Audio
(ARM7 only)
| Address | Name |
| 0x04000504:16 | SOUND_BIAS |
SOUND_BIAS is just a 16 bit? bias value. The BIOS function that adjusts it does so slowly (delay between each adjustment up or down), and only to two targets (0 and 0x200.) I can manually set it from 0x000 to 0x3FF, but there is an audible click when changing it fast.
Seemingly audio related, but pretty much unknown regs so far:
| Address | ffff | 0000 | Name |
| 0x040004?0:16 | 837f | 0000 | ? |
| 0x040004?2:16 | ff7f | 0000 | ? |
| 0x040004?8:16 | write-only? | channel(r0).hw8 = 0x10000 - r1 in metroid |
? ranges from 0x0 to 0xF, smells like 16 channels
| Address | ffff | 0000 | Name |
| 0x04000500:16 | bf7f | 0000 | ? |
| 0x04000508:16 | 8f8f | 0000 | ? |
| 0x04000510:32 | 07fffffc | 0000 | ? |
| 0x04000518:32 | 07fffffc | 0000 | ? |
508:16, b7 is tested
SoundRelated1 sets the low 4 bits for either 508 or 509 (as a byte), based on 4 seperate input parameters, 508 is related to 510, and 509 to 518 (channel<<0 and channel<<3)
Dunno if these are sound either, but the BIAS register is right here.