jianpan.c

实现键盘码的读取

#include"reg51.h"
#define unchar unsigned char
void  delay();
unchar keyscan();
void   main()
{
   unchar key;
   P2=0x00;
   while (1)
  {
     key=keyscan();
     switch(key)
     {
	   case 0x18:P2=0x3f;break;
       case 0x14:P2=0x06;break;
	   case 0x12:P2=0x5b;break;
	   case 0x11:P2=0x4f;break;
	 
	   case 0x28:P2=0x66;break;
       case 0x24:P2=0x6d;break;
	   case 0x22:P2=0x7d;break;
	   case 0x21:P2=0x07;break;
	 
	   case 0x48:P2=0x7f;break;
       case 0x44:P2=0x6f;break;
	   case 0x42:P2=0x77;break;
	   case 0x41:P2=0x7c;break;

	   case 0x88:P2=0x39;break;
       case 0x84:P2=0x5e;break;
	   case 0x82:P2=0x79;break;
	   case 0x81:P2=0x71;break;
	   case 0x00:P2=0x76;break;
	   default: break;
	}
  }
} 

 void  delay()
  {
  	unchar i;
	for(i=500;i>0;i--);
   }
 unchar keyscan()
{
    unchar scode,recode;
	static unchar m;
    P1=0xf0;
	if ((P1&0xf0)!=0xf0)
	 { 
	    delay();
	    if ((P1&0xf0)!=0xf0)		 
	     { 
		    scode=0xfe;
		    while((scode&0x10)!=0)  
		    { 
		       P1=scode;
		       if((P1&0xf0)!=0xf0)
		         { 
			        recode=(P1&0xf0)|0x0f;
					m=(~scode)+(~recode);
			        return (m);
			     }
		      else 
				  scode=(scode<<1)|0x01;
		    }
	     }

	  }
  return(m);
}