How the USB-MIDI2CV works


USB-MIDI2CV insideYou can buy the USB-MIDI2CV/plus prebuilt here:

The USB-MIDI2CV/plus

But how does it work?

Inside the interface is 4 resistors, 3 Capacitors, 4 Thonkiconn jacks and a 32U4 Pro Micro.

The 32U4 is programmed with moco LUFA, firmware that makes the Pro Micro behave like a USB-HID compliant MIDI interface.


The Timers of the 32U4 are run as PWM-DAC’s to generate the control voltages.
And the resistors and caps are used to smooth the voltage out.

Key on/off events on channel 1 is converted into a 1 volt/octave pitch CV and on channel 2 as a Hertz/volt CV.

The key on/off Gate signal is output as a 0/5 volt CV.
If it’s on MIDI channel 2 it is output as S-trig instead (open-collector ground).

MIDI-CC’s #01 and #07 are output as the CV1 and CV2 voltages.

If anything is received on MIDI channel 10 all outputs switch to Gate mode and are used as drum-triggers.

Simple but effective.




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