Firmware

Note to reader: a lot of this firmware has been developed in 45-minute time increment after a day's work, which in part explains that the code quality is not great. Refactoring and making the code cleaner will be a future focus.

If you are an experimented C/C++ dev, and you whish to help on this project, I might be able to send you pre-production sample of the minichord in exchange for a bit of help. Don't hesitate to reach out to minichord@benjaminpoilve.com .

Structure

This folder contains a PlatformIO project for Teensy 4.0.

In particular the it contains :

• the srcfolder containing the main.cpp file, as well as the file defining the USB name of the device, name.c
• the lib folder containing the librairies for the chips used, the debouncing and the potentiometer logic
• the include folder containing all the Teensy audio architecture definition, as well as the hardware definitions and the sysex_handler.hfile.

The next interesting folder is related to the "generator". To be able to simply modify parameters related to sound synthesis and have a coherent firmware and control software, those parameters are defined in a parameters.json file. By using the generation script, both the interface and necessary firmware file are generated. Note that the interface will be included in the minichord website by using the build_site.sh script in the documentation folder.

The resulting fimware itself is present at the root of the project : firmware.hex.

Usage

If you want to set-up a PlatformIO environnement for Teensy, please follow the tutorial for PlatformIO Teensy usage available here

Once the project is set-up, you can modify, compile and upload the code directly from VSCode.

To use the generator, set-up a venv in the generator directory using python3 -m venv .venv. Then enter the venv by using source venv/bin/activate.

Once in the venv, install the necessary packages by using pip3 install -r requirements.txt.

Generation can then simply be done by running the generate.pyscript: python3 generate.py.

Caveat

To get the midi interface to display the right number of cables, the usb_desc.h file in the ~/.platformio/packages/framework-arduinoteensy/cores/teensy4 folder needs to be modified to the following:

#elif defined(USB_MIDI16_AUDIO_SERIAL)
  #define VENDOR_ID		0x16C0
  #define PRODUCT_ID		0x048A
  #define BCD_DEVICE		0x0212
  #define MANUFACTURER_NAME	{'m','i','n','i','c','h','o','r','d'}
  #define MANUFACTURER_NAME_LEN	9
  #define PRODUCT_NAME		{'m','i','n','i','c','h','o','r','d'}
  #define PRODUCT_NAME_LEN	9
  #define EP0_SIZE		64
  #define NUM_ENDPOINTS         8
  #define NUM_INTERFACE		6
  #define CDC_IAD_DESCRIPTOR	1
  #define CDC_STATUS_INTERFACE	0
  #define CDC_DATA_INTERFACE	1	// Serial
  #define CDC_ACM_ENDPOINT	2
  #define CDC_RX_ENDPOINT       3
  #define CDC_TX_ENDPOINT       3
  #define CDC_ACM_SIZE          16
  #define CDC_RX_SIZE_480       512
  #define CDC_TX_SIZE_480       512
  #define CDC_RX_SIZE_12        64
  #define CDC_TX_SIZE_12        64
  #define MIDI_INTERFACE        2	// MIDI
  #define MIDI_NUM_CABLES       2
  #define MIDI_TX_ENDPOINT      4
  #define MIDI_TX_SIZE_12       64
  #define MIDI_TX_SIZE_480      512
  #define MIDI_RX_ENDPOINT      4
  #define MIDI_RX_SIZE_12       64
  #define MIDI_RX_SIZE_480      512
  #define AUDIO_INTERFACE	3	// Audio (uses 3 consecutive interfaces)
  #define AUDIO_TX_ENDPOINT     5
  #define AUDIO_TX_SIZE         180
  #define AUDIO_RX_ENDPOINT     5
  #define AUDIO_RX_SIZE         180
  #define AUDIO_SYNC_ENDPOINT	6
  #define ENDPOINT2_CONFIG	ENDPOINT_RECEIVE_UNUSED + ENDPOINT_TRANSMIT_INTERRUPT
  #define ENDPOINT3_CONFIG	ENDPOINT_RECEIVE_BULK + ENDPOINT_TRANSMIT_BULK
  #define ENDPOINT4_CONFIG	ENDPOINT_RECEIVE_BULK + ENDPOINT_TRANSMIT_BULK
  #define ENDPOINT5_CONFIG	ENDPOINT_RECEIVE_ISOCHRONOUS + ENDPOINT_TRANSMIT_ISOCHRONOUS
  #define ENDPOINT6_CONFIG	ENDPOINT_RECEIVE_UNUSED + ENDPOINT_TRANSMIT_ISOCHRONOUS