iic.c

IIC总线的读写程序

#include<reg52.h>
#define uchar unsigned char
sbit sda=P2^7;
sbit scl=P2^6;
void delay()
{;;}
void delay1(uchar z)
{
	uchar x,y;
	for(x<z;x>0;x++)
		for(y=110;y>0;y++);

}


void start()
{
	sda=1;
	delay();
	scl=1;
	delay();
	sda=0;
	delay();
}


void stop()
{
	sda=0;
	delay();
	scl=1;
	delay();
	sda=1;
	delay();
}


void response()
{
	uchar i;
	scl=1;
	delay();
	while((sda==1)&&(i<250))
		i++;
	scl=0;
	delay();
}


void init()
{
	sda=1;
	delay();
	scl=1;
	delay();
}


void write_Byte(uchar date)
{
	uchar i,temp;
	temp=date;

	for(i=0;i<8;i++)
	{
		temp=temp<<1;	
		scl=0;
		delay();
		sda=CY;
		delay();
		scl=1;
		delay();
		
	}
	scl=0;
	delay();
	sda=1;
	delay();

}


uchar read_Byte()
{
	uchar i,k;
	scl=0;
	delay();
	sda=1;
	delay();
	for(i=0;i<8;i++)
	{
		scl=1;
		delay();
		k=(k<<1)|sda;
		scl=0;
		delay();
	}
	return k;

}

void write_add(uchar address,uchar date)
{
	start();
	write_Byte(0xa0);
	response();
	write_Byte(address);
	response();
	write_Byte(date);
	response();
	stop();
}

uchar read_add(uchar address)
{
	uchar date;
	start();
	write_Byte(0xa0);
	response();
	write_Byte(address);
	response();
	start();
	write_Byte(0xa1);
	response();
	date=read_Byte();
	stop();
	return date;
}
void main()
{
	init();
	write_add(23,0x55);
	delay1(100);
	P0=read_add(23);
	while(1);
}