[chipweinberger]

Very custom. By now there is are good USB-MIDI examples and Espressif USB support has come a long way in the past couple years.

modern ESP-IDF: https://github.com/espressif/esp-idf/pull/12566

versus 3 years ago: https://github.com/chipweinberger/xesp-usbh

[odiroot]

Nice, thanks for the links :)