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FamicomBox BIOS conversion
http://forums.nesdev.com/viewtopic.php?f=2&t=16991
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Author:  togemet2 [ Mon Jan 29, 2018 5:43 am ]
Post subject:  FamicomBox BIOS conversion

Hello! First thread here. So I guess I'll just plop it here for now. Hopefully it's the right area for something like this.

I recently got my hands on the original FamicomBox BIOS and would like to get it running on NES emulators and real hardware. So far I've managed to get games which were released for the FamicomBox to work (Donkey Kong, Popeye, etc) by compiling the .prg and .chr files into a .nes format. All of those work fine, except for the BIOS splash screens themselves. Whenever I try, the emulator just completely hangs.

So far, I've only got the BIOS and games to work on MAME emulators without any problems so far. After a bit of talking, I found that the FamicomBox expects 8K of RAM at 0000-1fff, and the NES usually has 2k of RAM in there. The bios also uses RAM above 07ffh because it gives the game 0000-07ffh (the usual RAM range). this way the bios can keep bookkeeping and stuff in the RAM without it getting erased by a game.

Would it be possible to modify the emulator itself? Or perhaps hack the BIOS in such a way where they can be displayed?
Thanks. ~togemet2.

Author:  tepples [ Mon Jan 29, 2018 7:30 am ]
Post subject:  Re: FamicomBox BIOS conversion

Would it be practical to hack the BIOS to move all $0800-$1FFF accesses to expansion RAM at $6800-$7FFF?

Author:  togemet2 [ Mon Jan 29, 2018 4:40 pm ]
Post subject:  Re: FamicomBox BIOS conversion

Even after that, the ROM just seems to hang on a black screen. (That's if I did it correctly though).

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