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esp-idf/examples/18_i2c
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Wangjialin 9c7cc86793 1. modify i2c_set_pin function 
2. update example comments and other minor changes
3. rename API:  i2c_cmd_link_create/i2c_cmd_link_delete (+4 squashed commits)

Squashed commits:
[2e0ac3e] 1. coding style: add one space after condition key words.
2. modify i2c.h, use gpio_num_t instead of int, improve comments of return values
3. add i2c index in index.rst
4. add readme for i2c example
[4991d92] update i2c.doc
[88b672e] driver: i2c

1. add mux and spin lock to run in a thread-safe way.
2. modify example code
[4eb15fe] driver: i2c code

1. add i2c master code
2. add i2c slave code
3. add i2c example code
4. add DRAM_ATTR for I2C array
2017-01-03 00:57:19 +08:00
..
main 1. modify i2c_set_pin function 2017-01-03 00:57:19 +08:00
Makefile 1. modify i2c_set_pin function 2017-01-03 00:57:19 +08:00
README.md 1. modify i2c_set_pin function 2017-01-03 00:57:19 +08:00

README.md

I2C Example

  • This example will show you how to use I2C module by running two tasks on i2c bus:

    • read external i2c sensor, here we use a BH1750 light sensor(GY-30 module) for instance.
    • Use one I2C port(master mode) to read or write the other I2C port(slave mode) on one ESP32 chip.

  • Pin assignment:

    • slave :
      • GPIO25 is assigned as the data signal of i2c slave port
      • GPIO26 is assigned as the clock signal of i2c slave port
    • master:
      • GPIO18 is assigned as the data signal of i2c master port
      • GPIO19 is assigned as the clock signal of i2c master port

  • Connection:

    • connect GPIO18 with GPIO25
    • connect GPIO19 with GPIO26
    • connect sda/scl of sensor with GPIO18/GPIO19
    • no need to add external pull-up resistors, driver will enable internal pull-up resistors.

  • Test items:

    • read the sensor data, if connected.
    • i2c master(ESP32) will write data to i2c slave(ESP32).
    • i2c master(ESP32) will read data from i2c slave(ESP32).