单片机快速入门-I2C总线操作.doc

I2C总线操作2010-11-01 11:32:44编程：定义：#define WriteDeviceAddress 0xa0#define ReadDviceAddress 0xa1sbit SCL=P10;sbit SDA=P11;其实在调用函数时，真正需要用到的是如下两个函数：void WriteI2C(unsigned char *Wdata,unsigned char RomAddress,unsigned char number)写三要素：写什么？写到哪里？写几位？如：WriteI2C(addw,0x00,8);写ADDW指针的数据，到以0X00开始的空间，连续写8位。void ReadI2C(unsigned char *RamAddress,unsigned char RomAddress,unsigned char bytes)读三要素：放到哪里？从哪里开始读？读几位？如：ReadI2C(addr,0x00,1);从0X00单元读入1位，放到ADDR指针指向的单片机中。当然，从哪里读，需要一个数组空间，读完以后也需要一个数组空间，可以如下定义：unsigned char writeByte8=0xC0,0x34,0x12,0x11,0x22,0x01,0x00,0x00;/写8个字节USB数据IDunsigned char readByte8;为了方便使用，定义指向数组的指针：unsigned char *addw;unsigned char *addr;addw=writeByte; addr=readByte;当然也可以设置读写的标记，当write=1时，可实现读写。if(write=1)下面是IIC通信协议程序：void DelayMs(unsigned int number)unsigned char temp;for(;number!=0;number-,DOG=!DOG)for(temp=112;temp!=0;temp-)/*/void Start() SDA=1; DelayMs(1); SCL=1; DelayMs(1); SDA=0; DelayMs(1); SCL=0; DelayMs(1);/*/void Stop() SCL=0; DelayMs(1); SDA=0; DelayMs(1); SCL=1; DelayMs(1); SDA=1; DelayMs(1);/*/void Ack() SDA=0; DelayMs(1); SCL=1; DelayMs(1); SCL=0; DelayMs(1); SDA=1; DelayMs(1);/*/void NoAck() SDA=1; DelayMs(1); SCL=1; DelayMs(1); SCL=0; DelayMs(1);/*/bit TestAck() bit ErrorBit; SDA=1; DelayMs(1); SCL=1; DelayMs(1); ErrorBit=SDA; DelayMs(1); SCL=0; DelayMs(1); return(ErrorBit);/*/bit Write8Bit(unsigned char input) unsigned char temp; for(temp=8;temp!=0;temp-) SDA=(bit)(input&0x80); DelayMs(1); SCL=1; DelayMs(1); SCL=0; DelayMs(1); input=input1; return 1;/*/void WriteI2C(unsigned char *Wdata,unsigned char RomAddress,unsigned char number) Start(); Write8Bit(WriteDeviceAddress); TestAck(); Write8Bit(RomAddress); TestAck(); for(;number!=0;number-) Write8Bit(*Wdata); TestAck(); Wdata+; Stop(); DelayMs(10);/*/unsigned char Read8Bit() unsigned char temp,rbyte=0; for(temp=8;temp!=0;temp-) SCL=1; DelayMs(1); rbyte=rbyte1; DelayMs(1); rbyte=rbyte|(unsigned char)(SDA); SCL=0; DelayMs(1); return(rbyte);/*/void ReadI2C(unsigned char *RamAddress,unsigned char RomAddress,unsigned char bytes) Start(); Write8Bit(WriteDeviceAddress); TestAck(); Write8Bit(RomAddress); TestAck(); Start(); Write8Bit(ReadDviceAddress); TestAck(); whi