blackjetrock / pico-sp0256

Rp Pico emulator of the SP0256 speech synthesiser chip

Rp2040 Emulation of the SP0256-AL2 IC

Despite the name, this projects does not use the RP Pico. It is a PCB that has the footprint of the 28pin SP0256-AL2 IC. It plugs in to the same footprint as the IC and performs the functions that the IC does. Well, some of them:

1. Has allophones of the SP0256-AL2 as audio samples
2. Responds to the ALD signal falliung edge, latches the allophone nyumber and plays it.
3. Drives the LRQ line

It does not:

1. Handle an external ROM
2. Handle the play allohone on address line going to 1 mode.

This version of the code and PCB is designed to replace an SP0256-AL2 based psion organiser II speech adapter. It will need testing and adjusting in other uses. It should be treated as a work in progress.

This project builds on the work of two other projects the first is here:

https://github.com/ExtremeElectronics/SP0256-AL2-Pico-Emulation-Detail

and contains code that drives the PWM to generate the audio from the phoneme data which is at this project:

https://www.cpcwiki.eu/index.php/SP0256_Allophones

These two projects have been combined and then added to in order to do the emulation of the SP0256 IC itself, such that it can be placed into the footprint of one of those ICs.