text1.c

基于80c51的模拟IIC时序

#include "reg51.h"
#define uchar unsigned char
#define uint unsigned int
sbit sda=P1^0;      
sbit scl=P1^1;
void IIC_delay(uchar x);
void flash();
void x24c02_init();
void start(); 
void stop();
void writex(uchar j);
uchar readx();
void clock();
uchar x24c02_read(uchar address);
void x24c02_write(uchar address,uchar info);
void delay10ms(void);
void IIC_delay(uchar x)
{  
	uint i;
	for(i=0;i<x;i++);
}

void flash()
{  ;  ; }
void x24c02_init()  //24c02初始化子程序
{
	scl=1; 
	flash(); 
	sda=1; 
	flash();
}
void start()        //启动I2C总线
{
	sda=1; 
	flash(); 
	scl=1; 
	flash(); 
	sda=0; 
	flash(); 
	scl=0; 
	flash();
}
void stop()         //停止I2C总线
{
	sda=0; 
	flash(); 
	scl=1; 
	flash(); 
	sda=1; 
	flash();
}
void writex(uchar j)  //写一个字节
{  
	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()   //读一个字节
{
	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()         //I2C总线时钟
{
	uchar i=0;
	scl=1; 
	flash();
	while ((sda==1)&&(i<255))i++;
	scl=0; 
	flash();
}

////////从24c02的地址address中读取一个字节数据/////uchar x24c02_read(uchar address)
uchar x24c02_read(uchar address)
{
	uchar i;
	start(); 
	writex(0xa0);
	clock(); 
	writex(address);
	clock(); 
	start();
	writex(0xa1); 
	clock();
	i=readx(); 
	stop();
	IIC_delay(10);
	return(i);
}

//////向24c02的address地址中写入一字节数据info/////

void x24c02_write(uchar address,uchar info)
{
	EA=0;
	start(); 
	writex(0xa0);
	clock(); 
	writex(address);
	clock(); 
	writex(info);
	clock(); 
	stop(); 
	EA=1;
	IIC_delay(100);
}
main()
{
 x24c02_init();
 x24c02_write(00,0x11);
 P3=x24c02_read(00);
 while(1);
}