does anyone know of the patent documents for mmc1 ? and perhaps any other patent documents that could be usefull ? i assume since they are avaliable on the web, they are fine to post here? i found one that was usefull for the ppu.
matt
The "MMC1 patent" document is not useful, as it describes a chip which works almost like the MMC1 but not exactly - it describes a mapper which takes 7 writes in a row, using the last 2 bits to determine the register (instead of using the A14/A13 directly). The only mapper which has been patented is UNROM, and that's incredibly simple; there's a document that describes what appears to be MMC5 sound, but that's all it covers (and it may not be accurate).
There are some other ones on a Japanese site (specifically, one for the MMC2), but I don't remember where the site is.
thanks Q. if you or anyone else knows of more mmc1 docs, please let me know. i got some of it working but needs work.
matt
Some of the info at
NESdevWiki might be more up-to-date.