactured in. The sinclair zx81 was able to be manufactured at such as low cost largely due to the ula the uncommitted logic array. Cpu, rom, ram and ula a custom logic chip that incorporated all functions of 74xx logic of zx80. The idea is to build something along the lines of a zx81, using standard components i. Understanding how everything works together in a zx81 is the hard part imho. Ula chip ula2c184e 8226 handled several functions for the sinclair zx81, such as detecting keyboard activity, synchronizing the display, and processing the audio. Tynemouth software did for a classic sinclair micro.
Ive not tested if the programs in basfiles can be converted back to pfiles. Sinclair was able to make huge manufacturing savings by the inclusion of a custom ferranti ula or glue chip that connected the other components together in a way that made them do more than they otherwise would. Zx81 collection, the largest online collection of sinclair zx81 and ts games, software, books and hardware. Z81 a zx81 emulator for vga pcs running linux xz81 a zx81 emulator for x z81txt a textmode zx81 emulator for the linux console.
Ive talked about that a few times before, its basically all the chips on the zx80 that werent the rom, ram or cpu rolled into one. Several years ago i implemented most of the 48k ula in vhdl on a max7000 cpld, mainly as an exercise to brush up on my hdl. This document complements a video presentation, in which the operation of each circuit is. Jul 24, 2011 zx81 on ep2c5t144 mini development board based on zxgate, t80, zx97 projects. We have now launched the zxvid module for the sinclair zx81. Zx81 ula replacement which lead to his later pld based design. It is not an exhaustive list of and other games may have been published.
Its probably still the case that the only highlevel language except basic that can be used on the zx81 is forth. Games and entertainment software for the zx spectrum. It was manufactured by timex in dundee scotland and designed to work on a standard television set and although still available in kit form, could be also purchased ready assembled. The zx81 ula also added some extra functionality over the zx80, so its. If you have any games or software that you would like to donate to our collection, please view our donations page. Early sinclair zx81 software adverts retro games collector. Provides the same functionality as the 2c210e sinclair ula. The zx97lite is a simplified zx97 designed to fit on one single sided pcb. It seemed the fist stage was just to try to build up the zx81 circuit away from a zx81 board, but using the original zx81 chips.
The complete system used a pair of srams, real z80 and the sinclair rom in flash. Tested with an extensive suite of zx spectrum software full list to follow. This means you can take a dead zx81 where the ula has failed and drop in this board as a replacement. The aim of this project is to build a zx81 ula equivalent circuit using discrete components that are readily available. Zx81 software ecosystem is rather limited it is actually possible to test all software of interest. After the vla1 was completed i set myself a challenge to replicate the functionality of some of the other sinclair ulas, firstly the zx81 followed by the zx spectrum and finishing with the toastrack ula as this would leverage most of the zx spectrum ula design. Any discussions related to the creation of new hardware or software for the zx80 or zx81. Zx81 ula, in particular those that do not generate a period of black level voltage the back porch following each line synchronisation pulse. A gate array is an approach to the design and manufacture of applicationspecific integrated circuits asics using a prefabricated chip with components that are later interconnected into logic devices e.
And software distributed on the front of computer magazines on a thin. Extending life of technology who are rwap software rwap software a division of rwap services was set up in 1986 to help develop and improve the range of software being developed at the time for the sinclair ql home computer. The internet archive software library is a large collection of viewable and executable software titles, ranging from commercially released products to public domain and hobbyist programs. The zx97l is a complete zx81 using discrete logic chips with 32k of battery backup ram and 32k of eprom. Oh it quite possible to build a clone around a cpld based ula, i did such a thing, used even less passive components that the original, properly split the databus and addresss bus, so that got rid of 17 resistors for a start, tr1 circuit on the cpld, so that anothe few components gone. Ulaplus is a plugin replacement ula for the zx spectrum which increases the total palette to 260 colours. The sinclair zx81 has a singlecore z80 processor running at 3. Sinclair hardware pagepage with a lot of interesting hardware projects. In 1981, sinclair research released the zx81 as a followup to their earlier zx80. Zx81 ula is by far not as complex a chip as a tms9918 total is equivalent of around 15 or 16 ttl ics. If you like it please feel free to a small amount of money to secure the future of this website. Recoil retro computer image library decodes amiga, amstrad cpc, apple ii, atari 8bit, atari portfolio, ata. Regarding the sam, in fact it is already implemented partially.
Yes, the plan is this board can be installed in a zx81 case and makes this a zx81 replacement. Zx81 ula logic isnt very complex a few counters, a few flipflops, an 8 bit shift register, and some logic tying things together. The zx81 has the same microprocessor and runs at the same speed as the zx80, but it has a better basic programming language and is cheaper to produce, due to having fewer chips and a. The ula uncommitted logic array is a chip which controls most of the interfaces between the z80 cpu and peripheral functions. Tynemouth software llp old computers, new computers, bespoke web design and software development, computer repairs, it and media services uk. Nowadays you can develop software for the zx81 also in c with the compiler z88dk, but it requires a another computer. We have continued to grow and expand our range of products and services to encompass new technologies as they have emerged, whilst keeping our roots firmly in the world. Using programable logic, fpgas, cplds etc to replace and enhance the ula used in the original. Zx97 with schematics and pcb and much much more roger dipaolo. Minesweeper for your zx81 will also run under zx81emulator xtender. Minesweeper is written by zxteammember bodo in pure basic. The zxula2 was born, which uses modern, easily obtainable parts, to provide the zx81 with a replacement ula, which has composite video out, plus a turbo mode to make the zx81 run even more quickly the company has also been instrumental in getting replacement keyboard membranes reverse engineered for a range of computers, including the zx. This was a technology pioneered by ferranti, of which sinclair was one of the first adopters incorporating all of the discrete logic of the zx80, plus a nmi generation circuit into the initial zx81 2c158e ula. Minesweeper for your zx81 will also run under zx81 emulator xtender.
My site is the home of my new java zx81 emulator, jzx81. The heart of the zx spectrum series of computers is a custom chip called the ula uncommitted logic array. It was gerts first computer, so it was a natural choice for him to try to emulate. But once youve covered those bases, theres near0 chance of surprises later on. This is an implementation of the sinclair ula chip, found in zx spectrum microcomputers. Now all we need is the details of whats inside the ulas the hard bit the new fpgaula would probably run a lot cooler and be a hell of a lot more reliable then the originals. Its not easy to make all those corner cases work correctly. Using programable logic, fpgas, cpld s etc to replace and enhance the ula used in the original. Zx81 with early ula slightly unusual blog post today. I dont know if the original zx81 ula diagram is available, but you. Grant searles build your own zx80 and zx80 to zx81 conversion. Download software for zx81 and emulator sinclair zx81 zx80. Zx81 had no moving parts the keyboard was membranebased, there was no power switch or advanced outputs. Altera quartus ii sp1, ne koristite noviju nerziju, jer ne podrzava fpga cyclone ii, cpld max i max ii.
One year later, they released the new and improved zx81. The computer was cheap in uk, it was available as diy kit or assembled one. Zx81 software adverts in computer magazines were often a very crude affair. User selectable memory mapping allows the zx97l to boot directly from user mc code in ram. At that time it was not very educative on the hw side as all interesting was stuffed inside the ula chip. Furthermore would fit the zx80, zx81, jupiter ace currently implemented too and some arcades than only have a single z80 like pacman. I was reading that the ula in the zx81 effectively replaces discrete logic chips such as 74ls ics found in the zx80, does anyone know how. No modification to the zx81 circuit board should be allowed, and the only connections between the zx81 and the ula replacement should be the 40 pins of the original ula socket. Dec 31, 2016 zx81 rom, zx81 membrane, zx81 sized board. V9938v9958 to tms991829 pcb adaptor msx resource center. We are helping to promote both the sinclair zx80 zx81 and the sinclair ql through development of new websites, including the sinclair zx80 zx81 forums and the sinclair ql wiki which help to increase the amount of information available on the internet about these computers, and enthuse people into developing new hardware and software products.
It works, apart from some z80 timing flaws, it loads software via audio in very well. Another has the ula programmed into a more modern cpld. Still very much in the time of the bedroom coder much of the software in this early period was still produced at home using rudimentary tape to tape copying machines and photocopied inlays and labels. The zx81 is a home computer that was produced by sinclair research and manufactured in dundee, scotland, by timex corporation.
Products for the sinclair ql, z88, zx spectrum and zx81. The zx spectrum 16k48k ula went through multiple revisions and is either a 5c or 6c series ferranti ula. Plugs into original ula socket, provides composite video output requires vwry small mod to bypass uhf modulator, but still uses modulator output socket but wait theres more. The sinclair zx81 was released 1981 in the uk and later in 1982 in a slightly modified form as the timex sinclair in the united states. Requires the zx81 membrane connectors from the connectors option. Afterwards i got many comments that for a kit it was too difficult to build due to the use of smt. Jun 18, 2019 vla8182128 now all available on sellmyretro. It is one of several ula replacements charlie has made for members of the sinclair computer family including the vla82 for the.
If you are handy with a soldering iron then you can build a zx81 out of. Early sinclair zx81 software adverts home sinclair zx81 early sinclair zx81 software adverts way before full colour ads were the norm and just before the emergence of its colourful sibling. I didnt have enough space to fit the keyboard interface so it was pretty useless, but it did boot. Zx81 games the following is a list of zx81 games in the centre for computing history collection.
This 40pin integrated circuit, a ferranti ula2c184e or ula2c210e, was described in the zx81 manual as the machines dogsbody. Andy reas zx81 ula replacement which lead to his later pld based design chris smiths book the zx spectrum ula. In place of a dedicated monitor, the zx81 was designed to output video to standard television set. It was launched in the united kingdom in march 1981 as the successor to sinclairs zx80 and designed to be a lowcost introduction to home computing for the general public. A 64 macrocell will probably do if all you need is a vanilla zx81 ula replacement. As the xilinx xc9572xl cpld used in the vla81 had unused resources i decided to add some extra functionality see features. The sinclair zx81 support pageenglish my page boasts new software for the zx81, zx81pc converters hr games. The zx81 was the successor to the zx80 and one of the cheapest home computers.
The zxtape software is a simple pc program can be used to send zx81 files from the pc to the zx97l using the same protocol as the zx81 tape load signal at a rate of about 100 bits per second in the fast mode. The crystal frog by gus this is an excellent text only adventure, written for the quill adventure writer, which has now been ported across from the sinclair zx spectrum version by kerian uk limited. There are now over 600 different zx81 software titles listed, which you can run within your browser just click on the play button next to the track to launch the jtyone emulator note. This ula was responsible for the zx81s low chip count. The ula chip, described by the zx81 manual as the dogsbody of the. Tricky art of finding parts for retro computers part 2. The zx81 was manufactured by the timex corporation and sold as a kit. It runs the current program for only about a quarter of the time in effect.
Theyve produced a prototype of a zx80 in the form factor of a zx81 main. The vla81 is a modern plugin replacement for the zx81 ula. Tested with an extensive suite of zx81 software full list to follow. Products for the sinclair ql, z88, zx spectrum and zx81 home. The sinclair zx81 was released by sinclair research limited on 5th march 1981 as an upgraded version of the sinclair zx80. Using the jsmess emulator, users can boot up an emulation of the given title and use it in their browser. The cost of running this website is covered by advertisements. Sinclair zx81 zxvid composite video ula fix rwap software. Zx81 supplies in europehere you can buy zx81 kits and bits spike.
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