/******************************************************************************
                                4x4 矩陣鍵盤與4*4LED顯示
******************************************************************************/
#include"reg51.h"
#include "intrins.h"
#define uchar unsigned char
#define uint unsigned int
sbit p00=P0^0;
sbit p01=P0^1;
sbit p02=P0^2;
sbit p03=P0^3;
uchar key;
void keyscan(void)          //鍵盤掃描
{      uchar i,y;   uchar x=0;
     i=0xEF;   
     for(y=0;y<4;y++)
         {    P0=i;
	          if(p00==0)
		                 break;
		       key++;
		       if(p01==0)
		              break;
		      key++;
		        if(p02==0)
		             break;
		       key++;
		      if(p03==0)
		            break;
		        key++;
		   i=_crol_(i,1);//左移一次
        }
}
void display()   //把按下的鍵盤用LED顯示
{   
    switch(key)
        {  case  0 :    P3=0X1E;  break; 
  	       case  1 :    P3=0X1d;  break; 
		   case  2 :    P3=0X1b;  break; 
		   case  3:     P3=0X17;  break; 
		   case  4:     P3=0X2E;  break; 
		   case  5:     P3=0X2d;  break; 
		   case  6:     P3=0X2b;  break; 
		   case  7:     P3=0X27;  break; 
		   case  8:     P3=0X4E;  break; 
		   case  9:     P3=0X4d;  break; 
		   case  10:     P3=0X4b; break; 
		   case  11:     P3=0X47; break; 
		   case  12:     P3=0X8e; break; 
		   case  13:     P3=0X8d; break; 
		   case  14:     P3=0X8b; break; 
		   case  15 :    P3=0X87; break; 
		}
}
void main(void)
{   uchar i; 
     uchar z; 
            while(1)
		       {   P0=0X0F; 
			       i=P0;
			          if(i!=0x0F)
					       { keyscan();            //鍵盤掃描
						        for(;;)            /*判斷是否鍵以松*/
	                         	   {  P0=0x0f;
		                               z=P0;
		                               if(z==0x0f)
		                                break;                                 
		                             }
                                        display(); //調用LED顯示
                                        key=0;//重新開始計算鍵盤值              

						   }			   
			   }
}