Wednesday, February 13, 2008

The SP0256-AL2 Speech Synthesizer

One of the first major electronics projects I attempted was to interface a speech synthesis chip, the venerable General Instruments SP0256-AL2, to my Commodore 64 (this was in the late 80's I think). It ended up not being all that hard thanks to excellent schematics in the datasheet and in Robot Builder's Bonanza
The speech chip was a soon-to-be discontinued item I picked up at Radio Shack (I just found a link where you can still buy these). Recently I did some web searches for giggles and I guess people are still using these old ICs but there didn't seem to be a lot of info out there about them.

Since I'm a packrat, I still have the original datasheet that came with the chip. I figured I'd scan it in for anyone out there who lost theirs and are looking for information and details on the chip. (5.2 MB download)

I still have mine on the original breadboard I put it in, with the other components surrounding it like a little forest. At some point I am going to hook it up to my BASIC Stamp 2 and revive it. I never did get the audio amplification working. Afterwards I could interface it to, say, an AVR microcontroller chip and make it accessible to my current and future robots via a much simpler, two-wire, serial I2C interface.


  1. Hello!

    I worked for GI starting in bought up by Motorola a few years back...I still work for them...I had one of these on my desk programmed to say "General Instrument Will Rise Again!" :)

  2. Hi,

    I found a few tubes of NOS, SP0256A-080's in one of my older chip boxes today:) They are used for speech, robot kits etc and pretty hard to find new. They are 86 date codes, and the cost is $12 shipped in the US and $15 worldwide. I can also sell all 30 pcs for $225 shipped worldwide. Here is a little info from the web on the chip:

    The SP0256-080 produces all 59 phonemes of the English language plus 5 pauses of different
    durations. This is the simplest approach to universal speech synthesis and the speech quality makes for a
    good robot voice. Each of the phoneme's speech patterns are individually addressable, making the
    SP0256-080 capable of saying anything that can be said in the English language. This chip is rare and
    getting harder to find! Features: Cool "Retro" Robotic Speech * Stand Alone Operation with inexpensive
    support components * Allophone Synthesis.

    Mark Capps


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