[嵌入式]9.基于STM32CubeMx软件模拟I2C通信

使用：

		MEM_Write (ReceiveString,0x01,4);
		HAL_Delay (1000);
		MEM_Read (I2CString,0x01,4);

驱动程序（最后两个自己编写，其余底层驱动官方提供）

#include "i2c.h"

//#define DELAY_TIME	20
#define DELAY_TIME 20

//PB6_SCL
//PB7_SDA
/**
  * @brief SDA线输入模式配置
  * @param None
  * @retval None
  */
void SDA_Input_Mode()
{
    GPIO_InitTypeDef GPIO_InitStructure = {0};

    GPIO_InitStructure.Pin = GPIO_PIN_7;
    GPIO_InitStructure.Mode = GPIO_MODE_INPUT;
    GPIO_InitStructure.Pull = GPIO_PULLUP;
    GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/**
  * @brief SDA线输出模式配置
  * @param None
  * @retval None
  */
void SDA_Output_Mode()
{
    GPIO_InitTypeDef GPIO_InitStructure = {0};

    GPIO_InitStructure.Pin = GPIO_PIN_7;
    GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_OD;
    GPIO_InitStructure.Pull = GPIO_NOPULL;
    GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/**
  * @brief SDA线输出一个位
  * @param val 输出的数据
  * @retval None
  */
void SDA_Output( uint16_t val )
{
    if ( val )
    {
        GPIOB->BSRR |= GPIO_PIN_7;
    }
    else
    {
        GPIOB->BRR |= GPIO_PIN_7;
    }
}

/**
  * @brief SCL线输出一个位
  * @param val 输出的数据
  * @retval None
  */
void SCL_Output( uint16_t val )
{
    if ( val )
    {
        GPIOB->BSRR |= GPIO_PIN_6;
    }
    else
    {
        GPIOB->BRR |= GPIO_PIN_6;
    }
}

/**
  * @brief SDA输入一位
  * @param None
  * @retval GPIO读入一位
  */
uint8_t SDA_Input(void)
{
	if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7) == GPIO_PIN_SET){
		return 1;
	}else{
		return 0;
	}
}


/**
  * @brief I2C的短暂延时
  * @param None
  * @retval None
  */
static void delay1(unsigned int n)
{
    uint32_t i;
    for ( i = 0; i < n; ++i);
}

/**
  * @brief I2C起始信号
  * @param None
  * @retval None
  */
void I2CStart(void)
{
    SDA_Output(1);
    delay1(DELAY_TIME);
    SCL_Output(1);
    delay1(DELAY_TIME);
    SDA_Output(0);
    delay1(DELAY_TIME);
    SCL_Output(0);
    delay1(DELAY_TIME);
}

/**
  * @brief I2C结束信号
  * @param None
  * @retval None
  */
void I2CStop(void)
{
    SCL_Output(0);
    delay1(DELAY_TIME);
    SDA_Output(0);
    delay1(DELAY_TIME);
    SCL_Output(1);
    delay1(DELAY_TIME);
    SDA_Output(1);
    delay1(DELAY_TIME);

}

/**
  * @brief I2C等待确认信号
  * @param None
  * @retval None
  */
unsigned char I2CWaitAck(void)
{
    unsigned short cErrTime = 5;
    SDA_Input_Mode();
    delay1(DELAY_TIME);
    SCL_Output(1);
    delay1(DELAY_TIME);
    while(SDA_Input())
    {
        cErrTime--;
        delay1(DELAY_TIME);
        if (0 == cErrTime)
        {
            SDA_Output_Mode();
            I2CStop();
            return ERROR;
        }
    }
    SDA_Output_Mode();
    SCL_Output(0);
    delay1(DELAY_TIME);
    return SUCCESS;
}

/**
  * @brief I2C发送确认信号
  * @param None
  * @retval None
  */
void I2CSendAck(void)
{
    SDA_Output(0);
    delay1(DELAY_TIME);
    delay1(DELAY_TIME);
    SCL_Output(1);
    delay1(DELAY_TIME);
    SCL_Output(0);
    delay1(DELAY_TIME);

}

/**
  * @brief I2C发送非确认信号
  * @param None
  * @retval None
  */
void I2CSendNotAck(void)
{
    SDA_Output(1);
    delay1(DELAY_TIME);
    delay1(DELAY_TIME);
    SCL_Output(1);
    delay1(DELAY_TIME);
    SCL_Output(0);
    delay1(DELAY_TIME);

}

/**
  * @brief I2C发送一个字节
  * @param cSendByte 需要发送的字节
  * @retval None
  */
void I2CSendByte(unsigned char cSendByte)
{
    unsigned char  i = 8;
    while (i--)
    {
        SCL_Output(0);
        delay1(DELAY_TIME);
        SDA_Output(cSendByte & 0x80);
        delay1(DELAY_TIME);
        cSendByte += cSendByte;
        delay1(DELAY_TIME);
        SCL_Output(1);
        delay1(DELAY_TIME);
    }
    SCL_Output(0);
    delay1(DELAY_TIME);
}

/**
  * @brief I2C接收一个字节
  * @param None
  * @retval 接收到的字节
  */
unsigned char I2CReceiveByte(void)
{
    unsigned char i = 8;
    unsigned char cR_Byte = 0;
    SDA_Input_Mode();
    while (i--)
    {
        cR_Byte += cR_Byte;
        SCL_Output(0);
        delay1(DELAY_TIME);
        delay1(DELAY_TIME);
        SCL_Output(1);
        delay1(DELAY_TIME);
        cR_Byte |=  SDA_Input();
    }
    SCL_Output(0);
    delay1(DELAY_TIME);
    SDA_Output_Mode();
    return cR_Byte;
}

//
void I2CInit(void)
{
		GPIO_InitTypeDef GPIO_InitStructure = {0};

    GPIO_InitStructure.Pin = GPIO_PIN_7 | GPIO_PIN_6;
    GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStructure.Pull = GPIO_PULLUP;
    GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStructure);
}
void MEM_Write(unsigned char *pucBuf,unsigned char ucAddr,unsigned char ucNum)
{
		I2CStart();
		I2CSendByte(0xA0);
		I2CWaitAck();
	
		I2CSendByte (ucAddr);
		I2CWaitAck();
	
		for(uint8_t i=0;i<ucNum;i++)
		{
			I2CSendByte (pucBuf[i]);
				I2CWaitAck();
		}
		I2CStop();
	
}
void MEM_Read(unsigned char *pucBuf,unsigned char ucAddr,unsigned char ucNum)
{
		I2CStart();
		I2CSendByte(0xA0);
		I2CWaitAck();
	
		I2CSendByte (ucAddr);
		I2CWaitAck();
	
		I2CStart();
		I2CSendByte(0xA1);
		I2CWaitAck();
	
		for(uint8_t i=0;i<ucNum;i++)
		{
			pucBuf[i]=I2CReceiveByte ();
			if(i==ucNum-1)
				I2CSendNotAck();
			else
				I2CSendAck();
		}
		I2CStop();
	
}