Over the summer time, it’s possible you’ll recall seeing a homebrew 6502 sport console known as the GameTank grace those pages. The manufactured from [Clyde Shaffer], the gadget was once impressively entire, rather well documented, or even had a budding library of video games.
Not too long ago, [Clyde] took to the r/electronics subreddit to blow their own horns the newest development to the GameTank: a revised detachable cartridge. The most important exchange this time round is the addition of 32 KB of battery-backed SRAM that provides video games (or some other instrument that may well be at the cartridge) some power garage to paintings with.
By using the 8th output little bit of the cartridge’s shift sign up, instrument can transfer between getting access to the Alliance Reminiscence AS29CF160B 2 MB NOR flash chip (which is taking where of a standard ROM) or SRAM. The higher part of the cart’s cope with house is at all times to be had, because it accommodates the 6502’s reset vector. However as soon as the gadget is up and operating, the decrease part of the flash may also be accessed through a sliding “window” in reminiscence that’s managed through the shift sign up.
Including the backup energy supply most effective took the addition of a coin cellular and a pair diodes to verify it doesn’t intervene with the ability being equipped from the gadget when the cartridge is in use. Apparently [Clyde] notes that if a cartridge is put in within the GameTank when the ability is switched off, it can give sufficient juice to maintain the gadget’s RAM — so disposing of the cartridge when now not in use is most definitely a good suggestion.
The GameTank is an out of this world instance of a well-executed homebrew 6502 pc, however in fact the wonderful thing about running with the enduring 8-bit microprocessor is how little it actually takes to get a gadget off the bottom. So in the event you’re having a look first of all one thing a little bit much less complicated, check out this unmarried breadboard implementation we lined not too long ago.