jianpan.c

简单的LCD多级菜单显示

#include<reg52.h>
#include<jianpan.h>
 void  delay()
  {
  	char i;
	for(i=500;i>0;i--);
   }
 uchar keyscan()
{
    uchar scode,recode;
	static uchar m;
    P0=0xf0;
	if ((P0&0xf0)!=0xf0)
	 { 
	    delay();
	    if ((P0&0xf0)!=0xf0)		 
	     { 
		    scode=0xfe;
		    while((scode&0x10)!=0)  
		    { 
		       P0=scode;
		       if((P0&0xf0)!=0xf0)
		         { 
			        recode=(P0&0xf0)|0x0f;
					m=(~scode)+(~recode);
			        return (m);
			     }
		      else 
				  scode=(scode<<1)|0x01;
		    }
	     }

	  }
   return(0);
}