esp-idf/examples/peripherals/i2c

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).