Here is some opcode information for the Square channels. I'm not 100% on them, but since there are some people working on songs already, I thought I should throw them out there for experimentation. Let me know if I have anything wrong (let me know if I'm right too
). Again, this is just for the Square channels.
C4: takes one operand. The right side (0-F) is used as the base volume (pre-envelope) for the channel. Not sure about the left side yet.
CD: takes two operands. The first operand can be a value 0-9 and selects the volume envelope. The second operand can be a value 0-3 and selects the duty cycle for your square wave (but backwards. 3 sets the duty cycle to #%00xxxxxx, and 0 sets it to #%11xxxxxx).
Below are the volume envelopes. These envelopes are applied to each note, so for fast notes they will likely be very subtle to the ear. The maximum volume in these envelopes is the base volume set in opcode C4. Please experiment with them:
1: Slow fadedown
2: low to high quick, then fade down (might sound like a pluck?)
3: fade down to half volume, then fade back up
4: fade up from half volume, then fade back down to half
5: fade down fast two times
6: down a little, up a little, then down to 0
7: down a lot, up a little, then down to 0
8: constant low volume, then rises to high, finally drops to half volume
9: fade down to half volume fast two times, then fade from half volume down.
I don't have #0 down in my notes. I must have overlooked it. I think it's not like the others though. I'll have to look it over again later and do an update.