24c02.c

这是一个用于视频切换的控制程序,采用AT89C51芯片,KEIL 51开发

#define uchar unsigned char
#define uint unsigned int
#include "reg52.h"
#include "stdio.h"
#include "absacc.h"
#include "main.h"
#include "INTRINS.H"

uchar x24c02_read(uchar address);  //从24c02的地址address中读取一个字节数据
void x24c02_write(uchar address,uchar info);  //向24c02的address地址中写入一字节数据info
void x24c02_init();   //24c02初始化子程序
void delay1(uchar x);
void flash();
void x24c01_init();
void start();
void stop();
void writex(uchar j);
uchar readx();
void clock();
void delay1(uchar x)
{
   uint i;
   for(i=0;i<x;i++);
   DOG=~DOG;
}
void flash(void)
{
   _nop_();
   _nop_();
}
void x24c02_init()
{
   scl=1; flash(); sda=1; flash();
}
void start()
{
   sda=1; flash(); scl=1; flash(); sda=0; flash(); scl=0; flash();
}
void stop()
{
   sda=0; flash(); scl=1; flash(); sda=1; flash();
}
void writex(uchar j)
{
   uchar i,temp;
   temp=j;
   for (i=0;i<8;i++){
      temp=temp<<1; scl=0; flash(); sda=CY; flash(); scl=1; flash();
   }
   scl=0; flash(); sda=1; flash();
}
uchar readx()
{
   uchar i,j,k=0;
   scl=0; flash(); sda=1;
   for (i=0;i<8;i++){
      flash(); scl=1; flash();
      if (sda==1) j=1;
      else j=0;
      k=(k<<1)|j; scl=0;
   }
   flash(); return(k);
}
void clock()
{
   uchar i=0;
   scl=1; flash();
   while ((sda==1)&&(i<255))i++;
   scl=0; flash();
}
uchar x24c02_read(uchar address)
{
   uchar i;
   start(); writex(0xa0);
   clock(); writex(address);
   clock(); start();
   writex(0xa1); clock();
   i=readx(); stop();
   delay1(10);
   return(i);
}
void x24c02_write(uchar address,uchar info)
{
   EA=0;
   start(); writex(0xa0);
   clock(); writex(address);
   clock(); writex(info);
   clock(); stop();
   EA=1;
   delay1(50);
}