关于单片机时钟中断问题，求大神看看代码哪里出了错。

#include<reg51.h>
sbit wei=P2^7;
sbit duan=P2^6;
unsigned char code talbe[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
void s(unsigned int i)
{
unsigned int m,n;
for(m=i;m>0;m--)
for(n=0;n<90;n++);
}
unsigned int l,q;
void main()
{
unsigned char num=l;
TMOD=0x01;
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
TCON=0X01;
TR0=1;
while(1){
if(num==16)num=0;
if(l==20){num++;
l=0;}
P0=talbe[num] ;
duan=1;
duan=0;
P0=0xfc;
wei=1;
wei=0;
s(1000);
}
}
void zqy() interrupt 1
{
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
l++;
}
数码管不会动