Square wave with sweep and 4 duty cycles
Square wave with 4 duty cycles (no sweep)
Programmable 4-bit wave channel with custom waveform RAM
LFSR-generated noise for percussion
The Game Boy's built-in audio runs on the Sharp LR35902 CPU with 2 pulse channels, a programmable wave channel, and a noise channel. Despite only 4 channels, composers created remarkably complex arrangements.