nesdev.org

I'm interested to know if the CPU really does have 4 T states to a single cpu cycle or if that was just assumed from some docs. Similar to docs for the z80 that are incorrect and/or don't give the T state counts or reduced/extended T states for some situations.

Woohoo

I always felt it was the perfect console to learn on (the GB more than the GBC) and still do. The hardware is very simple and easy to understand (especially the video interfacing), the no$cash debugger is pretty adequate, and the cpu is fairly popular and easy to understand. Though I already had exp...

http://mednafen.sourceforge.net/releases/ - Right under change log is the link to the sources/builds. It's modified VBA source I believe.

Demon Sword is the only game I can think of that used that feature to it's advantage in a couple songs (title screen and boss fight, I think). Oh cool. I love finding out stuff like that :D How some games used methods and exploits like that to create new <sounds/graphics> that you normally don't se...

Adding a GB/C forum like the SNES would sounds cool. I mean, since this forum is pretty active.

It might help to take a lot at mednafen's source? I still have my flash card for GB/C and can dig it out if you need some testing done (you write the code ofcourse - I've got a lot I'm still working on )

One of the PCE ROM types has an additional 32k of ram. I'd use that configuration or put it into a CDROM project where it's all ram. The PCE has plenty of open bus areas in the upper 2meg range where I can easily map in some extra ram, but I doubt I can convince any PCE emulator authors to support i...

Oh, that's not too bad. Hardware volume envelope isn't that much anyway. I'd just used fixed volume and handle the envelope in software. Lot of systems use(d) 60hz tick envelopes. I take it that it resets the phase of the duty cycle too? If so, and with the use of an external timer/irq, you could do...

skrasms wrote:but the sound engine has that nasty retrigger any time the upper 4 frequency bits update.

I'm not familiar with this side effect( not vibrato, I know what that is). You get some sort of unwanted sound artifact when updating the period system at a higher rate or something?

I still have lots of downloaded material/docs/etc from when the GBC dev scene was booming. There's *tons* of redundant info though. Everything you probably need to know is at the no$cash link. It's too bad the PCE wasn't a little faster. I'd try to emulate the original GB :D Who knows, I still might...

Klax uses scrolling trickery to reduce 16x16 pixel attribute cells to 16x8 so that the 16x8 pixel playfield objects can be individually colored. Awesome! Thanks for the bit of info. It's the first that I know. Definitely changing the selected nametable is simpler. It's easy to get 4 nametables, so ...

Well, say you have a tile map that can hold 4 screens (since I mentioned NES - lets assume 4 separate nametable mode). If on every 2nd scanline you reposition the X/Y regs to point to a different section of the 4 tilemaps, you can create 16x2 pseudo tiles - thus lessening the color requires per tile...

Just wondering if any demos or games used the hsync tilemap repositioning trick to overcome the colors per tile limitation? That or for limited transparency effects.

IIRC, there wasn't much added for the GBC upgrade. Heh - but it's been a long time since I've touched GB/C dev. CPU speed, another bank of vram, an additional DMA mode or something. That's all I can remember. Anyway... The GBColor cribsheet should give you the memory mapped registers you're looking ...