MIDI Project with libopencm3

This project implements a USB MIDI controller using the STM32F103C8T6 “Blue Pill” board and libopencm3 midi usb Examples.

It uses a TTP229 16-key capacitive touch keypad as the input source and sends MIDI messages over USB.

Hardware Setup

Hardware Needed

1. MCU Board: STM32F103C8T6 ("Blue Pill")
2. Input Sensor: TTP229 16-key touch sensor (I²C mode)

Wiring

TTP229 Pin	STM32F103C8 Pin
SDO	PA6
SCL	PA7
TP2	Connected
TP3	Connected
TP4	Connected
VCC/GND	3.3V / GND

The TP2, TP3, and TP4 pins on the TTP229 side are connected to configure the sensor for 16-key mode and multitouch function.

Getting Started

Prerequisites

Make sure you have the following toolchain

sudo apt install stlink-tools gcc-arm-none-eabi

Clone the repo

git clone --recurse-submodules https://github.com/arbipink/midi-project-with-ttp229-and-stm32-using-libopencm3.git midi-project

Build

first build libopencm3 (only needed once)

cd midi-project
make -C libopencm3

then build the project

make -C my-project

Flash

cd my-project
st-flash --reset write midi-project.bin 0x8000000

What i will do in the future

1. Add functionality to change octave
2. Add functionality to control midi cc
3. Change from polling driven to interrupt driven for the keys

License

• This project’s source code: MIT License
• libopencm3 dependency: LGPL v3.0 or later