I built up the first-revision shim control board (SCB) last night, and in a rush to unit-test each functional subcircuit, I managed to apply 5V (without current limiting) to the input of my LDO-enable optocoupler, bricking the chip and limiting what I could do over the weekend with the SCB... oops!

If anybody's wondering why I've made a second board for a project that boasts a single board solution, don't fret! The final PyPPM hardware design will re-integrate the PPM and SCB boards onto a single PCB. I'm really excited to start work on the next board design; it'll definitely be a nice challenge!