I2C总线模拟（郭天祥视屏）

电路图

思路

1.向EEPROM中通过I2C总线写入一个字节

2.通过I2C总线读出写入的字节

3.如果写入和读出成功点亮发光二极管

程序

 #include <REGX51.H>

 #define uchar unsigned char
 #define uint unsigned int

 void init();
 void start();
 void stop();
 void write(uchar byte);
 void write_add(uchar byte,uchar address);//向指定地址中写入字节
 void delay1(uchar x);
 uchar read_add(uchar address);
 uchar read();//从指定地址中读出字节

 void delay()
 {;;}

 sbit led = P0^;
 sbit sck = P2^;
 sbit sad = P2^;

 void main()
 {
     uchar test = ;
     init();
     write_add(0x01,0xaf);
     delay1();

     test =read_add(0xaf);
     if(test == 0x01)
         led = ;
     while();
 }

 void init()
 {
     sck = ;
     delay();
     sad = ;//数据线和信号线都空闲
     delay();
     led = ;
 }
 //起始信号
 void start()
 {
     sad = ;
     delay();
     sck = ;
     delay();
     sad = ;
     delay();
 }
 //停止信号
 void stop()
 {
     sad = ;
     delay();
     sck = ;
     delay();
     sad = ;
     delay();
 }
 //等待回应
 void response()
 {
     uchar i = ;
     sck = ;
     delay();
     while((sad == ) && (i < ))
         i++;
     sck = ;
     delay();
 }
 //向指定地址写入一个字节
 void write(uchar byte)
 {
     uchar i = ;
     uchar temp = byte;

     for(; i < ; i++)
     {
         temp = temp << ;//temp左移一位
         sck = ;
         delay();
         sad = CY;
         delay();
         sck = ;
         delay();
     }
     sck = ;
     delay();//这样就不会产生开始信号或结束信号
     sad = ;
     delay();
 }
 //从指定地址读取一个字符
 uchar read()
 {
     uchar i,k;
     sck = ;
     delay();
     sad = ;
     delay();
     for(; i < ; i++)
     {
         sck = ;
         delay();
         k = (k << ) | sad;
         sck = ;
         delay();
     }
     return k;
 }
 //写入一个字节
 void write_add(uchar byte,uchar address)
 {
     start();
     write(0xa0);
     response();
     write(address);
     response();
     write(byte);
     response();
     stop();
 }
 //读出写入的字节
 uchar read_add(uchar address)
 {
     uchar result;
     start();
     write(0xa0);
     response();
     write(address);
     response();
     start();
     write(0xa1);
     response();
     result = read();
     stop();
     return result;
 }
 void delay1(uchar x)
 {
     uchar a,b;
     for(a=x;a>;a--)
      for(b=;b>;b--);
 }

运行结果