Wondering how filters such as the legendary Supersaw Oscillator works on sound keyboards?

#ccc #c3 #dsp #supersaw_oscillator #hardware #hacking #reverse_engineering #engineering

This is an amazing story … It’s a story about breaking into DSPs (digital signal processors), reverse engineering the algorithms, and finding out how functions are mapped onto silicon.

One of the findings is how the legendary Supersaw Oscillator works! Spoiler: No modulation, no phase shifting and no echo effects!

A team of engineers at The Usual Suspects has been pushing the boundaries of open-source music technology by reverse-engineering the custom silicon behind iconic synthesizers. Following their earlier work on Motorola-based devices, they took on the far more complex Roland/Toshiba TC170C140 ESP chip — the heart of the JP-8000 and its legendary SuperSaw oscillator. Using automated silicon analysis, clever microscopy, direct hardware probing, opcode statistics and fuzzing, they decoded an undocumented instruction set and built a bit-accurate, real-time emulator. Their work uncovers not only how the SuperSaw truly operates, but also demonstrates how modern tooling can transform the reverse engineering process.

Topics covered:

  • Lessons learned from analysing more advanced chips
  • Progress towards automating silicon reverse engineering
  • Finding and exploiting hidden test modes
  • Coaxing the chip into revealing its internal behaviour.
    How the ESP chip compares to known DSPs.
  • What the SuperSaw oscillator actually does.

This amazing work was just presented by giulioz at the Chaos Computer Club (CCC) event 🔥

Talk: https://www.youtube.com/watch?v=XM_q5T7wTpQ

Github: https://github.com/giulioz/

Science With Data //