求助！！！各位大神请进！！！

只看该作者 · 2014-7-3 20:28

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit scl=P3^4;
sbit sda=P3^5 ;
void delay()
{;;}
void delay1(uchar x)
{
      uchar i,j;
      for(i=x;i>0;i--);
      for(j=100;j>0;j--);
}

void start()  //起始信号
{
      sda=1;
      delay();
      scl=1;
      delay();
      sda=0;
      delay();
}
void stop()       //停止信号
{
      sda=0;
      delay();
      scl=1;
      delay();
      sda=1;
      delay();
}
void ask()       //应答
{
      uchar i;
      scl=1;
      delay();
      while((sda==1)&&(i<250))
      i++;
      scl=0;
      delay();
}
void write_byte(uchar date)       //写入一个字节
{
      uchar i,temp;
      temp=date;
//       scl=0;
      //delay();
      for(i;i<8;i++)
      {
            temp=temp<<1;
            scl=0;
            delay();
            sda=CY;
            delay();
            scl=1;
            delay();
      }
      scl=0;
      delay();
      sda=1;
      delay();
}
uchar read_byte() //读取一个字节
{
      uchar i,j,k;
      scl=0;
      delay();
      sda=1;
      delay();
      for(i;i<8;i++)
      {
            scl=1;
            delay();
            j=sda;
            k=(k<<1)|j;
            scl=0;
            delay();
      }
      delay();
      return k;
}
void init()                //初始化
{
      scl=1;
      sda=1;
}
void write_add(uchar address,uchar date)//指定地址写数据
{
      start();
      write_byte(0xa0);
      ask();
      write_byte(address);
      ask();
      write_byte(date);
      ask();
      stop();
}
uchar read_add(uchar address)       //指定地址读
{
      uchar date;
      start();
      write_byte(0xa0);
      ask();
      write_byte(address);
      ask();
start();
write_byte(0xa1);
ask();
date=read_byte();
stop();
return date;
}
void main()
{
      init();
      write_add(3,0xaa);
      delay1(1000);
      P0=read_add(3);
      while(1);
}分析分析为什么p0输出的是0xa1;并且改变write_byte(0Xa1)括号里的参数，P0输出改变