key.h

矩阵键盘驱动程序

/*********************************************************/
/*****************keyboard  C51 driver*******************/
/*******************2006-8-11***************************/
/********************************************************/
//#include<reg51.h>
#define keyport P1
//---------------------------------------------------------
//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
//------------------------外部函数------------------------
    unsigned char key(void);
/*********************************************************/
//--------------------内部子程序--------------------------
void delay(void);//延时声明
//----------------------------------------------------
unsigned char key(void)
{	
	unsigned char keyv;	
	keyport=0xF0;         
	if((0xF0&keyport)!=0xF0)//检查是否有键按下
	{	
		delay();//延时去抖
		keyport=0xFE;//置第一行为零，检验每一列，下同
		switch(keyport)
		{
			case 0xEE:keyv=1;goto exit;
			case 0xDE:keyv=2;goto exit;
			case 0xBE:keyv=3;goto exit;
			case 0x7E:keyv=4;goto exit;
			default:break;
	    }
		keyport=0xFD;
		switch(keyport)
		{
			case 0xED:keyv=5;goto exit;
			case 0xDD:keyv=6;goto exit;
			case 0xBD:keyv=7;goto exit;
			case 0x7D:keyv=8;goto exit;
			default:break;
	    }
		keyport=0xFB;
		switch(keyport)
		{
			case 0xEB:keyv=9;goto exit;
			case 0xDB:keyv=10;goto exit;
			case 0xBB:keyv=11;goto exit;
			case 0x7B:keyv=12;goto exit;
			default:break;
	    }


		keyport=0xF7;
		switch(keyport)
		{
			case 0xE7:keyv=13;goto exit;
			case 0xD7:keyv=14;goto exit;
			case 0xB7:keyv=15;goto exit;
			case 0x77:keyv=16;goto exit;
			default:break;
	    }
	
	exit:
		return keyv;
	}
	else return(0); //没有键按下则置零
}
void delay(void) //延时程序
{
	unsigned char i;
	for(i=0;i<200;i++)
	{}
}