unsigned char  keybuf;			//鍵值緩存器
unsigned char p1keyj(void)		//判鍵子程序
    {unsigned char x;
     x=(P1IN&0X07);      		//P10--P12接有按鍵
     return(x);             		//有按鍵返回 非0
}  

unsigned char  keycode()		//哪個(gè)按鍵被按下，查鍵值子程序
	{
	unsigned char  x;
	if((P1IN&0x07)= = 1)		//是否第一個(gè)按鍵
		then x=0;
		else
		if((P1IN&0x07)= = 2)	//是否第二個(gè)按鍵
			then x=1;
			else
			if((P1IN&0x07)= = 4) //	是否第三個(gè)按鍵
			x=2;
	return(x);
	}

interrupt[PORT1_VECTOR] void port1key(void)
	{				//端口1的中斷服務(wù)程序
	while(p1keyj()!=0)
		{
		delay(500);		//延時(shí)消除抖動(dòng)
		while(p1keyj()!=0)
			{
			keybuf  =  keycode();//確信有按鍵按下，找按鍵得鍵值，送到全局變量keybuf
			while(p1keyj()= =0)  //等待按鍵松開
					;
			}
		}
}