Few issues are extra thrilling to a retro gamer than the invention of an obscure gaming console from the previous that that they had not beforehand heard of. Whether or not it’s the Vectrex, the Atari XEGS, or the Nintendo Digital Boy, these discoveries open the door to some very uncommon, and infrequently very enjoyable, gaming experiences. These which were across the digital block a couple of occasions might imagine that they’ve seen all of it, however likelihood is that there are nonetheless some oddball consoles hidden within the recesses of gaming historical past.
Take the “Z80 TV Recreation,” for example (sure, that’s its precise identify). It was by no means a business product, so it could be a little bit of a stretch to contemplate it a misplaced console — however it does have a library of video games to find. It was first constructed as a homebrew venture by a Mr. Isizu in Japan in 1987, and for the time, it was pretty highly effective. The Z80 TV Recreation was outfitted with a Z80 processor working at 4MHz, 16KB of RAM, and 8KB of devoted video RAM.
The {hardware} (📷: Alex Lowry)
Simplicity was the secret in designing the system. It consists of simply 19 built-in circuits in complete. It outputs a 60Hz composite video sign with 168×210-pixel decision and 1-bit shade. It additionally has 1-bit audio output, and a connector for a single controller. Specifically, it was made to work with a Sega Grasp System gamepad, with its 4-way D-pad and two buttons.
For such a minimal system, the Z80 TV Recreation punches effectively above its weight. The machine’s structure was designed round accessibility. Its deal with house permits for 32KB sport cartridges, with the potential for bigger titles by means of financial institution switching. The system’s ROM and RAM structure is simple: 32KB for the cartridge, 16KB for system RAM, and 8KB for video reminiscence. This clear construction made it straightforward for programmers to know precisely how their code interacted with the {hardware}, which additionally makes the console an awesome platform for training.
The console’s video sync sign isn’t generated by a devoted graphics chip as you would possibly count on, however by an EPROM to maintain the element rely low. The timing of the video output is dependent upon the entry velocity of the ROM chip used, which suggests hobbyists generally need to experiment to discover a chip that produces a clear, steady image. The design additionally accommodates each Intel 8255 and Zilog Z80PIO I/O controllers for dealing with enter and sound, permitting flexibility relying on which chip builders may discover.
Recreation cartridges (📷: Alex Lowry)
Regardless of being a one-off venture, the Z80 TV Recreation has a surprisingly massive software program library. Mr. Isizu himself developed six unique video games, all written in Z80 meeting language, full with commented supply code. Fashionable builders have stored the platform alive because of instruments just like the Z88DK growth package and Inufuto’s Cate compiler, which make it attainable to write down new video games in C. Utilizing these instruments, 20 extra video games have been ported to the system.
Alex Lowry has developed a trendy recreation of the Z80 TV Recreation and shared the schematics and design information wanted to breed it. The elements, just like the Z80 processor, the reminiscence chips, and the 7400-series logic chips, can all nonetheless be bought new at this time, so go take a look at the small print if you wish to make your personal model of this console.
