Summary

For a separate activity, I needed to make a little testing setup where I could record phonemes from an SP0256-AL2 to see if using prerecorded audio would be an acceptable simulation of the actual device.  To do this, I intended to hook up one of my existing physical SP0256-AL2 to a 'BluePill', and send data over the USB CDC serial port.

This was intended to be a throw-away project, but it seemed like it might have some use to someone else, so I have started this project to document such.

Deets

I have to backtrack a little since this activity actually started four days ago.  At that time another hackaday user [Michael Wessel] had skulled one of my other projects -- a TRS-80 emulator.  I noticed he had done some synthesizer work for the TRS-80 Model I physical machine, and I had been meaning to extend my emulator to do similar, but I didn't have manuals.  He sent me a critical page that lists the TRS-80 Voice Synthesizer phonemes and codes, and some other snippets relating to mapping those codes to DecTalk, which he prefers for quality.

This was enough to pique my interest in seeing if I could pull off some sort of simulation in my emulator.  I say 'simulation', because at this moment I didn't plan on emulating the chip (i.e. reimplementing the digital filters and voice model), but rather just try to concatenate pre-recorded phoneme output.  Also, the only chip I have is the SP0256-AL2, which is almost certainly not the chip that was used in the original product anyway.  But maybe I could make a serviceable approximation in the meantime -- my emulator is just for entertainment, anyway.

So my thought was that I should record the set of phonemes from the physical device (which I have a couple of from back in the day).  The device needs some other processor to drive it, so I thought about using my beloved BluePill, of which I keep a small supply on-hand for these sorts of occasions.

Next

Planning...