MPR121 Capacitive Touch Driver for esp-idf.
I ported from here.
ESP-IDF V5.0 or later.
ESP-IDF V4.4 release branch reached EOL in July 2024.
ESP-IDF V5.1 is required when using ESP32-C6.
Note for ESP-IDF V5.2.
A new i2c driver is now available in ESP-IDF V5.2.
Under ESP-IDF V5.2 or later, this project uses a new i2c driver.
MPR121 Capacitive Touch switch.
git clone https://github.com/nopnop2002/esp-idf-mpr121
cd esp-idf-mpr121
idf.py set-target {esp32/esp32s2/esp32s3/esp32c2/esp32c3/esp32c6}
idf.py menuconfig
idf.py flash
According to the MPR121 datasheet, the maximum i2c clock frequency is 400KHz.
The i2c clock frequency used by this project is 400KHz.
XTENSA's ESP32 has two i2c port: I2C_NUM_0/1.
You can use these two ports freely.
If you use this module at the same time as another I2C device using I2C port 0, you must change it to I2C port 1.
XTENSA's ESP32 has two i2c port: I2C_NUM_0/1.
I2C_NUM_0/1 are initialized independently, but legacy i2c drivers and new i2c drivers cannot be mixed.
If I2C_NUM_0 is initialized with the legacy i2c driver, I2C_NUM_1 must also be initialized with the legacy i2c driver.
If you use the MPR121 at the same time as other I2C devices that use legacy I2C drivers, the MPR121 must also be initialized with the legacy I2C driver.
Enabling this will use the legacy i2c driver even after ESP-IDF V5.2.
| MPR121 | ESP32 | ESP32-S2/S3 | ESP32-C2/C3/C6 | |
|---|---|---|---|---|
| SCL | -- | GPIO19 | GPIO12 | GPIO6 |
| SDA | -- | GPIO18 | GPIO11 | GPIO5 |
| IRQ | -- | GPIO15 | GPIO18 | GPIO4 |
| GND | -- | GND | GND | GND |
| VCC | -- | 3.3V | 3.3V | 3.3V |
Note
It is recommended to add external pull-up resistors for SDA/SCL pins to make the communication more stable, though the driver will enable internal pull-up resistors.
You can change it to any pin using menuconfig.
Supports multiple simultaneous touches.
I (55786) MAIN: electrode 0 was just touched
I (55786) MAIN: electrode 1 was just touched
I (55786) MAIN: electrode 2 was just touched
I (55786) MAIN: electrode 3 was just touched
I (58446) MAIN: electrode 0 was just released
I (58446) MAIN: electrode 1 was just released
I (58446) MAIN: electrode 2 was just released
I (58446) MAIN: electrode 3 was just released
Create idf_component.yml in the same directory as main.c.
YourProject --+-- CMakeLists.txt
+-- main --+-- main.c
+-- CMakeLists.txt
+-- idf_component.yml
Contents of idf_component.yml.
dependencies:
nopnop2002/mpr121:
path: components/mpr121
git: https://github.com/nopnop2002/esp-idf-mpr121.git
When you build a projects esp-idf will automaticly fetch repository to managed_components dir and link with your code.
YourProject --+-- CMakeLists.txt
+-- main --+-- main.c
| +-- CMakeLists.txt
| +-- idf_component.yml
+-- managed_components ----- nopnop2002__mpr121