[嵌入式]外部中断实现keil代码

#include"reg51.h"
	sbit  ex =P3^2;
	unsigned char s[] = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F};
	unsigned char num=0;
	void initex()
	{
	IT0=1;
	EX0=1;
	EA=1;
	ex=1; 
	}
	void display()
	{
	P2= s [num];
	if(num==10)
	{
	num=0;
	}
	}
	void main()
	{

	initex();
	while(1)
	{
	display();
	}
	
	}
	void ex_isr()interrupt  0
	{
			 num++;
	}

元件：89c51 数码管 button(P3^2) G