#include"reg52.h"
#define uchar unsigned char
uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
sbit wl=P2^0;
sbit du=P2^1;
sbit scl=P3^4;
sbit sda=P3^5;

uchar flag,a;

void delay()
{
	; ;
}

void delay2(int z)
{
	uchar x,y;
	for(x=110;x>0;x--)
	   for(y=z;y>0;y--);
}

void display(uchar temp)
{
	uchar shi,ge;
	shi=temp/10;
	ge=temp%10;
	wl=1;
	P1=0xfe;
	wl=0;
	du=1;
	P1=table[shi];
	delay2(2);
	du=0;
	wl=1;
	P1=0xfd;
	wl=0;
	du=1;
	P1=table[ge];
	delay2(2);
	du=0;
}

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

void write(uchar add ,uchar date)
{
	 start();
	 writebyte(0xa0);
	 response();
	 writebyte(add);
	 response();
	 writebyte(date);
	 response();
	 stop();
}

uchar read(uchar add)
{
    uchar temp;
	start();
	writebyte(0xa0);
	response();
	writebyte(add);
	response();
	start();
	writebyte(0xa1);
	response();
    temp=readbyte();
	stop();
	return(temp);
}

void init()
{
	TMOD=0x01;
	TH0=0x4c;
	TL0=0x00;
	EA=1;
	ET0=1;
	TR0=1;
}

void main()
{
    a=read(2);
    init();
	while(1)
	{
		if(flag==20)
		{
			flag=0;
			a++;
			if(a==100)
			a=0;
			write(2,a);
		}
		display(a);
		
	}
}

void timer0() interrupt 1
{
	 TH0=0x4c;
	 TL0=0x00;
	 flag++;
}