#include <reg52.h>
#define	uchar unsigned	char
#define	uint  unsigned	int

sbit	P10=P1^0;
sbit	P11=P1^1;
	
void	init();
void	display();
void	delay(uint z);

int	num;
uchar	t0,gw,shw,bw;
uchar	code table[]=
		{
		0xc0,0xf9,0xa4,
		0xb0,0x99,0x92,
		0x82,0xf8,0x80,0x90		//共陽數(shù)碼管顯示的0~9	
		};

void	main()
{	 
	  	init();
		delay(50);
	while(1)
	{	
		display();
		
	}
}
void	init()			  //初始化函數(shù)
{
	num=995;
	TMOD=0X11;
	TH0=(65536-50000)/256;
	TL0=(65536-50000)%256;
	EA=1;
	ET0=1;
	TR0=1;

}
void	display()
{	
	P3=0xdf;
	P0=table[bw];
	delay(1);
	P3=0xbf;			//作為位選的P3.6、P3.7一定要放在段選之前P0前打開！
	P0=table[shw];		// 現(xiàn)在還不知原因
	delay(1);
	P3=0x7f;
	P0=table[gw];
	delay(1);

}

void	timer0()	interrupt	1
{
	TH0=(65536-50000)/256;
	TL0=(65536-50000)%256;	
	bw=num/100;	  		   //分別取出百位、十位、各位
	shw=num%100/10;
	gw=num%10;
	if(P10==0)
	{
		num++;
		delay(350);	
		if(num==1000)
		{num=0;}
	}
	if(P11==0)
	{
		num--;
		delay(350);
		if(num==-1)
		{num=999;}
	}
		
		
	
}

void delay(uint z)
{
	uint x,y;
	for(x=z;x>0;x--)
		for(y=110;y>0;y--);
}