Awhile back, I found an official SNES multitap schematic, but recently I've been looking for one for the NES, but haven't been able to find one. I own a NES Four Score, so I opened it up, but it looks like it's built around a Hori-branded ASIC, so it's not much use in terms of building my own... so does anybody know of an official schematic anywhere, or at least understand the low-level communication protocol for the purpose of RE'ing it? If it's anything like the SNES multitap, it probably uses one or both of the otherwise unused pins on the controller port, so finding a cable that will work is probably gonna be a real pain, but it's still something I'd be interested in looking into.
The Four Score is fully documented on the wiki.
It's not complicated; you could implement it with something like two shift registers, two independent one-of-three multiplexers, and a little bit a glue logic, but it's enough separate parts that it's probably easier to implement in a CPLD.
"Hilariously", it doesn't use D3 or D4, merely the same pins as the ordinary NES controller.
It's not complicated; you could implement it with something like two shift registers, two independent one-of-three multiplexers, and a little bit a glue logic, but it's enough separate parts that it's probably easier to implement in a CPLD.
"Hilariously", it doesn't use D3 or D4, merely the same pins as the ordinary NES controller.
lidnariq wrote:
"Hilariously", it doesn't use D3 or D4, merely the same pins as the ordinary NES controller.
I really hoped it didn't... means I can build one using cheap "extension cables" that only have the 5 wires in it, which is really handy
And thanks for the link. That's pretty much everything I needed. I also found nocash's docs on the protocol, so that helped too.