There are 2 repositories under midi-interface topic.
UMK4x4 - 4-16 in/out and 3-15 IN/3OUT USB MIDI interface for STM32F103 series board
Standard MIDI Files (SMF) Processing Library
Control the Sega Mega Drive's Yamaha YM2612 and PSG with MIDI
STM32F103C8 (Blue Pill Board) as USB-Midi
harmonic table note layout, Euler Tonnetz, Browser GUI, WebMIDI Interface, Sequencer
mk2apc_4light adapts MIDI feedback messages from QLC+ to control button LEDs on the AKAI APC mini mk2 MIDI controller, providing a default mapping and allowing customization.
A MIDI interface for the Doepfer D3M keyboard