键盘程序.c

单片机＋4*4键盘

//出错情况：CASE语句不能正确选择其中一种情形//
#include <reg51.h> // 包含头文件 
#include <absacc.h> 
#include <intrins.h> 
#include<math.h>
#define unchar unsigned char
#define unint unsigned int

unint keyscan(void);
void display(unint dat);

void display(unchar dat)
 {
  unchar code table[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x77,0x7c,0x39,0x5e,0x79,0x71};
  P0=table[dat];                       
 }

unint keyscan(void)
{
 unchar result,dat,lie,hang,i,temp;
 hang=0xfe;
 dat=1;
 for(i=0;i<=3;i++)
    {P3=hang;
	 temp=P3;
	 if(hang!=temp)
	   {
	   lie=P3||0x0f;      //取出列值
	   switch(lie)
	     {case 0xef:result=dat;break;  //第一列
		  case 0xdf:result=dat+1;break;//第二列
		  case 0xbf:result=dat+2;break;//第三列
		  default:	result=14;break;   //出错情况
		  }
       }
      hang=~((~hang)<<1);
      dat=dat+3;
    }	 
	return(result);
}					

main()
{unchar x;
 while(1)							  
 {
 x=keyscan();
 display(x);
 }
}