nesdev.com

This inc PPUADDR to reuse the PPU's I/O data bus value as a VRAM address is beautiful. Even more dastardly would be inc PPUDATA to exploit the reported inability to write to video memory on consecutive M2 cycles. INC on $2007 is unfortunately not nearly as simple as just ignoring a write. I looked ...

The reason for MMC5's snooping on accesses to $2002, $2005, $2006 (MMC5A), and $4014 isn't known, and MMC5A appears to respond to writes to $5800-5BFF for unknown reasons. Definitely still some mysteries, though nothing that likely matters for existing games.

I spent about 4 hours putting together a proof of concept using MMC1 and 32 KB of CHR-RAM, currently just animating the waterfall. It targets PRG0 (PRG1 will likely require changing some addresses). It uses 4 KB CHR mode and swaps the entire background table at once (between banks 1-4). The automap ...

Zelda 1 uses 8 KB of CHR-RAM, not CHR-ROM, so it'd have to be converted to CHR-ROM to allow the swapping necessary for this (though I don't know if there's anything aside from emulator compatibility that would prevent you from having bankable CHR-RAM on MMC1). CHR-ROM, though, doesn't seem very comp...

Nice findings! Does $40C0.0 control the modem's WRAM, too, or just cartridge RAM? I've seen that official code writes 0 to $40AE before 0 to $40C0.0, and 1 to $40C0.0 before 1 to $40AE. They're always a pair. I've assumed that these enable/disable the modem's WRAM, but I haven't tested this because ...

I don't know the details, but I believe Ridley's behavior in Metroid depends on uninitialized RAM. This causes speedrunners to seek out specific consoles (usually toploaders) or use flash carts with firmware that leaves favorite values in RAM.

The jitter in Steins;Gate is just a matter of the split not being timed properly. I've written a patch to fix it and the other visual issues I'm aware of (split timing with DPCM playing; color artifacts from the palette swap; blacker than black in the palette fades), but have been wanting to play th...

I've been using the INL dumper primarily for Famicom modem carts, which all use MMC1 and mostly dumped fine with the existing MMC1 script. However, a handful of carts didn't dump correctly and would come out different each time, being mostly correct but with bit flips in bytes at certain address off...

What sort of output do you get when you try to dump Mei Tantei Holmes? It looks like a pretty standard MMC1 game, with 256 KB ROM and CHR-RAM. The current MMC1 script is definitely not comprehensive, but I'm pretty sure it should handle that just fine.

Does the older menu cart have different software on it? I'm even more interested in dumps of these now; I'd love to see what's different. FYI, if you want a general-purpose cart dumper, I've been pretty happy with the INL dumper. While it doesn't have scripts for everything yet, it'll handle the men...

Ben and I were able to get reading and writing of the microwire EEPROM to work from test software. Here's the setup you need: - Ensure modem WRAM is off by writing 0 to $40AE and $40C0.0. - Ensure cartridge SRAM is off by keeping $A000.4 high. - Write 0 to $E000.4 to enable EEPROM data out (DO). - W...

Well, you started this conversation by calling the use of file extensions for program association 'stupid' and then kept making prescriptive statements about how things should be done, which isn't exactly useful. Explaining why lets us understand the problems with this system and the value of your s...

A file browser should be able to launch applications based on the content, not the filename. It should also be able to have overrides, both on a per-file and per-directory basis. Applications should always validate the data they are given before doing anything. It shouldn’t trust the filename. In f...

I regularly see assert to mean to make a thing active, whether that's active low or high. I'm in favor of using it in this case. Using the definition instead of the word will certainly be clearer to someone who hasn't encountered this word in this context before, but less clear to people who know th...

This may be wrong, but I'd thought this issue is solved with the volatile keyword, telling the compiler not to cache the variable and that it should be reaccessed on each use.