Audio Memory

The audio processing unit ("APU") in the system has 4 channels, and 4 voices per channel. each channel plays a different, non-configurable, type of wave, each channel plays a different wave:

OLD:

Ch #	Wave type	Byte indexes from 0x3000
Ch 0	Square	0x00, 0x01, 0x02, 0x03
Ch 1	Triangle	0x04, 0x05, 0x06, 0x07
Ch 2	Sawtooth	0x08, 0x09, 0x0a, 0x0b
Ch 3	Sine	0x0c, 0x0d, 0x0e, 0x0f

The high nibble of each byte holds an index into a table of frequencies (APU_PITCH_TALBE) the low nibble holds an index into a table of volume levels (currently not implemented)

NEW DESIGN (old one fucking sucks):

Ch #	Wave type	Format
Ch 0	Square melody	pitch table
Ch 1	Triangle	pitch table
Ch 2	Sine wave	pitch table
Ch 3	Noise	pitch table
Ch 4	Reserved	Reserved
Ch 5	Pulse wave	speed table
Ch 6	Square misc	pitch table
Ch 7	Triangle melody	pitch table
Ch 8	Triangle misc	pitch table
Ch 9	Pulse wave #2	pitch table
Ch 10	configuration byte	config