One of the later comments on the article offers custom PCB design to make a test harness for the PPUs. It seems like a perfect partner for a manually controllable clock for the whole SNES, e.g. as Ben Eater's 6502 demos use. If you can freeze the clock at will, you can more easily inspect the data and address lines. But this wouldn't work if the PPU latch timing depends on analog effects or the PPUs have an internal clock.
Combine the test harness with a USB logic analyzer and signal generator, and borrow some concepts from fuzzers like AFL, and it should be possible to automatically identify critical phases of the PPU operations.
Question: do the PPUs themselves generate analog video, or is there a separate DAC whose bus could be tapped to figure out what color the PPU is producing?
Combine the test harness with a USB logic analyzer and signal generator, and borrow some concepts from fuzzers like AFL, and it should be possible to automatically identify critical phases of the PPU operations.
Question: do the PPUs themselves generate analog video, or is there a separate DAC whose bus could be tapped to figure out what color the PPU is producing?