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/*****************************IIC通信协议***************************/

#define _IIC11

#define _IIC20

#define IIC1_SCLPB6

#define IIC1_SDAPB7

#define IIC2_SCL PB10

#define IIC2_SDAPB11

#if _IIC1

#define SDA_IN(){GPIOB->CRL &= 0X0FFFFFFF; GPIOB->CRL |= (u32)8<<28;}

#define SDA_OUT(){GPIOB->CRL &= 0X0FFFFFFF; GPIOB->CRL |= (u32)3<<28;}

#endif

#if _IIC2

#define SDA_IN(){GPIOB->CRH &= 0XFFFF0FFF; GPIOB->CRH |= (u32)8<<12;}

#define SDA_OUT(){GPIOB->CRH &= 0XFFFF0FFF; GPIOB->CRH |= (u32)3<<12;}

#endif

#define IIC1_SCL_HighwriteGpioHigh(IIC1_SCL)

#define IIC1_SCL_LowwriteGpioLow(IIC1_SCL)

#define IIC1_SDA_HighwriteGpioHigh(IIC1_SDA)

#define IIC1_SDA_LowwriteGpioLow(IIC1_SDA)

#define IIC2_SCL_HighwriteGpioHigh(IIC2_SCL)

#define IIC2_SCL_LowwriteGpioLow(IIC2_SCL)

#define IIC2_SDA_HighwriteGpioHigh(IIC2_SDA)

#define IIC2_SDA_LowwriteGpioLow(IIC2_SDA)

void iicStart(void)

{

SDA_OUT();    //sda线输出

IIC1_SCL_High;

IIC1_SDA_High;

delayNop(2);

IIC1_SDA_Low;

delayNop(2);

IIC1_SCL_Low;   //钳住I2C总线，准备发送或接收数据 

}

void iicStop(void)

{

SDA_OUT();     //sda线输出

IIC1_SDA_Low;

IIC1_SCL_Low;

delayNop(2);

IIC1_SCL_High;

IIC1_SDA_High;

delayNop(2);

}

u8 iicWaitAck(void)

{

u8 errorAck = 0;

SDA_IN();

IIC1_SCL_High;

delayNop(2);

IIC1_SDA_High;

delayNop(2);

while( GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_7) == Bit_SET )

{

errorAck++;

if(errorAck > 250)

{

iicStop();

return 0;

}

}

IIC1_SCL_Low;

return 1;

}

//产生应答

void iicACK(void)

{

IIC1_SCL_Low;

SDA_OUT();

IIC1_SDA_Low;

delayNop(2);

IIC1_SCL_High;

delayNop(2);

IIC1_SCL_Low;

}

void iicNOack(void)

{

IIC1_SCL_Low;

SDA_OUT();

IIC1_SDA_High;

delayNop(2);

IIC1_SCL_High;

delayNop(2);

IIC1_SCL_Low;

}

void iicWrite_Byte(u8 byte)

{

u8 i;

SDA_OUT();

IIC1_SCL_Low;

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

{

if( (byte&0x80) == 0x80 )

{

IIC1_SDA_High;

}

else

{

IIC1_SDA_Low;

}

byte <<= 1;

delayNop(2);

IIC1_SCL_High;

delayNop(2);

IIC1_SCL_Low;

delayNop(2);

}

}

//读1个字节(高位开始读)，ack=1时，发送ACK，ack=0，发送nACK  

//在C语言中x<<=1等于x=x<<1，是把x左移1位以后值保存回x里，x发生变化了

u8 iicRead_Byte(unsigned char ack)

{

u8 i;

u8 recvByte = 0;

SDA_IN();

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

{

IIC1_SCL_Low;

delayNop(2);

recvByte <<= 1;//高位开始读，所以左移

if( GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_7) == Bit_SET )

{

recvByte |= 0x01; 

}

delayNop(2);

}

if(ack)

{

iicACK();

}

else

{

iicNOack();

}

return recvByte;

}

//------- 延时子程序

//系统时钟为24M时

//count = 200时，时间约等于100us

void delayNop(u32 count)

{

while(count -- > 0)

{

__NOP();

}

}