keyboard.h

利用8255a扩展的lcd1602程序 希望喜欢

#include <at89x51.h>
#include <absacc.h>

#define A XBYTE[0x7efc]
#define B XBYTE[0x7efd]
#define C XBYTE[0x7efe]
#define Com XBYTE[0x7eff]
#define uchar unsigned char

void delay()
{
   int i,j;
   for(i=0;i<2;i++)
     for(j=0;j<200;j++);
}


void circel()
{
   unsigned char a,b,c,i;
    
	Com=0x81;
    C=0x0f;
    a=0xfe;
    
	for(i=0;i<200;i++)	
    {	
     b=a<<(8-1);
	 c=a>>1;
	 a=c|b;
	 A=a;
	 delay();
	}
    
   for(i=0;i<200;i++)
   {
	b=a>>(8-1);
	c=a<<1;
	a=c|b;
	A=a;
	delay();
	}
}


uchar  keyboard(void)
{
  uchar line,column;
  
  Com=0x88;
  
  C=0xf0;
  
  if((C&0xf0)!=0xf0)
  {
     delay();
     if((C&0xf0)!=0xf0)
     {
       line=0xfe;
       while((line&0x10)!=0)
       {
          C=line;
	  if((C&0xf0)!=0xf0)
	  {
	     column=(C&0xf0)|0x0f;
	     return((~line)+(~column));
	  }
	  else
	  line=(line<<1)|0x01;
       }
     }
  }
  return(0);
}