I've been tinkering with CC65 to write a basic step-sequencer for my PET ... and have come up with this:

https://www.youtube.com/watch?v=1xyAVZnPNgo

The sequencer runs pretty smoothly on a real PET - but in the video I'm using the VICE emulator and the framerate is a bit glitchy.

Current functionality includes:

- randomize step values
- edit step values
- step forward/backward
- increase/decrease speed
- start/stop playback.

It outputs the step values using the PET built in piezo speaker but I plan on developing CV/Gate output using some kind of DAC hooked up to a parallel adapter.

I also need to sort out a more accurate timing routine and also implement different step modes such as REVERSE and BOUNCE.