MIDI2CV

just some musing on a midi to cv (control voltage) converter for eurorack.

this is the code for the second revision. which uses usb midi!

there's 4 mcp4728 DACs that provide 16 channels of control voltages (0-5v). 8 of those are for notes, the other 8 are for note velocities, and the other 8 are gates (the gates and leds are controlled via a 74HC595 shift register). there's a usb midi interface which uses adafruit's rp2040 with usb host board. the EZ_USB_MIDI_HOST handles usb midi and uses the sekigon-gonnoc/Pico-PIO-USB library (programmable input/output) as a bit-bangin' software usb host controller.

IMPORTANT NOTE: i ended up using v0.5.3 of this library because the newest version (v0.6.0 at the time of writing this) was very unstable read more in this github issue.

i also ran into another dead end where my rp2040 would crash when sending i2c data to more than one mcp4728 DAC so i used another rp2040 (a kb2040, that adafruit sent me as a freebie) to do the i2c communication with the DACs and use serial UART between the two rp2040s.

so please note:

1. midi2 is the arduino sketch for the rp2040 with usb host
2. 2cv is the arduino sketch for the kb2040

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made with 🖤 in NYC