ER-USB-MIDI

Features

• MIDI/Serial interface
  • Out/In
  • Based on Adafruit QT Py RP2040 USB to Serial MIDI Friends design
• USB MIDI to MIDI Serial
• MIDI Serial to USB MIDI
• Built on ER-PROTO-02
• XAIO RP2040 CPU
• MIDI over TRS A type connector
• J5 = MIDI Serial input
• J6 = MIDI Serial output

Resources

• A simplified guide to TRS MIDI

Seeeduino XIAO RP2040

There are 14 GPIO PINs on XIAO RP2040, on which there are 11 digital pins, 4 analog pins, 11 PWM Pins,1 I2C interface, 1 UART interface, 1 SPI interface, 1 SWD Bonding pad interface.

• Seeed XIAO RP2040 product page
• Seeed XIAO RP2040 wiki page

Design

XAIO RP2040 CPU

MIDI Jacks

• J5, J6 = PJ366ST
• Install both Pot/Jack headers/sockets
  • Female sockets on Controls card
  • Male Pins on Daughtercard

MIDI In

• 3.3V MIDI serial out to Arduino Pro Mini
  • R6 = 680
  • R7 = 1.2K

Daughtercard Prototyping Area

Build

• Daughtercard/Controls card

• Cap on MIDI In GND pin

Software

• Adafruit MIDI Friends
  • Bridges USB MIDI to Serial MIDI
    • Takes in MIDI from the USB (typically from a PC running a MIDI player) and send out MIDI
    • Maintains optical isolation on MIDI
• Adafruit MIDI API
• Listens to MIDI Channel 1
• Load CircuitPython to card (using v7.x)
  • Press right button then insert USB cable
  • Drive will appear on PC
  • Drop CircuitPython uf2 onto the drive
• Drop application and libraries onto card - Drop as code.py to auto-run
• Download/run MIDIEditor
  • Edit
  • Settings
  • MIDI Output
    • Select CircuitPython Audio
  • Load MIDI file (Free MIDI files sites)
  • Click play button