Each channel has five logical registers, NRx0-NRx4, though some don't use NRx0. Sound registers are mapped to $FF10-$FF3F in memory. The master volume of the left and right outputs can also be adjusted.ĭifferent versions of the Game Boy sound hardware have slightly different behavior. Each channel can be individually panned to the far left, center, or far right. Each channel has a length counter that can silence the channel after a preset time, to handle note durations. The squares and noise each have a volume envelope unit to help with fading notes and sound effects, while the wave channel has only limited manual volume control. The first square channel also has an automatic frequency sweep unit to help with sound effects.
Each has some kind of frequency (pitch) control. The Game Boy has four sound channels: two square waves with adjustable duty, a programmable wave table, and a noise generator.
