STM32 HAL库 模拟I²C

在使用单片机的过程中，I²C总线是常用的一种通信方式，然而由于某些原因，STM32CubeMx直接初始化I²C会出现接收不到信息和各种问题，为此我们需要使用IO口来模拟I²C。

I²C的简介：

https://www.bilibili.com/opus/591043733946717098

用STM32CubeMx初始化模拟I²C的引脚：

STM32CubeMx的GPIO的配置可以参考： 

https://www.bilibili.com/opus/484177792198506654

所用到的两个IO口分别对应I²C总线的串行数据线和串行时钟线。

SDA：PB7

SCL：PB6

头文件和源文件皆是依据正点原子mini32开发板的标准库文件学习修改得来

user_iic.h

#ifndef __USER_IIC_H

#define __USER_IIC_H

#ifdef __cplusplus

extern "C"

{

#endif

#include "stm32f1xx_hal.h"

#define SCL_H HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET)

#define SCL_L HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET)

#define SDA_H HAL_GPIO_WritePin(GPIOB, GPIO_PIN_7, GPIO_PIN_SET)

#define SDA_L HAL_GPIO_WritePin(GPIOB, GPIO_PIN_7, GPIO_PIN_RESET)

#define SDA_read HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7)

void SDA_IN(void);

void SDA_OUT(void);

void IIC_Init(void); //初始化IIC的IO口

void IIC_Start(void); //发送IIC开始信号

void IIC_Stop(void); //发送IIC停止信号

uint8_t IIC_Wait_Ack(void); // IIC等待ACK信号

void IIC_Ack(void); // IIC发送ACK信号

void IIC_NAck(void); // IIC不发送ACK信号

void IIC_Send_Byte(uint8_t txd); // IIC发送一个字节

uint8_t IIC_Read_Byte(uint8_t ack); // IIC读取一个字节

#ifdef __cplusplus

}

#endif

#endif

user_iic.c

/**

 * @file

 * @brief user_iic.c

 * @details     Simulate iic source file

 * @author wingplane

 * @date 2021-11-09

 * @version     v1.0

 */

#include "user_iic.h"

#include "stdio.h"

/**

 * @brief SDA_IN

 * @details     Change the SDA pin to read

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void SDA_IN(void)

{

GPIO_InitTypeDef GPIO_InitStruct = {0};

GPIO_InitStruct.Pin = GPIO_PIN_7;

GPIO_InitStruct.Mode = GPIO_MODE_INPUT;

GPIO_InitStruct.Pull = GPIO_PULLUP;

GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

}

/**

 * @brief user_SDA_OUT

 * @details     Change the SDA pin to write

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void SDA_OUT(void)

{

GPIO_InitTypeDef GPIO_InitStruct;

GPIO_InitStruct.Pin = GPIO_PIN_7;

GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;

GPIO_InitStruct.Pull = GPIO_NOPULL;

GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

}

/**

 * @brief IIC_Init

 * @details     IIC initialization

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void IIC_Init(void)

{

SDA_H;

SCL_H;

}

/**

 * @brief IIC_Start

 * @details     Master Start Simulation IIC Communication

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void IIC_Start(void)

{

SDA_OUT(); // SDA set output

SDA_H;

SCL_H;

HAL_Delay(4);

SDA_L; // START:when CLK is high,DATA change form high to low

HAL_Delay(4);

SCL_L; // Clamp the I2C bus, ready to send or receive data

}

/**

 * @brief IIC_Stop

 * @details     Master Stop Simulation IIC Communication

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void IIC_Stop(void)

{

SDA_OUT(); // SDA set output

SCL_L;

SDA_L; // STOP:when CLK is high DATA change form low to high

HAL_Delay(4);

SCL_H;

SDA_H; // Send I2C bus end signal

HAL_Delay(4);

}

/**

 * @brief IIC_Wait_Ack

 * @details     Master Reserive Slave Acknowledge Single

 * @param[in] None

 * @param[out] None

 * @retval 1   Receive Response Fail

 * @retval 0   Receive Response Success

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

uint8_t IIC_Wait_Ack(void)

{

uint8_t ucErrTime = 0;

SDA_IN(); // SDAset output

SDA_H;

HAL_Delay(1);

SCL_H;

HAL_Delay(1);

while (SDA_read)

{

ucErrTime++;

if (ucErrTime > 250)

{

IIC_Stop();

return 1;

}

}

SCL_L; //clk output0

return 0;

}

/**

 * @brief IIC_Ack

 * @details     Master Send Acknowledge Single

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void IIC_Ack(void)

{

SCL_L;

SDA_OUT();

SDA_L;

HAL_Delay(2);

SCL_H;

HAL_Delay(2);

SCL_L;

}

/**

 * @brief IIC_NAck

 * @details     Master Send No Acknowledge Single

 * @param[in] None

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void IIC_NAck(void)

{

SCL_L;

SDA_OUT();

SDA_H;

HAL_Delay(2);

SCL_H;

HAL_Delay(2);

SCL_L;

}

/**

 * @brief IIC_Send_Byte

 * @details     Master Send a Byte to Slave

 * @param[in] txd Will Send Date

 * @param[out] None

 * @retval None

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

void IIC_Send_Byte(uint8_t txd)

{

uint8_t t;

SDA_OUT();

SCL_L; //Start data transfer

for (t = 0; t < 8; t++)

{

// IIC_SDA=(txd&0x80)>>7;

if ((txd & 0x80) >> 7)

SDA_H;

else

SDA_L;

txd <<= 1;

HAL_Delay(2);

SCL_H;

HAL_Delay(2);

SCL_L;

HAL_Delay(2);

}

}

/**

 * @brief I2C_Rade_Byte

 * @details     Master Reserive a Byte From Slave

 * @param[in] ack If the value is 1,send the ACK.If the value is 0, send the nACK

 * @param[out] receive

 * @retval Date From Slave

 * @par Modification log

 * Created by wingplane on 2021-11-09

 */

uint8_t IIC_Read_Byte(unsigned char ack)

{

unsigned char i, receive = 0;

SDA_IN(); // SDAset output

for (i = 0; i < 8; i++)

{

SCL_L;

HAL_Delay(2);

SCL_H;

receive <<= 1;

if (SDA_read)

receive++;

HAL_Delay(1);

}

if (!ack)

IIC_NAck(); //发送nACK

else

IIC_Ack(); //发送ACK

return receive;

}

参考文献：

STM32不完全手册_标准库版本_V3.3