see Sound
Registers
AUDF0 $17
AUDF1 $18
Stella
These addresses write data into the audio frequency divider registers. D4 D3 D2 D1 D0 30KHz divided by 0 0 0 0 0 no division 0 0 0 0 1 divide by 2 0 0 0 1 0 divide by 3 ... ... ... ... ... ... 1 1 1 1 0 divide by 31 1 1 1 1 1 divide by 32