Speech Synth Reverse Engineered

by on Aug.12, 2010, under Arduino / AVR, Didj, Electronics

After a ton of probing and trace fallowing I have come up with this schematic :)

M14 is the piggy backed roms only one side of the pins of the chip are used

IC2 is the TM5200

Table of WTF magic

now for power im using this circuit

work fine with my arduino, now to get to coding and building an small amp for the sound out

4 Comments for this entry

  • avatar

    This makes me really happy. I had a TI-99/4A as a kid and would have gone crazy if we had owned the speech module. I have seen them floating around for cheap at junk shops and Goodwill computer stores, so it would be awesome to see a mini-revival for these little gadgets!

  • avatar


    I’m currently trying to interface a Speak and spell (who use similar Speech module) with my arduino,
    did you get success getting a interface between the arduino and the speech module ? (especially the way it works with the 4 bit add bus with cs and clock)


  • avatar

    I’m guessing this never materialized? I was looking to add a spare TMS5200 out of the same TI-99/4a module to an automatic pet feeder but the lack of info out there on how to interface with the arduino is stifling.


  • avatar
    Evan Allen

    I have this sorta working, I got the speak command to work. I really want reset, address, and speak external to work. If you have any success with this I’d appreciate it. My progress will be posted to my blog soon (citing this as a source for pinout at very least) and my code will be on github.

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