esp-open-rtos/extras/fast_i2c/i2c.c
2016-08-26 10:31:25 +02:00

161 lines
3.1 KiB
C

/*
* The MIT License (MIT)
*
* Copyright (c) 2015 Lilian Marazano (github.com/Zaltora)
* Based on Baoshi i2c library <mail(at)ba0sh1(dot)com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "i2c.h"
static uint8_t _scl_pin;
static uint8_t _sda_pin;
void i2c_init(uint8_t scl_pin, uint8_t sda_pin) {
_scl_pin = scl_pin ;
_sda_pin = sda_pin ;
gpio_enable(_sda_pin, GPIO_OUT_OPEN_DRAIN);
gpio_enable(_scl_pin, GPIO_OUT_OPEN_DRAIN);
// Set idle bus high
_SDA1;
_SCL1;
return;
}
uint8_t i2c_start(void) {
_SDA1;
_SCL1;
_DELAY;
if (_SDAX == 0) return false; // Bus busy
_SDA0;
_DELAY;
_SCL0;
return true;
}
void i2c_stop(void) {
_SDA0;
_SCL1;
_DELAY;
while (_SCLX == 0); // clock stretching
_SDA1;
_DELAY;
}
uint8_t i2c_write(uint8_t data) {
uint8_t ibit;
uint8_t ret;
for (ibit = 0; ibit < 8; ++ibit)
{
if (data & 0x80)
_SDA1;
else
_SDA0;
_DELAY;
_SCL1;
_DELAY;
data = data << 1;
_SCL0;
}
_SDA1;
_DELAY;
_SCL1;
_DELAY;
ret = (_SDAX == 0);
_SCL0;
_DELAY;
return ret;
}
uint8_t i2c_read(uint8_t ack) {
uint8_t data = 0;
uint8_t ibit = 8;
_SDA1;
while (ibit--)
{
data = data << 1;
_SCL0;
_DELAY;
_SCL1;
_DELAY;
if (_SDAX)
data = data | 0x01;
}
_SCL0;
if (ack)
_SDA0; // ACK
else
_SDA1; // NACK
_DELAY;
// Send clock
_SCL1;
_DELAY;
_SCL0;
_DELAY;
// ACK end
_SDA1;
return data;
}
bool i2c_slave_read(uint8_t slave_addr, uint8_t data, uint8_t *buf, uint16_t len) {
i2c_start();
if(!i2c_write(slave_addr<<1)) goto fail_send; // adress + W
if(!i2c_write(data)) goto fail_send; //Send byte
i2c_start(); // restart condition
if(!i2c_write((slave_addr<<1) | 1)) goto fail_send; // adress + R
while(--len) {
*(buf++) = i2c_read(1);
}
*buf = i2c_read(0);
i2c_stop();
return true;
fail_send:
i2c_stop();
return false ;
}
bool i2c_slave_write(uint8_t slave_addr, uint8_t *buf, uint16_t len) {
i2c_start();
if(!i2c_write(slave_addr<<1)) goto fail_send ; // adress + W
while (len--) {
if(!i2c_write((uint8_t) *(buf++))) goto fail_send ;
}
i2c_stop();
return true;
fail_send:
i2c_stop();
return false ;
}