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POKEY 4-bit sampling and 7800basic

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A little known POKEY trick:


Writing $10-$1F rapidly to one of the AUDCx registers will cause POKEY to replay 4-bit audio samples.  Downside of this is it takes 100% CPU.


Now here's the hard part ... I believe I can down sample to 4-bit audio using Audacity.  How then would I include this data into 7800basic, i.e. read data and convert to 4-bit values to be written as follows:  psound 0,0,1,x ... where x is $00 to $0F


I know 5200 Berserk does this trick for the robot voices, though the game stops while doing so.

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TIA has the exact same trick, with identical resolution. No need to require a pokey for playing samples.


I haven't done this yet in my own code, but Bob has done it a few times. You'd need to use assembly code within 7800basic to update the register, to play the sample.

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