仿真结果是红灯会亮30秒，黄灯5秒，绿灯20秒，每个led在最后5秒都会闪烁。按下中断按键是直接全灭（包括倒数数码管），按复位键即可重新开机。

代码

#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit red=P0^0;	
sbit yellow=P0^1;	
sbit green=P0^2;	
uint x,y;
uchar i;
uchar count;
uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
/*ÑÓ³Ùº¯Êý*/
void delay(uint time)
{
	for(x=time;x>0;x--)
	{
	for(y=110;y>0;y--);
	}
}

void zhongduan() interrupt 0
{
red=1;
yellow=1;
green=1;
P1=0x00;
P2=0x00;
while(1);
}


void daoshu()
{
	
	red=0;
	yellow=1;
	green=1;
	count=30;
	for(i=25;i>0;i--)
	{
		
		count=count-1;
		P1=table[count%10];
		P2=table[count/10];
		delay(1000);
	};
	for(i=5;i>0;i--)
		{
			count=count-1;
		P1=table[count%10];
		P2=table[count/10];
			red=1;
			delay(500);
			red=0;
			delay(500);
		}
	;
	
	
	red=1;
	yellow=0;
	green=1;
	count=5;
	for(i=5;i>0;i--)
		{
			count=count-1;
		P1=table[count%10];
		P2=table[count/10];
			yellow=1;
			delay(500);
			yellow=0;
			delay(500);
		}
	;
	
	red=1;
	yellow=1;
	green=0;
	count=20;
	for(i=15;i>0;i--)
	{
	
		count=count-1;
		P1=table[count%10];
		P2=table[count/10];
		delay(1000);
	};
	for(i=5;i>0;i--)
		{
			count=count-1;
		P1=table[count%10];
		P2=table[count/10];
			green=1;
			delay(500);
			green=0;
			delay(500);
		}
}

void main()
{
IT0=1;
	EX0=1;
	EA=1;
while(1)
{
  daoshu();
}
	
}