Very cool! I wonder if it "only" converts the AY registers to the EP-Dave or does it do more to play PT3s?
If you think about 1:1 register conversion then the answer is: do it more.
I used the existing PT3 player code from the net, and AY writes changed to subrutine calls for AY conversion routine, which is developed by IstvanV.
This routine do some calculations for the frequency values, and try to convert the noise usage to Dave noise channel.
The main problem if I know right: the AY have 3 channel, and any channel can play normal sound or noise. Dave have a 3 sound channel and 1 noise channel (all are stereo).
Another problem with the envelopes, AY do it from hw, at the Enterprise no hw envelopes, EXOS SOUND: device do sw envelopes at 50Hz interrupts. This AY emulation routine also try to emulate these in interrupt routine.