I2C 模拟读写代码

static void Delay1us(void)//please revise this function according to your system
{
	u8 i;
	for(i=0;i<15;i++);
}






void I2C_init(void)
{
	// SDA CLK初始化
	GPIOE->DDR|=((1<<I2C_SCK));				// I2C_SDA I2C_SCK output
	GPIOE->CR1|= ((1<<I2C_SCK));				// I2C_SDA I2C_SCK output推挽输出
	GPIOE->CR2&= ~((1<<I2C_SCK));				// Toggle GPIO PIN PB 无中断
	GPIOE->ODR|=(1<<I2C_SCK);					// I2C_SDA I2C_SCK=1
	
	GPIOE->DDR|=((1<<I2C_SDA));				// I2C_SDA I2C_SCK output
	GPIOE->CR1|= ((1<<I2C_SDA));				// I2C_SDA I2C_SCK output推挽输出
	GPIOE->CR2&= ~((1<<I2C_SDA));				// Toggle GPIO PIN PB 无中断
	GPIOE->ODR|=(1<<I2C_SDA);	
	

}


void I2C_Start(void)
{
	I2C_DATA_HIGH;
	Delay1us();
	I2C_CLK_HIGH;
	Delay1us();
	I2C_DATA_LOW;
	Delay1us();
	I2C_CLK_LOW;
	Delay1us();
}

void I2C_Stop(void)
{
    I2C_CLK_LOW;
    Delay1us();
    I2C_DATA_LOW;
    Delay1us();
    I2C_CLK_HIGH;
    Delay1us();
    I2C_DATA_HIGH;
    Delay1us();
}


void I2C_ack(void)
{
    I2C_SDA_DIROUT;
	GPIOE->CR1|= (1<<I2C_SDA);
    I2C_CLK_LOW;
    I2C_DATA_LOW;
    Delay1us();

    I2C_CLK_HIGH;
    Delay1us();
    I2C_CLK_LOW;
}      

void I2C_nack(void)
{
    I2C_SDA_DIROUT;
	GPIOE->CR1|= (1<<I2C_SDA);
    I2C_CLK_LOW;
    I2C_DATA_HIGH;
    Delay1us();

    I2C_CLK_HIGH;
    Delay1us();
    I2C_CLK_LOW;
}



u8 I2C_ReceiveACK(void)
{
  	u8 ackflag;
    I2C_SDA_DIRIN;
	GPIOE->CR1&= ~(1<<I2C_SDA);
    Delay1us();
    I2C_CLK_HIGH;
    Delay1us();
    ackflag = (u8)I2C_DATA_READ;
    I2C_CLK_LOW;
    I2C_SDA_DIROUT;
	GPIOE->CR1|= (1<<I2C_SDA);
    Delay1us();
    return ackflag;
}



void I2C_sendbyte(u8 I2CSendData)
{
   
	u8	i;
	Delay1us();
	I2C_CLK_LOW;
	for(i = 0;i < 8;i++)
	{
		if(I2CSendData & 0x80)I2C_DATA_HIGH;					//if high bit is 1,SDA= 1
		else I2C_DATA_LOW;							  //else SDA=0
		Delay1us();
		I2C_CLK_HIGH;
		Delay1us();
		I2CSendData <<= 1;								//shift left 1 bit
		I2C_CLK_LOW;
	}				
}



u8 I2c_Readbyte(void)
{
    u8 i;
    u8 ucRDData = 0;                     //return value
    
    I2C_SDA_DIRIN;
	GPIOE->CR1&= ~(1<<I2C_SDA);
    Delay1us();;
    for(i = 0;i < 8;i++)
    {
        I2C_CLK_HIGH;
        ucRDData <<= 1;
        Delay1us();
        if(I2C_DATA_READ)
    	{
    		//beep(BEEP_KEY);
    		  ucRDData|=0x01;
    	}
          
        I2C_CLK_LOW;
        Delay1us();
		
    }
    return(ucRDData);
}



void I2c_Read(u8 adr,u8 *pBuf,u8 CMD)
{

	u8 buff;
	I2C_Start();
	I2C_sendbyte(adr); 
	buff=I2C_ReceiveACK();
	if(buff!=0)
	{
		tiic=1;
		return;
	}
	else tiic=0;

	I2C_sendbyte(CMD);
		buff=I2C_ReceiveACK();
	if(buff!=0)
	{
		tiic=2;
		return;
	}

	I2C_Start();
	I2C_sendbyte(adr+1);   
	buff=I2C_ReceiveACK();
	if(buff!=0)
	{
		tiic=3;
		return;
	}

	*pBuf = I2c_Readbyte();
	I2C_ack();

	*pBuf = I2c_Readbyte();
	tiic=*pBuf;
	I2C_nack();

	I2C_Stop();
}

void I2c_Write(u8 adr,u8* pBuf,u8 CMD)
{
 

	I2C_Start();

	I2C_sendbyte(adr);
	I2C_ReceiveACK();

	I2C_sendbyte(CMD);	 
	I2C_ReceiveACK();
	 
   
	I2C_sendbyte(*pBuf);
	I2C_ReceiveACK(); 
	
	I2C_Stop();
}



	  I2c_Read(0x80,&key80,0x08);                 //p
	mKEY.key_input|=key80;