bluepill-midi USB-MIDI interface with three midi ports. (c) 2019, GNU GPL v3. Built on STM32F103C8 (Blue Pill Board). Compiling: git clone make make flash connect UARTs to MIDI optocouplers Hardware schematics: https://learn.sparkfun.com/tutorials/midi-tutorial/hardware--electronic-implementation https://www.midi.org/specifications/midi-transports-specifications/5-pin-din-electrical-specs
