/*********************************************************************************
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* Copyright: (C) 2014 Guo Wenxue<guowenxue@gmail.com>
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* All rights reserved.
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*
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* Filename: gpio_i2c.c
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* Description: STM8 GPIOÄ£ÄâI2C´úÂë
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*
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* Version: 1.0.0(09/28/2014)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "09/28/2014 10:58:17 PM"
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*
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********************************************************************************/
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#include "gpio_i2c.h"
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#include "timing_delay.h"
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/* ¿ªÊ¼ÐźţºSCLΪ¸ßµçƽʱ£¬SDAÓɸߵçƽÏòµÍµçƽÌø±ä£¬¿ªÊ¼´«ËÍÊý¾Ý. */
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void gpio_i2c_start(void)
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{
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SDA_MODE_OUT;
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SCL_LOW;
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TIMDelay_N10us(1);
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SDA_HIGH;
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TIMDelay_N10us(1);
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SCL_HIGH;
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TIMDelay_N10us(1);
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SDA_LOW;
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TIMDelay_N10us(1);
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SCL_LOW; /* StartÖ®ºóBUS×ÜÏßÒ»°ã±»ÈÏΪ´¦ÓÚÕ¼Ïß״̬ */
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TIMDelay_N10us(1);
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}
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/* ½áÊøÐźţºSCLΪ¸ßµçƽʱ£¬SDAÓɵ͵çƽÏò¸ßµçƽÌø±ä£¬½áÊø´«ËÍÊý¾Ý. */
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void gpio_i2c_stop(void)
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{
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SDA_MODE_OUT;
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SCL_LOW;
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TIMDelay_N10us(1);
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SDA_LOW;
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TIMDelay_N10us(1);
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SCL_HIGH;
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TIMDelay_N10us(1);
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SDA_HIGH;
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TIMDelay_N10us(1);
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}
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/* ¶ÔÓÚ·´À¡ÓÐЧӦ´ðλACKµÄÒªÇóÊÇ£¬½ÓÊÕÆ÷ÔÚµÚ9¸öʱÖÓÂö³å֮ǰµÄ
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*µÍµçƽÆڼ佫SDAÏßÀµÍ£¬²¢ÇÒÈ·±£ÔÚ¸ÃʱÖӵĸߵçƽÆÚ¼äΪÎȶ¨µÄµÍµçƽ
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*/
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void gpio_i2c_send_ack(void)
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{
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SDA_MODE_OUT;
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/* ĬÈÏSCLÊǵ͵çƽ£¬ÏÖÔڸıäÊý¾Ý£¬µÍµçƽ±íʾACK */
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SDA_LOW;
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TIMDelay_N10us(1);
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/* ʱÖÓÏßÀ¸ß²¢Î¬³ÖSDA״̬ */
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SCL_HIGH;
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TIMDelay_N10us(1);
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/* »Ö¸´Ê±ÖÓÏßΪµÍµçƽ£¬×ÜÏßæ */
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SCL_LOW;
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TIMDelay_N10us(1);
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}
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/* NACK(°ÑÊý¾Ý×ÜÏߵĵçƽÀµÍ¸ß)À´±íʾÊý¾Ý³É¹¦Ê§°Ü */
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void gpio_i2c_send_nak(void)
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{
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SDA_MODE_OUT;
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/* ĬÈÏSCLÊǵ͵çƽ£¬ÏÖÔڸıäÊý¾Ý£¬¸ßµçƽ±íʾNAK */
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SDA_HIGH;
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TIMDelay_N10us(1);
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/* ʱÖÓÏßÀ¸ß²¢Î¬³ÖSDA״̬ */
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SCL_HIGH;
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TIMDelay_N10us(1);
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/* »Ö¸´Ê±ÖÓÏßΪµÍµçƽ£¬×ÜÏßæ */
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SCL_LOW;
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TIMDelay_N10us(1);
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}
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/* I2C ×ÜÏ߶ÁÒ»¸öACKÐźÅ
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* ·µ»ØÖµ:0 ÊÕµ½ACK 1: ÊÕµ½NAK
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*/
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uint8_t gpio_i2c_wait_ack(void)
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{
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uint8_t rv;
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uint8_t times = 200;
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SDA_MODE_IN;
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/* ʱÖÓÏßÀ¸ß */
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SCL_HIGH;
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TIMDelay_N10us(1);
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do
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{
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times --;
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} while ( (SDA_DAT==1) && (times!=0) );
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if( !times )
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{
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/* µÈ´ý ACK ³¬Ê±£¬½ÓÊÕµ½NAK */
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rv = I2C_NAK;
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goto OUT;
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}
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/* µÈµ½ACK */
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SCL_LOW;
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TIMDelay_N10us(1);
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rv = I2C_ACK;
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OUT:
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return rv;
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}
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/* I2C×ÜÏß·¢ËÍÒ»¸ö×Ö½ÚÊý¾Ý:
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* ·µ»ØÖµ:0 ·¢Ëͳɹ¦£¬µÈµ½ACK 1: ·¢ËÍʧ°Ü,ÊÕµ½NAK
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*/
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uint8_t gpio_i2c_write_byte(uint8_t byte)
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{
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int i;
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uint8_t rv = I2C_ACK;
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SDA_MODE_OUT;
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/* SCLΪµÍµçƽʱ,SDAÏß²ÅÄܸı䴫ÊäµÄbit; SCLΪ¸ßµçƽʱ,SDAÏß±£³ÖÎȶ¨ */
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for(i=7; i>=0; i--) /* MSB */
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{
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/*MSB: Êä³öÏàӦλµÄµçƽÐźŠ*/
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if( byte&(1<<i) )
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SDA_HIGH;
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else
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SDA_LOW;
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TIMDelay_N10us(1);
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SCL_HIGH;
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TIMDelay_N10us(1);
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SCL_LOW;
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TIMDelay_N10us(1);
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}
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rv = gpio_i2c_wait_ack();
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return rv;
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}
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/* I2C×ÜÏß½ÓÊÕÒ»¸ö×Ö½ÚÊý¾Ý */
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uint8_t gpio_i2c_read_byte(void)
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{
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uint8_t bit;
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uint8_t byte = 0;
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SDA_MODE_IN;
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for(bit=0; bit<8; bit++)
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{
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byte <<= 1;
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SCL_HIGH;
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TIMDelay_N10us(2);
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if(SDA_DAT)
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byte |= 1;
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SCL_LOW;
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TIMDelay_N10us(2);
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}
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gpio_i2c_send_ack();
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return byte;
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}
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uint8_t gpio_i2c_read(uint8_t addr, uint8_t reg_addr)
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{
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int rv;
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uint8_t data = 0;
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// Start condition
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gpio_i2c_start();
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// Send the slave address with write bit and check for ACK
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if (I2C_ACK != gpio_i2c_write_byte(addr | I2C_DIR_WRITE))
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{
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rv = I2C_ERROR;
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goto OUT;
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}
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// Send the register address and check for ACK
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if (I2C_ACK != gpio_i2c_write_byte(reg_addr))
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{
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rv = I2C_ERROR;
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goto OUT;
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}
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// Repeated start condition
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gpio_i2c_start();
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// Send the slave address with read bit and check for ACK
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if (I2C_ACK != gpio_i2c_write_byte(addr | I2C_DIR_READ))
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{
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rv = I2C_ERROR;
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goto OUT;
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}
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// Read the data byte
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data = gpio_i2c_read_byte();
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rv = data;
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OUT:
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gpio_i2c_stop();
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if (rv == I2C_ERROR)
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{
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return -1;
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}
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return rv;
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}
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int gpio_i2c_write(uint8_t addr, uint8_t reg_addr, uint8_t data)
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{
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int rv = I2C_OK;
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gpio_i2c_start();
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// Send the slave device address with the write bit and check for ACK
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if (I2C_ACK != gpio_i2c_write_byte(addr | I2C_DIR_WRITE))
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{
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rv = I2C_ERROR;
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goto OUT;
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}
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// Send the register address and check for ACK
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if (I2C_ACK != gpio_i2c_write_byte(reg_addr))
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{
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rv = I2C_ERROR;
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goto OUT;
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}
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// Send the data byte and check for ACK
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if (I2C_ACK != gpio_i2c_write_byte(data))
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{
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rv = I2C_ERROR;
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}
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OUT:
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gpio_i2c_stop();
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return rv;
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}
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