Zx81 with early ula slightly unusual blog post today. Using programable logic, fpgas, cplds etc to replace and enhance the ula used in the original. Afterwards i got many comments that for a kit it was too difficult to build due to the use of smt. Minesweeper for your zx81 will also run under zx81 emulator xtender.
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. 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. V9938v9958 to tms991829 pcb adaptor msx resource center. The vla81 is a modern plugin replacement for the zx81 ula. 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. The zx spectrum 16k48k ula went through multiple revisions and is either a 5c or 6c series ferranti ula. I didnt have enough space to fit the keyboard interface so it was pretty useless, but it did boot.
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. It is one of several ula replacements charlie has made for members of the sinclair computer family including the vla82 for the. I dont know if the original zx81 ula diagram is available, but you. Altera quartus ii sp1, ne koristite noviju nerziju, jer ne podrzava fpga cyclone ii, cpld max i max ii. Sinclair hardware pagepage with a lot of interesting hardware projects. Zx81 ula logic isnt very complex a few counters, a few flipflops, an 8 bit shift register, and some logic tying things together. Zx81 games the following is a list of zx81 games in the centre for computing history collection.
In 1981, sinclair research released the zx81 as a followup to their earlier zx80. Tested with an extensive suite of zx spectrum software full list to follow. Minesweeper for your zx81 will also run under zx81emulator xtender. Sinclair zx81 zxvid composite video ula fix rwap software. In place of a dedicated monitor, the zx81 was designed to output video to standard television set. 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. 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. Andy reas zx81 ula replacement which lead to his later pld based design chris smiths book the zx spectrum ula. The sinclair zx81 support pageenglish my page boasts new software for the zx81, zx81pc converters hr games. 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. Ula chip ula2c184e 8226 handled several functions for the sinclair zx81, such as detecting keyboard activity, synchronizing the display, and processing the audio. The cost of running this website is covered by advertisements.
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. Games and entertainment software for the zx spectrum. Furthermore would fit the zx80, zx81, jupiter ace currently implemented too and some arcades than only have a single z80 like pacman. Recoil retro computer image library decodes amiga, amstrad cpc, apple ii, atari 8bit, atari portfolio, ata. The idea is to build something along the lines of a zx81, using standard components i. The heart of the zx spectrum series of computers is a custom chip called the ula uncommitted logic array. Zx81 software adverts in computer magazines were often a very crude affair. Zx81 collection, the largest online collection of sinclair zx81 and ts games, software, books and hardware. Grant searles build your own zx80 and zx80 to zx81 conversion.
Cpu, rom, ram and ula a custom logic chip that incorporated all functions of 74xx logic of zx80. 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. Regarding the sam, in fact it is already implemented partially. It works, apart from some z80 timing flaws, it loads software via audio in very well. Zx81 ula, in particular those that do not generate a period of black level voltage the back porch following each line synchronisation pulse. The computer was cheap in uk, it was available as diy kit or assembled one. 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. 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. Its not easy to make all those corner cases work correctly.
Z81 a zx81 emulator for vga pcs running linux xz81 a zx81 emulator for x z81txt a textmode zx81 emulator for the linux console. The zx81 is a home computer that was produced by sinclair research and manufactured in. Ulaplus is a plugin replacement ula for the zx spectrum which increases the total palette to 260 colours. If you are handy with a soldering iron then you can build a zx81 out of. Using programable logic, fpgas, cpld s etc to replace and enhance the ula used in the original. Products for the sinclair ql, z88, zx spectrum and zx81 home. 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.
This 40pin integrated circuit, a ferranti ula2c184e or ula2c210e, was described in the zx81 manual as the machines dogsbody. Base plate i can supply a clear perspex base plate as shown in the pictures to mount the minstrel and keyboard, or. Early sinclair zx81 software adverts retro games collector. 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 zx97lite is a simplified zx97 designed to fit on one single sided pcb. Another has the ula programmed into a more modern cpld. The ula uncommitted logic array is a chip which controls most of the interfaces between the z80 cpu and peripheral functions. This document complements a video presentation, in which the operation of each circuit is. Using the jsmess emulator, users can boot up an emulation of the given title and use it in their browser. This is an implementation of the sinclair ula chip, found in zx spectrum microcomputers. 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. The zx81 was manufactured by the timex corporation and sold as a kit. 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.
Yes, the plan is this board can be installed in a zx81 case and makes this a zx81 replacement. 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. One year later, they released the new and improved zx81. 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. 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. Zx81 software ecosystem is rather limited it is actually possible to test all software of interest. 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. 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. Zx81 ula replacement which lead to his later pld based design. Products for the sinclair ql, z88, zx spectrum and zx81. The zx81 was the successor to the zx80 and one of the cheapest home computers. It was gerts first computer, so it was a natural choice for him to try to emulate. User selectable memory mapping allows the zx97l to boot directly from user mc code in ram. Tested with an extensive suite of zx81 software full list to follow.
Zx97 with schematics and pcb and much much more roger dipaolo. At that time it was not very educative on the hw side as all interesting was stuffed inside the ula chip. 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. Theyve produced a prototype of a zx80 in the form factor of a zx81 main. It runs the current program for only about a quarter of the time in effect. 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. The zx81 is a home computer that was produced by sinclair research and manufactured in dundee, scotland, by timex corporation. The sinclair zx81 was able to be manufactured at such as low cost largely due to the ula the uncommitted logic array. Minesweeper is written by zxteammember bodo in pure basic. Requires the zx81 membrane connectors from the connectors option. Forth is much faster than basic and facilitates the development of. 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. Nowadays you can develop software for the zx81 also in c with the compiler z88dk, but it requires a another computer. Zx81 ula is by far not as complex a chip as a tms9918 total is equivalent of around 15 or 16 ttl ics.
Jul 24, 2011 zx81 on ep2c5t144 mini development board based on zxgate, t80, zx97 projects. The sinclair zx81 has a singlecore z80 processor running at 3. Tricky art of finding parts for retro computers part 2. 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. Download software for zx81 and emulator sinclair zx81 zx80. But once youve covered those bases, theres near0 chance of surprises later on. Minstrel zx80 clone from tynemouth software on tindie.
The aim of this project is to build a zx81 ula equivalent circuit using discrete components that are readily available. Provides the same functionality as the 2c210e sinclair ula. Understanding how everything works together in a zx81 is the hard part imho. My site is the home of my new java zx81 emulator, jzx81. Tynemouth software llp old computers, new computers, bespoke web design and software development, computer repairs, it and media services uk. If you have any games or software that you would like to donate to our collection, please view our donations page. This ula was responsible for the zx81s low chip count. This means you can take a dead zx81 where the ula has failed and drop in this board as a replacement. 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. The complete system used a pair of srams, real z80 and the sinclair rom in flash. Designed as a lowcost introduction to home computing, the zx81 was designed to be small, simple, and cheap. Jun 18, 2019 vla8182128 now all available on sellmyretro. 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. Zx81 had no moving parts the keyboard was membranebased, there was no power switch or advanced outputs.
If you like it please feel free to a small amount of money to secure the future of this website. It is not an exhaustive list of and other games may have been published. 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. 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. Any discussions related to the creation of new hardware or software for the zx80 or zx81. Tynemouth software did for a classic sinclair micro. The sinclair zx81 was released by sinclair research limited on 5th march 1981 as an upgraded version of the sinclair zx80. Dec 31, 2016 zx81 rom, zx81 membrane, zx81 sized board. Zx81 supplies in europehere you can buy zx81 kits and bits spike. Ive not tested if the programs in basfiles can be converted back to pfiles. The ula chip, described by the zx81 manual as the dogsbody of the. 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. It needs a sinclair zx81 or emulator equipped with 32k ram you need to enter the commands.
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