Ben Eater Tunes Up a SID Chip

The birth of high-quality computer audio did not happen with the release of the Sound Blaster 1.0 in 1989, as many people think. There were other chips that could blast out some righteous chiptunes years before that time. Perhaps the most famous sound chip of the early personal computing era is the 6581 Sound Interface Device, or SID. The SID chip powered the beeps and boops heard by a generation of Commodore 64 gamers, and it is still highly sought after today for its distinctive sound.

These chips might not quite be in the “rare” category yet, but they are getting harder to find by the year. And unfortunately, because of their desirability and diminishing availability, all sorts of fakes are popping up on secondary markets. If you are lucky enough to have a real SID chip in your collection, you will be happy to learn that it has finally been given the full Ben Eater treatment. In a recent video, he walks through the datasheet and shows how to wire it up to a 6502 processor, just the way it was intended to work.

As was the case with so many contemporary chips, the SID is a memory-mapped device. That means configuring it and playing sounds is as easy as storing and reading values in the system’s address space. The trick is knowing which addresses to use, and how to properly update each one to get the desired effect. And with a chip as complex as the SID, there is a lot to know. Eater breaks all of this down in his usual slow and careful way, so you can walk away knowing everything you need to know in half an hour.

Eater hooks the SID chip up to a custom 6502 breadboard computer that he previously made, but if you do not have one, the same basic techniques could even be used with a modern microcontroller or single-board computer. You just have to flip the right GPIO pins at the right time and get all the voltages right.

Even if you don’t have a SID chip sitting around, this video is still worth a watch. Make sure you stay for the end to see the demo. It’s chiptune heaven!