Lesson P11 - Sound on the Wonderswan The wonderswan has pretty powerful sound for a handheld!... With 4 channels capable of playing digital sound samples, we can create some decent digital music! Lets make a noise!

WSW_JoypadSprite.asm

The WonderSwan sound hardware

Before we can make a sound we need to do two things! First we need to set the base memory address of our sound samples 0D00h, we write 34h to port 08Fh to set the memory address. Next we need to create a wave - We write 16 bytes, one nibble per sample.... We make a square wave by writing a sequence of 0 and F bytes We need to make noise in some cases, so we use Channel 4 in all cases in this example
First we check if AL=0, if it is, we need to turn off the sound. We silence the channels by setting bit 3 to zero of port 090h
Next we set the volume, we only have 1 bit setting our volume in the parameter - bit 6. we set the bits of port 08Bh  to set the volume - 15 is the maximum - 0 is the minimum volume
We need to set the pitch. The Wonderswan uses a 11 bit frequency. We set the pitch using ports 086h (L) and 087h (H)... we only have 6 pitch bits in our chibisound parameter, so we need to bitshift!
If bit 7 of our chibisound parameter is 1, we need to set the noise to on! We need to set the Noise on  with bit 7 of port 090h (we also set channel 4 on with bit 3). We also need to set the noise to ON, and configure it with port 08Eh
If noise is off, we just need to set bit 3 of port 090h to 1 to enable the channel without noise.

Sound channels 2,3 and 4 on the Wonderswan all have different capabilities, but at a basic level they all play digital samples with frequency synthesis.