Jamin’ to Bach, Commodore 64 style

[thrashbarg] missed the sounds of the Commodore 64 and longed to hear the great masters in 8-bit glory. To get his fix, he created a midi device using the original Sound Interface Device from those long-dead systems. He’s interfaced the MOS6581 SID with an Atmel AVR ATmega8 microcontroller. The receiving pin for the AVR’s UART is used as a MIDI-IN connection, with the microcontroller converting midi data into the proper sound generation specs for the SID. The result is the 10 minutes of [Bach]‘s Brandenburg Concerto heard in the embedded video above.

We have no idea where he picked up this obsolete chip, but if you want to give this a try, perhaps you’ll have some luck emulating the MOS6581 by using another ATmega8.


  1. Ben Ryves says:

    Sounds very nice. If you like this sort of thing I expect you’d also like the arrangements and performances by Walter/Wendy Carlos!

  2. Hirudinea says:

    Damn, does that take me back.

  3. Frank McSteez says:

    “We have no idea where he picked up this obsolete chip”

    Really? First of all, the C64 was the best selling PC ever. Considering that there were tens of millions of SIDs out there in the C64s alone, plus big piles of them elsewhere… well the point is that it’s not hard to find them.

    eBay’s always got them, Kitsch-Bent usually has lots ( http://store.kitsch-bent.com/ )

    And to any chiptune artists, a SID is far from obsolete.

  4. adam says:

    The midibox project has a very cool looking/sounding synth project based on SID chips. Anyone interested in midi controllers should check out the midibox project. I’m yet to build any of the devices but it has quite good doco and lots of synth/midi pron.


  5. sly says:


    listen… lots of sid music along with nes, game boy, sega, etc.

    definitely one on my playlist.

  6. Shadyman says:

    For an Atmega-emulated SID, see also: SwinSID: http://www.swinkels.tvtom.pl/swinsid/

  7. David Murray says:

    Am I the only one to ask the obvious question? Wouldn’t have been easier just to write the code directly on a Commodore 64? It would have sounded exactly the same and would have been a lot less work.

  8. VIPER! says:

    WOW that does take me back to the days of 8bit games and Midi on PC. They really worked hard to add music to computing back then. The ironic thing is this sounds “good” to me while my wife says shut that shit OFF!

  9. Daryl says:

    Why do I have a sudden urge to play Contra?

  10. VIPER! says:

    Continued…. What is that noise?!?
    (Me) Its a Sound Interface Device chip! From the Commodore 64.

    (Her) More like a Sound IN YOUR FACE Device!

  11. Simakuutio says:

    One nice resource for C64 music is still unmentioned here even it’s The Source: High Voltage Sid Collection (http://www.hvsc.c64.org). And yes, SID is far from Obsolete. Person who wrote this article, is obviously some young clueless wanna-be nerd who knows little to nothing about these things.

  12. damien says:

    I have about 4 or 5 of the 6581 SID chips laying around, leftover from the many C64s I used to own. Someday I *will* hook them all up. awesome chip.

  13. Pilotgeek says:

    “Long-dead systems”? Really? Tell that to the Commodore 64 and 1541 disk drive sitting on the desk in my room.

    “We have no idea where he picked up this obsolete chip” I know a guy who locally sells old computers from the 80’s and 90’s. I’ve never seen so many Apple II’s, Commodores, and TI 99’s. It’s not like computers just vaporize after faster ones come out…

  14. Teksprint says:

    Hurray for Thrashy. He is today a man.

  15. fsphil says:

    Good timing – I just got my C64 working again last night and I’ve been listening to a lot of SID music. It’s not too often I’m glad to see a blue screen ;-)


  16. lis0r says:

    Emulate it decently on an atmega? You’ll be lucky – PCs running at hundreds of MHz have trouble getting right, so there’s no way in hell a tiny microcontroller could make a passable job of it.

  17. AVR Micro says:

    Interesting idea! I miss those times.

  18. George says:

    Rob Hubbard, who composed a lot of classic game tunes, especially on the C64 (e.g. Monty on the Run, Commando, Delta, Skate or Die, Crazy Comets and many more), talks about the good old times.

  19. Rob says:

    SID’s aren’t available the way pig pancreases aren’t. Sure, you can’t have someone manufacture you either one — you start with the carcass and removed the desired component.

    Now I hope that no (working) C=64 was harmed for this project. Please.

    And as to comparing a dedicated microcontroller performing a single task to a softsynth running on a PC under an OS and with a GUI, etc., etc., my dear lis0r . . ., well, that’s exactly what we make uC’s and DSP’s for. Nothing wrong with emulating on a full PC for development or just for the convenience, it’s just not the most efficient way to do it. But we’ve all hammered a nail with a Crescent wrench in a pinch.

  20. Rob says:

    Hey George,

    Do you know that the occasion of Rob Hubbard’s talk was, and when? Additional info on YouTube for this series is a little scarce. I see that’s it’s part 1 of 5, but I’d kinda like to know what sort of conference you can hear lectures like that at.

    I’ll be listening to Crazy Comets if you need me.

  21. walt says:

    cool. but why use the 6581? the 8580r5 is the sid professional musicians are using.

  22. George says:

    Hey Rob,

    Sorry, I am not entirely sure. I think I googled him a while back when I heard an old C64 music track. I think it might have been “Assembly 03″ in Helsinki, Finland but cannot confirm.


  23. smrl says:


    i’ve experimented with these chips a bit. The 6581 and the 8580/6582 chips are markedly different, 6581 has a much higher noise floor, but it also has very different filtering characteristics. More gritty & warm. 8580 chips sound more digital/harsh/precise.

    Comes down to taste I suppose.

  24. r4v5 says:

    @lis0r: It’s not “emulating” the SID. The reason the SID is hard to emulate is that it basically is an NCO and a numerically controlled analog filter per voice. And each SID sounds slightly different, within the various revisions and versions they’ve done, because the technology for mixed analog/digital CMOS wasn’t fully there. The SID is a pretty amazing hack of a chip to begin with.

    But what the AVR is doing is decoding the MIDI stream and turning it into binary data for each voice to pump out *to* the SID.

  25. r4v5 says:

    Oh, I see the last comment now. Nevermind.

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