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