Made some minor changes to the STM32 firmware today and was finally able to test some real-life code for the SNES. It's a small set of instructions that's supposed to color the screen completely green. This screen isn't green, I know that. :) But it's not too far off!
If you look at this output of bsnes, you can see what I was expecting to see:
But I did not write or invent this code, and if I load it in bsnes with accuracy mode, it looks like this:
And after a reset it looks like that:
So, I think it's safe to say that the pitch green image is a product of emulation errors because a more accurate emulation also shows a random image.
Going to test a sound sample next.
As I said, it's an interesting world where a picture like this can be considered success. :D