esp-open-rtos/extras/i2c/README.md

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# Yet another I2C driver for the ESP8266
This time a driver for the excellent esp-open-rtos. This is a bit banging I2C driver based on the Wikipedia pesudo C code [1].
### Adding to your project
Add the driver to your project as a submodule rather than cloning it:
````
% git submodule add https://github.com/kanflo/esp-open-rtos-driver-i2c.git i2c
````
The esp-open-rtos makefile-fu will make sure the driver is built.
### Usage
````
#include <i2c.h>
#define SCL_PIN (0)
#define SDA_PIN (2)
uint8_t slave_addr = 0x20;
uint8_t reg_addr = 0x1f;
uint8_t reg_data;
uint8_t data[] = {reg_addr, 0xc8};
i2c_init(SCL_PIN, SDA_PIN);
// Write data to slave
bool success = i2c_slave_write(slave_addr, data, sizeof(data));
// Issue write to slave, sending reg_addr, followed by reading 1 byte
success = i2c_slave_read(slave_addr, &reg_addr, reg_data, 1);
````
The driver is released under the MIT license.
[1] https://en.wikipedia.org/wiki/I²C#Example_of_bit-banging_the_I.C2.B2C_Master_protocol