John Slee writes:
Anyway, I decided to try to make my own clock divider. Didn’t take long to get something working, and you can see the results in the video above. The genuine Arduino Uno is generating a simple square wave on pin 13, which you can observe with the built-in LED. The Freetronics clone is triggering on the rising edge of the square wave and operating a clock divider with /1 through /8 outputs. The /1 through /4 divider outputs are attached to a little test-LED board I made a while back. You can see that it has a bug caused by my forgetting to reset the tick counter.
To actually use this in a modular synth it would need to tolerate inputs in the range -12V to +12V, maybe via a bunch of MOSFETs. It might be easier to just ditch the AVR and use flip-flops