Programmable Sound Generator

This is based on Arnim Laeuger's VHDL implementation of the SN76489. This chip was used in the ColecoVision and the BBC micro.

It is simpler than the popular AY-3-8910/YM2149 chip, having no envelope generation circuitry. That task is left to software. Although an extra chore for the CPU, software can be much more sophisticated. The BBC micro handled envelopes with its firmware SOUND command.

Resource consumption is roughly like so:

Selected Device : 2s300epq208-7 
 Number of Slices:                     134  out of   3072     4%
 Number of Slice Flip Flops:           116  out of   6144     1%
 Number of 4 input LUTs:               225  out of   6144     3%

So less than half the FPGA resources of the AY-3-8910. Modern memory chips have plenty of room for storing envelope generation firmware.