Coda write:

it uses $4011 to do cpu
cycle-timed software mixing at around 12khz (different rate, and
different driver for each number of PCM channels from 1 to 4) and
supports some basic instrument macros like mml/famitracker. the cpu
cycle timing actually causes the pitch to vary slightly relative to
the PSG channels across different players, but not
catastrophically. of course whatever the driver does also causes
seeking to break in many players. Downloadand info.