I’ve been soldering up the drum sequencer’s interface board this evening. This board contains all of the back-panel ports: power, the power switch, and MIDI in/out/thru. It consolidates these into the four lines Vcc, GND, TX, and RX, which will drive the microcontroller. This happens to be the same set of lines coming out of the FTDI USB interface; the idea is that I can plug the microcontroller into either the interface board or the USB connector, and it will behave the same way in either case. This should make life easier when debugging the front panel.

The power supply is a simple LM7805-based circuit.