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108 lines
3.9 KiB
Markdown
108 lines
3.9 KiB
Markdown
# esp-idf-mpr121
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MPR121 Capacitive Touch Driver for esp-idf.
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I ported from [here](https://github.com/BareConductive/mpr121).
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# Software requirements
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ESP-IDF V5.0 or later.
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ESP-IDF V4.4 release branch reached EOL in July 2024.
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ESP-IDF V5.1 is required when using ESP32-C6.
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__Note for ESP-IDF V5.2.__
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A new i2c driver is now available in ESP-IDF V5.2.
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Under ESP-IDF V5.2 or later, this project uses a new i2c driver.
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# Hardware requirements
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MPR121 Capacitive Touch switch.
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# Installation
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```Shell
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git clone https://github.com/nopnop2002/esp-idf-mpr121
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cd esp-idf-mpr121
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idf.py set-target {esp32/esp32s2/esp32s3/esp32c2/esp32c3/esp32c6}
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idf.py menuconfig
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idf.py flash
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```
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# Configuration
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# I2C Clock speed
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According to the MPR121 datasheet, the maximum i2c clock frequency is 400KHz.
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The i2c clock frequency used by this project is 400KHz.
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# I2C Port selection
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XTENSA's ESP32 has two i2c port: I2C_NUM_0/1.
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You can use these two ports freely.
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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.
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# Force legacy i2c driver
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XTENSA's ESP32 has two i2c port: I2C_NUM_0/1.
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I2C_NUM_0/1 are initialized independently, but legacy i2c drivers and new i2c drivers cannot be mixed.
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If I2C_NUM_0 is initialized with the legacy i2c driver, I2C_NUM_1 must also be initialized with the legacy i2c driver.
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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.
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Enabling this will use the legacy i2c driver even after ESP-IDF V5.2.
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# Wiring
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|MPR121||ESP32|ESP32-S2/S3|ESP32-C2/C3/C6|
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|:-:|:-:|:-:|:-:|:-:|
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|SCL|--|GPIO19|GPIO12|GPIO6|
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|SDA|--|GPIO18|GPIO11|GPIO5|
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|IRQ|--|GPIO15|GPIO18|GPIO4|
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|GND|--|GND|GND|GND|
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|VCC|--|3.3V|3.3V|3.3V|
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__Note__
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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.
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__You can change it to any pin using menuconfig.__
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# Screen Shot
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Supports multiple simultaneous touches.
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```
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I (55786) MAIN: electrode 0 was just touched
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I (55786) MAIN: electrode 1 was just touched
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I (55786) MAIN: electrode 2 was just touched
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I (55786) MAIN: electrode 3 was just touched
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I (58446) MAIN: electrode 0 was just released
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I (58446) MAIN: electrode 1 was just released
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I (58446) MAIN: electrode 2 was just released
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I (58446) MAIN: electrode 3 was just released
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```
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# How to use this component in your project
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Create idf_component.yml in the same directory as main.c.
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```
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YourProject --+-- CMakeLists.txt
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+-- main --+-- main.c
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+-- CMakeLists.txt
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+-- idf_component.yml
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```
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Contents of idf_component.yml.
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```
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dependencies:
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nopnop2002/mpr121:
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path: components/mpr121
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git: https://github.com/nopnop2002/esp-idf-mpr121.git
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```
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When you build a projects esp-idf will automaticly fetch repository to managed_components dir and link with your code.
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```
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YourProject --+-- CMakeLists.txt
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+-- main --+-- main.c
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| +-- idf_component.yml
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+-- managed_components ----- nopnop2002__mpr121
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```
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# Reference
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https://github.com/nopnop2002/esp-idf-ttp229
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