History

Sakari Kapanen 4a1b600be4 i2c: improve timing Look-up tables were used for determining the delay loop counts before. Based on these hand-tuned values, the loop overhead was estimated for each option -- 80 and 160 MHz, fast and slow GPIO access. Instead of the great number of tunable parameters one now only has to tune the overhead values if the code is changed. Functions were added to the API which allow setting an arbitrary frequency. API backward compatibility is retained. i2c: fix potential overflow situation		2018-02-27 23:47:16 +02:00
..
component.mk	Rework component makefiles to have a default <component>_ROOT	2015-09-08 09:59:59 +10:00
i2c.c	i2c: improve timing	2018-02-27 23:47:16 +02:00
i2c.h	i2c: improve timing	2018-02-27 23:47:16 +02:00
LICENSE	Added BMP180 and I2C driver and example	2015-08-31 13:39:27 +02:00
README.md	I2C code formatting, README fix (#462 )	2017-10-12 17:42:34 +05:00

README.md

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].

Basic usage

#include <i2c.h>

#define BUS     (0)
#define SCL_PIN (0)
#define SDA_PIN (2)

uint8_t slave_addr = 0x20;
uint8_t reg_addr = 0x1f;
uint8_t reg_data;

i2c_init(BUS, SCL_PIN, SDA_PIN, I2C_FREQ_400K);

// Write 1 byte to slave register
int err = i2c_slave_write(BUS, slave_addr, &reg_addr, &data, 1);
if (err != 0)
{
	// do something with error
}

// Issue write to slave, sending reg_addr, followed by reading 1 byte
err = i2c_slave_read(BUS, slave_addr, &reg_addr, &reg_data, 1);

For details please see extras/i2c/i2c.h.

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