期中考试秒表计时器

#include<reg52.h>
#define LED P0
unsigned int i = 0;
unsigned int j =0;
sbit KEY1 = P1^0;     //暂停，开始按钮
sbit KEY2 = P1^2;       //复位按键
unsigned char NUM[]= {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,                    0x80,0x90,0x88,0x83,0xA7,0xA1,0x86,0x8E}; //?????0-f
void INT_T0(void)
{
    TMOD = 0X01;   //打开定时器0 ，使用模式1定时
    TH0 = 0XFC;
    TL0    = 0X18;     //初始值
    EA = 1;     //打开总开关
    ET0 = 1;     //打开中断T0开关
}
void main(void)
{    
    INT_T0();
    TR0 = 0;      //定时功能关闭
    LED = NUM[0];
    while(1)
    {            
        if(KEY1 == 0)
        {
            TR0= 1 ;  //判断按键按下  ，则打开定时计时功能
        }
        else
        {
            TR0=0;       //判断按键松开，则断开计时功能
        }
        if(KEY2 == 0)
        {
             break;        //跳出循环，计时归零
        }    
    }
}
 
void time0(void) interrupt 1 
{
    TH0 = 0XFC;
    TL0    = 0X18; //初始值
    if(i < 1000)
    {
        i++;
    }
    else
    {
         LED= NUM[j]    ;
        if(j < 16)
        {
         j++;
        }
        else
        {
             j=0;
        }
        i = 0;
    }
    
}