Via CloudOnAFly on this
VSE thread:
"After of 2 hours of working in assembly for the Z80 chip on the Game Boy Color. I have emerged victorious finally gaining access to the synth chip. I made this incredibly gritty buzzing ...square wave... that aside...the hardware is pretty sweet you can make your own wave forms, going to mess with that a little later.
contents of the synth chip:
1 quadrangle wave with sweep and envelope
1 quadrangle wave with envelope
1 noise sound generator
1 custom wave form...
essentially it's beautiful...
ps. assembly is a royal pain"