a.c

通过小键盘能够显示个值,从0~9,A~F

//7． C语言源程序 

#include <AT89X51.H> 

unsigned char code table[]={0x3f,0x06,0x5b,0x4f, 

                            0x66,0x6d,0x7d,0x07, 

                            0x7f,0x6f,0x77,0x7c, 

                            0x39,0x5e,0x79,0x71}; 

unsigned char temp; 

unsigned char key; 

unsigned char i,j; 

  

  

void main(void) 

{ P0=0x3f;

  P2=0xf7;
  while(1) 

    { 
    
      P3=0xff; 

      P3=0xef; 

      temp=P3; 

      temp=temp & 0x0f; 

      if (temp!=0x0f) 

        { 

          for(i=50;i>0;i--) 

          for(j=200;j>0;j--); 

          temp=P3; 

          temp=temp & 0x0f; 

          if (temp!=0x0f) 

            { 

              temp=P3; 

              temp=temp & 0x0f;              

              switch(temp) 

                { 

                  case 0x0e: 

                    key=12; 

                    break; 

                  case 0x0d: 

                    key=14; 

                    break; 

                  case 0x0b: 

                    key=14; 

                    break; 

                  case 0x07: 

                    key=15; 

                    break; 

                } 

              temp=P3; 

              P1_0=~P1_0; 

              P0=table[key]; 

              temp=temp & 0x0f;              

              while(temp!=0x0f) 

                { 

                  temp=P3; 

                  temp=temp & 0x0f;              

                } 

            } 

        } 

  

      P3=0xff; 

      P3=0xdf; 

      temp=P3; 

      temp=temp & 0x0f; 

      if (temp!=0x0f) 

        { 

          for(i=50;i>0;i--) 

          for(j=200;j>0;j--); 

          temp=P3; 

          temp=temp & 0x0f; 

          if (temp!=0x0f) 

            { 

              temp=P3; 

              temp=temp & 0x0f;              

              switch(temp) 

                { 

                  case 0x0e: 

                    key=8; 

                    break; 

                  case 0x0d: 

                    key=9; 

                    break; 

                  case 0x0b: 

                    key=10; 

                    break; 

                  case 0x07: 

                    key=11; 

                    break; 

                } 

              temp=P3; 

              P1_0=~P1_0; 

              P0=table[key]; 

              temp=temp & 0x0f;              

              while(temp!=0x0f) 

                { 

                  temp=P3; 

                  temp=temp & 0x0f;              

                } 

            } 

        } 

  

      P3=0xff; 

      P3=0xbf; 

      temp=P3; 

      temp=temp & 0x0f; 

      if (temp!=0x0f) 

        { 

          for(i=50;i>0;i--) 

          for(j=200;j>0;j--); 

          temp=P3; 

          temp=temp & 0x0f; 

          if (temp!=0x0f) 

            { 

              temp=P3; 

              temp=temp & 0x0f;              

              switch(temp) 

                { 

                  case 0x0e: 

                    key=4; 

                    break; 

                  case 0x0d: 

                    key=5; 

                    break; 

                  case 0x0b: 

                    key=6; 

                    break; 

                  case 0x07: 

                    key=7; 

                    break; 

                } 

              temp=P3; 

              P1_0=~P1_0; 

              P0=table[key]; 

              temp=temp & 0x0f;              

              while(temp!=0x0f) 

                { 

                  temp=P3; 

                  temp=temp & 0x0f;              

                } 

            } 

        } 

  

      P3=0xff; 

      P3=0x7f; 

      temp=P3; 

      temp=temp & 0x0f; 

      if (temp!=0x0f) 

        { 

          for(i=50;i>0;i--) 

          for(j=200;j>0;j--); 

          temp=P3; 

          temp=temp & 0x0f; 

          if (temp!=0x0f) 

            { 

              temp=P3; 

              temp=temp & 0x0f;              

              switch(temp) 

                { 

                  case 0x0e: 

                    key=0; 

                    break; 

                  case 0x0d: 

                    key=1; 

                    break; 

                  case 0x0b: 

                    key=2; 

                    break; 

                  case 0x07: 

                    key=3; 

                    break; 

                } 

              temp=P3; 

              P1_0=~P1_0; 

              P0=table[key]; 

              temp=temp & 0x0f;              

              while(temp!=0x0f) 

                { 

                  temp=P3; 

                  temp=temp & 0x0f;              

                } 

            } 

        } 

    } 
}