key.c

实现控制数码管

#include <reg52.h>
#include <intrins.h>
sbit STR=P0^6;
sbit CLK=P2^7;
sbit CDATA=P0^7;
void delay()
{
    unsigned int k=5;
    unsigned int l;
    while(k--)
    {
         l=6000;
         while(l--)
         {
            _nop_(); _nop_();
         }
    }
}
unsigned char anasys_key(unsigned char serial,unsigned char rate)
{
       switch (serial)
       {
        case 0x40:return(rate+0);
        case 0x20:return(rate+1);
        default:return(0xff);
       }
}
 void display(unsigned char buff)     /*将显示缓冲区的内容显示出来*/
     {
      unsigned char n;
      STR=0;      /*4094输出为三态,串改并*/
      CLK=0;
      n = 8;       /*一个数码管8段*/

   t:if( (buff & 0x80) == 0x80 )	{CDATA=1;}
      else   CDATA=0;
      CLK = 1;
      CLK = 0;
      buff <<= 1;
      if((--n)!=0)goto  t;
      STR = 1;
     }
void main(void)
{
   unsigned char data buff[6];
   unsigned char x,y;
   unsigned int j;
   P2=0xe0;
   x=P2;
   while(1)
   {
    if(x!=0xe0)
    {
     P2=0XFE;
     if((x=(P2&0X60))!=0X60){y=anasys_key(x,0);}
     P2=0XFD;
     if((x=(P2&0X60))!=0X60){y=anasys_key(x,2);}
     P2=0XFB;
     if((x=(P2&0X60))!=0X60){y=anasys_key(x,4);}
     P2=0XF7;
     if((x=(P2&0X60))!=0X60){y=anasys_key(x,6);}
     P2=0XEF;
     if((x=(P2&0X60))!=0X60){y=anasys_key(x,8);}
     buff[0]=y;
     for(j=1;j<6;j++)
         { buff[j]=0x7f;}
     for(j=0;j<6;j++)
       {
	  display(buff[j]);
       }
       STR=1;delay();
    }
    //else return(0xff);
   }
}