51单片机-60秒计时

#include"reg51.h"
#define uchar unsigned char
#define uint unsigned int

uchar tab[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; //led0-9

uchar data_l,data_h; //high bite and low bite 
uchar t,a; //count

void delay(uint k) //delay about 0.1ms 
{
	uint m,n;
	for(m=0;m<k;m++)
	{
		for(n=0;n<120;n++);
	}
}

void display (void) //display program
{
	p2=0x01;
	p0=tab[data_h];
	delay(1);
	p2=0x02;
	p0=tab[data_l];
	delay(1);
}

void timer0() interrupt 1 //50ms timing
{
	t++;
	th0=0x4c; //11.0592mhz initial value at high bits 
	tl0=0x00; //11.0592mhz initial value at low  bits 
}
void data_tim(void) //59s cuont 
{
	if(t==20)
	{
		a++;
		t=0;
		if(a==60)
		{
			a=0;
		}
	}
}

void data_in(void) //cut value 
{
	data_l=a%10;
	data_h=a/10;
}

void t0_init(void) //t0 initialization
{
	tmod=0x01; //t0 count model 1
	th0=0x4c;
	tl0=0x00;
	et0=1; //allow t0 break 
	tr0=1; //state t0
	ea=1; 
}
	
void main(void)
{
	a=0;
	t0_init();
	while(1)
	{
		data_tim();
		data_in();
		display();
	}
}