t11.c

51系列单片机在基本的开发例程

/* t11.c 按任意键显示该键字符 */
#include <reg51.h>
unsigned char led[16]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,
                        0x88,0x83,0xc6,0xa1,0x86,0x8e};	/* 字符 0-f 显示编码 */
unsigned char key,sccode,recode;


/* 键盘扫描码转换为字符显示码 */
unsigned char keyc(n)
unsigned char n;
{switch(n)
  {case 0x11:return(0);break;
   case 0x12:return(1);break;
   case 0x14:return(2);break;
   case 0x18:return(3);break;
   case 0x21:return(4);break;
   case 0x22:return(5);break;
   case 0x24:return(6);break;
   case 0x28:return(7);break;
   case 0x41:return(8);break;
   case 0x42:return(9);break;
   case 0x44:return(10);break;
   case 0x48:return(11);break;
   case 0x81:return(12);break;
   case 0x82:return(13);break;
   case 0x84:return(14);break;
   case 0x88:return(15);break;
  }
}

/* 延时 10ms */
void dlms(void)
{ unsigned int i;
  for(i=0;i<765;i++);}

/* 键盘扫描函数 */
unsigned char kbscan(void)
{ P1=0xf0;
  if((P1&0xf0)!=0xf0)
   { dlms();
     if((P1&0xf0)!=0xf0)
      { sccode=0xfe;
        while((sccode&0x10)!=0)
         { P1=sccode;
           if((P1&0xf0)!=0xf0)
            { recode=(P1&0xf0)|0x0f;
              return((~sccode)+(~recode));
            }
           else
            sccode=(sccode<<1)|0x01;
         }
      }
   }
  return(0);
}


void main(void)
{ while(1)
   { key=kbscan();
     if(key!=0)
      { P2=led[keyc(key)&0x0f];
      }
   }
}