[sdiy] Understanding 80s Synth Architectures

Brian Willoughby brianw at audiobanshee.com
Sun Feb 6 22:46:06 CET 2022

Speaking of macro assemblers, it's clear that some of these synths have firmware that was written with such a tool.

The Oberheim Matrix 12 has some very interesting code. It uses a 6809, so that tends to inspire fancy coding.


On Feb 5, 2022, at 13:27, Mike Bryant <mbryant at futurehorizons.com> wrote:
> Oh there were lots of other languages.  PL/Z for Zilog, PLF for 6800, uPascal for 68000, etc
> All primitive by today's standards though - really nothing more than macro-assemblers.
> -----Original Message-----
> From: grant
> Sent: 05 February 2022 20:50
> I agree it must have been a focused effort to pull that off. As a casual observer I can say that it was most definitely written in assembler (as almost everything was at that time). Your closest HLL would probably have been PL/M at the time (but that was Intel focused).
> GB
> ------ Original Message ------
> From: "rburnett at richieburnett.co.uk" <rburnett at richieburnett.co.uk>
> Sent: 2/5/2022 10:16:02 AM
>> Wow, that is pretty impressive.  And a substantial undertaking to figure
>> out how it all works and then comment it!  How long did that take you!?
>> Do you think the original code was written in assembly, or compiled from
>> a higher level language like C?
>> -Richie,
>> On 2022-02-05 04:10, Anthony via Synth-diy wrote:
>>> In case you're interested in understanding how the firmware of these
>>> 80s synthesisers was implemented, I've done an annotated disassembly
>>> of the Yamaha DX7's firmware ROM. This repository contains a lot of
>>> information regarding how the synth itself functioned, and was
>>> designed. Hopefully it provides a little bit of insight into how
>>> synths in this era were designed! That's the reason I began this
>>> project. I was interested in understanding the exact same topic.
>>> https://github.com/ajxs/yamaha_dx7_rom_disassembly

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