I somehow broke audio in Startropics 1 and 2. I just get a weird, repeating, non-discernable noise. All other games work fine as far as I can tell. Do these games do anything special?
The rest of the game appears to work fine, just the audio is broken.
Noise is coming from the Noise channel. Go figure.
Typical APU writes are:
$10 = $00
$11 = $00
$17 = $40
$15 = $0f
$15 = $00
$11 = $50
This part repeated at the start of every frame and no other writes.
$15 = $00
$15 = $00
$15 = $08
$0c = $00
$0e = $01
$0f = $08
$15 = $08
$0c = $00
$0e = $01
$0f = $08
$15 = $00
Figured it out. It has something to do with disabling/enabling WRAM.
Docs say that it is not MMC3, but MMC6. That explains it. I'll hit this up later tonight.