/**********************************************************************
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* Copyright: (C)2021 LingYun IoT System Studio <www.weike-iot.com>
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* Author: GuoWenxue<guowenxue@gmail.com> QQ: 281143292
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* Description: BearKE1 NB-IoT Board GPIO simulate I2C bus source code
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*
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* Notice: Must implement delay_us() by timer in tim.h first.
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*
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* ChangeLog:
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* Version Date Author Description
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* V1.0.0 2021.08.10 GuoWenxue Release initial version
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***********************************************************************/
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#include <stdio.h>
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#include "stm32l4xx_hal.h"
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#include "tim.h" /* delay_us() implement */
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#include "gpio.h"
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#include "gpio_i2c.h"
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/* comment follow macro will disable I2C bus clock stretching support
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* reference: http://www.i2c-bus.org/clock-stretching/
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*/
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#define I2C_CLK_STRETCH_TIMEOUT 50
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/* uncomment follow macro will enable debug print */
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//#define CONFIG_GPIO_I2C_DEBUG
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#ifdef CONFIG_GPIO_I2C_DEBUG
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#define i2c_print(format,args...) printf(format, ##args)
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#else
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#define i2c_print(format,args...) do{} while(0)
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#endif
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/* GPIO Simulate I2C Bus pins */
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typedef struct i2c_gpio_s
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{
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GPIO_TypeDef *group;
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uint16_t scl; /* SCL */
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uint16_t sda; /* SDA */
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} i2c_gpio_t;
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static i2c_gpio_t i2c_pins = { GPIOB, GPIO_PIN_13/*SCL*/, GPIO_PIN_14/*SDA*/ };
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#define SDA_IN() do{ GPIO_InitTypeDef GPIO_InitStruct = {0}; \
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GPIO_InitStruct.Pin = i2c_pins.sda; \
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GPIO_InitStruct.Mode = GPIO_MODE_INPUT; \
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GPIO_InitStruct.Pull = GPIO_PULLUP; \
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GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH; \
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HAL_GPIO_Init(i2c_pins.group, &GPIO_InitStruct); \
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}while(0)
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#define SDA_OUT() do{ GPIO_InitTypeDef GPIO_InitStruct = {0}; \
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GPIO_InitStruct.Pin = i2c_pins.sda; \
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GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP; \
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GPIO_InitStruct.Pull = GPIO_PULLUP; \
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GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH; \
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HAL_GPIO_Init(i2c_pins.group, &GPIO_InitStruct); \
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}while(0)
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#define SCL_OUT() do{ GPIO_InitTypeDef GPIO_InitStruct = {0}; \
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GPIO_InitStruct.Pin = i2c_pins.scl; \
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GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP; \
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GPIO_InitStruct.Pull = GPIO_PULLUP; \
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GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH; \
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HAL_GPIO_Init(i2c_pins.group, &GPIO_InitStruct); \
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}while(0)
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#define SCL_H() HAL_GPIO_WritePin(i2c_pins.group, i2c_pins.scl, GPIO_PIN_SET)
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#define SCL_L() HAL_GPIO_WritePin(i2c_pins.group, i2c_pins.scl, GPIO_PIN_RESET)
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#define SDA_H() HAL_GPIO_WritePin(i2c_pins.group, i2c_pins.sda, GPIO_PIN_SET)
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#define SDA_L() HAL_GPIO_WritePin(i2c_pins.group, i2c_pins.sda, GPIO_PIN_RESET)
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#define READ_SDA() HAL_GPIO_ReadPin(i2c_pins.group, i2c_pins.sda)
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#define READ_SCL() HAL_GPIO_ReadPin(i2c_pins.group, i2c_pins.scl)
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static inline uint8_t I2c_WaitWhileClockStretching(uint16_t timeout)
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{
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while( timeout-- > 0 )
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{
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if( READ_SCL() )
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break;
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delay_us(1);
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}
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return timeout ? NO_ERROR : BUS_ERROR;
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}
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/* StartCondition(S) */
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uint8_t I2c_StartCondition()
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{
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uint8_t rv = NO_ERROR;
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SDA_OUT();
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SCL_OUT();
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/* StartCondition(S): A high to low transition on the SDA line while SCL is high.
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_______
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SCL: |___
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_____
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SDA: |_____
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*/
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SDA_H();
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delay_us(1);
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SCL_H();
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delay_us(1);
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C bus busy\n", __func__);
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return rv;
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}
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#endif
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SDA_L();
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delay_us(2);
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SCL_L();
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delay_us(2);
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return rv;
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}
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/* StopCondition(P) */
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uint8_t I2c_StopCondition(void)
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{
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uint8_t rv = NO_ERROR;
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SDA_OUT();
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/* StopCondition(P): A low to high transition on the SDA line while SCL is high.
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_____
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SCL: ___|
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_____
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SDA: _____|
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*/
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SCL_L();
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SDA_L();
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delay_us(2);
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SCL_H();
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delay_us(2);
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C bus busy\n", __func__);
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}
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#endif
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SDA_H();
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delay_us(2);
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return rv;
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}
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uint8_t I2c_WriteByte(uint8_t byte)
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{
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uint8_t rv = NO_ERROR;
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uint8_t mask;
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/* Data line changes must happened when SCL is low */
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SDA_OUT();
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SCL_L();
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/* 1Byte=8bit, MSB send: bit[7]-->bit[0] */
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for(mask=0x80; mask>0; mask>>=1)
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{
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if((mask & byte) == 0)
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SDA_L();
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else
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SDA_H();
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delay_us(1); // data set-up time (t_SU;DAT)
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SCL_H();
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delay_us(5); // SCL high time (t_HIGH)
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C bus busy\n", __func__);
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goto OUT;
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}
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#endif
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SCL_L();
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delay_us(1); // data hold time(t_HD;DAT)
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}
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/* clk #9 wait ACK/NAK from slave */
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SDA_IN();
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SCL_H(); // clk #9 for ack
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delay_us(1); // data set-up time (t_SU;DAT)
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C bus busy\n", __func__);
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goto OUT;
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}
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#endif
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/* High level means NAK */
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if( READ_SDA() )
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rv = ACK_ERROR;
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OUT:
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SCL_L();
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delay_us(20);
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return rv;
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}
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uint8_t I2c_ReadByte(uint8_t *byte, uint8_t ack)
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{
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uint8_t rv = NO_ERROR;
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uint8_t mask;
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*byte = 0x00;
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SDA_IN();
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/* 1Byte=8bit, MSB send: bit[7]-->bit[0] */
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for(mask = 0x80; mask > 0; mask >>= 1)
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{
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SCL_H(); // start clock on SCL-line
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delay_us(1); // clock set-up time (t_SU;CLK)
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C bus busy\n", __func__);
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goto OUT;
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}
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#endif
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if(READ_SDA())
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*byte |= mask; // read bit
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SCL_L();
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delay_us(1); // data hold time(t_HD;DAT)
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}
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/* clk #9 send ACK/NAK to slave */
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if(ack == ACK)
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{
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SDA_OUT();
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SDA_L(); // send Acknowledge if necessary
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}
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else if( ack == NAK )
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{
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SDA_OUT();
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SDA_H(); // send NotAcknowledge if necessary
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}
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delay_us(1); // data set-up time (t_SU;DAT)
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SCL_H(); // clk #9 for ack
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delay_us(2); // SCL high time (t_HIGH)
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C bus busy\n", __func__);
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}
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#endif
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OUT:
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SCL_L();
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delay_us(2); // wait to see byte package on scope
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return rv;
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}
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uint8_t I2c_SendAddress(uint8_t addr)
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{
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return I2c_WriteByte(addr);
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}
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int I2C_Master_Receive(uint8_t addr, uint8_t *buf, int len)
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{
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int i;
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int rv = NO_ERROR;
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uint8_t byte;
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I2c_StartCondition();
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rv = I2c_SendAddress(addr);
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if( rv )
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{
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i2c_print("Send I2C read address failure, rv=%d\n", rv);
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goto OUT;
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}
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#ifdef I2C_CLK_STRETCH_TIMEOUT
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/* wait while clock streching */
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rv = I2c_WaitWhileClockStretching(I2C_CLK_STRETCH_TIMEOUT);
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if( rv )
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{
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i2c_print("ERROR: %s() I2C wait clock stretching failure, rv=%d\n", __func__, rv);
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return rv;
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}
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#endif
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for (i=0; i<len; i++)
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{
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if( !I2c_ReadByte(&byte, ACK) )
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buf[i] = byte;
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else
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goto OUT;
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}
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OUT:
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I2c_StopCondition();
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return rv;
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}
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int I2C_Master_Transmit(uint8_t addr, uint8_t *data, int bytes)
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{
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int i;
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int rv = NO_ERROR;
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if(!data)
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{
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return PARM_ERROR;
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}
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i2c_print("I2C Mastr start transimit [%d] bytes data to addr [0x%02x]\n", bytes, addr);
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I2c_StartCondition();
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rv = I2c_SendAddress(addr);
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if( rv )
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{
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goto OUT;
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}
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for (i=0; i<bytes; i++)
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{
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if( NO_ERROR != (rv=I2c_WriteByte(data[i])) )
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{
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break;
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}
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}
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OUT:
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I2c_StopCondition();
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return rv;
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}
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