cgram access problems - Githubissues

devinacker / bsnes-plus

debug-oriented fork of bsnes

http://bsnes.revenant1.net

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cgram access problems #281

Closed Redstone-Ghost closed 3 years ago

Redstone-Ghost commented 3 years ago

i was messing about with asm when i noticed cgram can be accessed at anytime. its only supposed to be able to be accessed during vertical horizontal and forced blank. i linked a rom showing this tested on build cgram rom.zip

05.76-master

devinacker commented 3 years ago

CGRAM can be accessed at any time. The only thing that happens when accessing it during active display is that you'll read/write whichever palette index is currently being accessed by the PPU instead of the one selected via $2121.

You can see exactly the same result when running your test ROM on a real SNES:

Redstone-Ghost commented 3 years ago

sorry forgot to uncheck fast ppu when testing in bsnes