Mini-I/O 16

This is a small board with 16 LEDs and pairs of switches for exercising digital circuits. It can draw power from the circuit under test, or it can use USB-C. It's intended to run at 5V, but the high-level threshold for AHCT logic (the LEDs are buffered by two 74AHCT240s) is wide enough that it might work at 3.3V as well.

v2.0 replaces the SMD headers with through-hole headers, as the SMD headers tended to break off easily.