Midi Controller Using Micropython on ESP32 DevKit board

Tools

Useful Links

https://docs.micropython.org/en/latest/esp32/quickref.html https://www.digikey.ca/en/maker/projects/micropython-basics-load-files-run-code/fb1fcedaf11e4547943abfdd8ad825ce

Local Virtualenv

Poetry

(--no-root do not install the source code, but only the dependencies)

poetry install --no-root

PyEnv Virtualenv (Deprecated)

Using pyenv-virtualenv micropython: pyenv virtualenv activate micropython

pip install -r requirements.txt

External Libraries

In libs directory, clone the following repos:

• git@github.com:miguelgrinberg/microdot.git
• git@github.com:adafruit/Adafruit_CircuitPython_MIDI.git

They will be added to the frozen part of the custom firmware.

Flash firmware

Erase and flash on ESP32 (option to erase at the same time is not working) WARNING: Using more recent firmware (or custom) is not working yet

esptool.py --port /dev/tty.usbserial-0001 erase_flash
esptool.py --port /dev/tty.usbserial-0001 --chip esp32 --baud 460800 write_flash -z 0x1000 firmware/esp32-20210902-v1.20.0.bin

Flash only the micropython firmware (keep boot and data) Example using OTA firmware in ota_0 partition

esptool.py --port /dev/tty.usbserial-0001 --chip esp32 --baud 460800 write_flash -z 0x10000 build/GENERIC_OTA/micropython.bin

Build Firmware

Building in docker image:

docker build -f firmware/Dockerfile -t midigoat .
docker run --rm -ti --volume $PWD/firmware:/root/export midigoat /bin/bash -c "cp /micropython/ports/esp32/build-GENERIC/firmware.bin /root/export/esp32-generic-midigoat.bin"

Copy build directory locally

docker run --rm -ti --volume $PWD/build:/root/export midigoat /bin/bash -c "cp -R /micropython/ports/esp32/build-GENERIC_OTA /root/export/GENERIC_OTA"

Firmware is located in the image at /micropython/ports/esp32/build-GENERIC/firmware.bin

Test live

ampy --port /dev/tty.usbserial-0001 run src/main.py

Upload file

Don't forget to remove pyc files!

find . | grep -E "(__pycache__|\.pyc|\.pyo$)" | xargs rm -rf

ampy --port /dev/tty.usbserial-0001 put src/wifi.py /wifi.py
ampy --port /dev/tty.usbserial-0001 put src/midicontroller /midicontroller
ampy --port /dev/tty.usbserial-0001 put banks_dir /banks_dir
ampy --port /dev/tty.usbserial-0001 put src/main.py /main.py

or from the rshell

rsync data/presets /pyboard/presets
mkdir /pyboard/banks
rsync data/banks_existenza/00.Generic /pyboard/banks/generic
rsync data/banks_existenza/00.Generic /pyboard/banks/generic
rsync data/banks_existenza /pyboard/banks
rsync src/midicontroller /pyboard/midicontroller
cp src/wifi.py /pyboard/
cp src/main.py /pyboard/

Connect to REPL

Using screen

screen /dev/tty.usbserial-0001 115200

exit with Ctrl-A; Ctrl-\

Using rshell

rshell -p /dev/tty.usbserial-0001

exit with Ctrl-D

from rshell

repl

exit with Ctrl-X

Using mpremote with aiorepl

mpremote connect /dev/tty.usbserial-0001

Then start aiorepl prompt (Long press button 4)

Free Flash Space

From REPL

import uos
fs_stat = uos.statvfs('/')
fs_size = fs_stat[0] * fs_stat[2]
fs_free = fs_stat[0] * fs_stat[3]
print("File System Size {:,} - Free Space {:,}".format(fs_size, fs_free))

Wiring Schema

R-Tx = 10 Ohm

R-V3.3 = 47 Ohm

Note: Connect 74HC165 to Pin D3 (GPIO0) make the board fail to boot.

External Libraries Used

https://github.com/adafruit/Adafruit_CircuitPython_MIDI

• added __str__ to MIDIMessage, ProgramChange and ControlChange classes

https://github.com/dhylands/python_lcd

Ideas

Long press open a setup menu:

1. Connect Home Wifi
2. Create own Wifi
3. Start/Stop Web Server
4. Start/Stop Bluetooth
5. Start REPL (AsyncIO)
6. Quit setup menu

TODO

• Create manifest files for frozen code: https://docs.micropython.org/en/latest/reference/manifest.html#high-level-functions
• Implement OTA firmware update:
  • https://docs.micropython.org/en/latest/library/esp32.html
  • https://github.com/orgs/micropython/discussions/9579
  • https://iot49.org/projects/internet/ota.html
• Freeze static files:
  • https://github.com/peterhinch/micropython_data_to_py
  • https://github.com/insighio/microfreezer