[sdiy] TI 76477 Space Invaders sound chip detailed analysis

John Speth john.speth at andrews-cooper.com
Wed May 23 19:01:04 CEST 2018

I got the chip from RS in the 70’s.  It was fun to play with but compared to what one can do today, it’s just a historical novelty today.  I still have that chip plus the folding paper that was stapled to the back of the card.


From: Synth-diy <synth-diy-bounces at synth-diy.org> On Behalf Of cheater00 cheater00
Sent: Tuesday, May 22, 2018 9:16 PM
To: synth-diy mailing list <synth-diy at synth-diy.org>
Subject: [sdiy] TI 76477 Space Invaders sound chip detailed analysis

I've just found this while surfing the internet, an analysis of the 76477 sound chip's digital sound circuits. This includes the unique shift-register based noise circuit, as well as the noise filter circuit (which is analog):


Here's an earlier anysis of the analog circuitry:


I wonder if anyone has tried cloning the chip for synth use, with modern features like eg tuning.
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