The emUSB-Host MIDI class enables the communication with any device that supports the MIDI protocol via USB as specified by the USB Implementers Forum.
The USB class protocol for MIDI was defined for mapping the MIDI protocol to USB, so that music playing and controlling devices can interact via USB. These music devices can be of any kind using the MIDI interface via USB, whether MIDI controllers, MIDI sequencers, drum computers, instruments, effect units, samplers, or synthesizers.
SEGGER provides multiple examples with the MIDI class for emUSB-Host. One of the examples is playing a MIDI sequence through a connected MIDI synthesizer and displays, in real time, piano notes and accompanying lyrics on the display of an STM32F746G-DISCO board.
Another example converts a standard PC keyboard into a MIDI controller by applying the HID and MIDI classses. The MIDI controller is capable of controlling a synthesizer or other sound generating devices by sending commands via the MIDI interface on each keystroke.