key.c

来自「C8051F020的PWM程序FYD12864显示」· C语言 代码 · 共 38 行

#include "020_Function.h"



void Delay()
  {
    unsigned int i;
	for(i=12000;i>0;i--);
  }

unsigned char Key_Scan()
 {
    unsigned char sccode,recode;
	P3=0xf0;
	if((P3&0xf0)!=0xf0)
	  {		    
		Delay();
		if((P3&0xf0)!=0xf0)
		  {
		    sccode=0xfe;
		    while((sccode&0x10)!=0)
			   {
			      P3=sccode;
			      if((P3&0xf0)!=0xf0)
				     {
					   recode=(P3&0xf0)|0x0f;
					   return((~sccode)+(~recode));
					  }
				 else
				   sccode=(sccode<<1)|0x01;
				}
		   }
	   }
	return(0);

 }