简单电子钟显示时数码管乱跳的问题

以下是程序，觉得写的也没什么问题啊。但仿真时，数码管乱显示！求解，什么地方出问题了呢？大虾们赐教啊
#include<reg51.h>
unsigned char t=0;
unsigned char second=0;
unsigned char tensec=0;
unsigned char minute=0;
unsigned char tenmin=0;
unsigned char hour=0;
unsigned char time[]={0xc0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
void display();
void delay();
main()
{
TMOD=0x01;
TH0=0X3C;
TL0=0XB0;
ET0=1;
EA=1;
TR0=1;
while(1)
display();
}
void timer0() interrupt 1
{
t++;
TH0=0X3C;
TL0=0XB0;
if(t==20)
{t=0;
second++;
if(second==10)
{
second=0;
tensec++;
if(tensec==6)
{
tensec=0;
minute++;
if(minute==10)
{
minute=0;
tenmin++;
if(tenmin==6)
{
tenmin=0;
hour++;
if(hour==24)
{
hour=0;
}
}
}
}
}
}
}
void display()
{
P0=time[second];
P2=0x01;
delay();
P0=time[tensec];
P2=0x02;
delay();
P0=time[minute];
P2=0x04;
delay();
P0=time[tenmin];
P2=0x08;
delay();
P0=time[hour%10];
P2=0x10;
delay();
P0=time[hour/10];
P2=0x20;
delay();
}
void delay()
{
int i;
for(i=0;i<100;i++);
}