课程设计：矩阵键盘（c51，使用扫描法实现）

//这种方法是用只用P3口的前高四位来比较，看改变了么(由于比较仓促，没有proteus仿真，不过这是个比较经典的方法，网上有很多这个代码，源自郭天祥的视频和书籍)

#include

#define uchar unsigned char

#define uint unsigned int

sbit wela=P2^7;

sbit dula=P2^6;

uchar num,num1;

unsigned char code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,

0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};

void delay(uint xms)

{

       uint x,y;

       for(x=xms;x>0;x--)

              for(y=111;y>0;y--);      

}

void display(uchar num)

{    

       dula=1;

       P1=table[num];

       dula=0;

//     delay(10);

}

void matrixkeyscan()

{

       uchar temp,key;

       P3=0xfe; //第一行

       temp=P3;

       temp=temp&0xf0;                                                         

       if(temp!=0xf0)

       {

              delay(10);

              temp=P3;

              temp=temp&0xf0;

              if(temp!=0xf0)

              {    

                     temp=P3;

                     switch(temp)

                     {

                            case 0xee:

                                          key=0;

                                          break;

                            case 0xde:

                                          key=1;

                                          break;

                            case 0xbe:

                                          key=2;

                                          break;

                            case 0x7e:

                                          key=3;

                                          break;

                     }

                     while(temp!=0xf0)

                     {

                            temp=P3;

                            temp=temp&0xf0;

                     }

                     display(key);

              }

       }

       P3=0xfd; //第二行

       temp=P3;

       temp=temp&0xf0;                                                         

       if(temp!=0xf0)

       {

              delay(10);

              temp=P3;

              temp=temp&0xf0;

              if(temp!=0xf0)

              {    

                     temp=P3;

                     switch(temp)

                     {

                            case 0xed:

                                          key=4;

                                          break;

                            case 0xdd:

                                          key=5;

                                          break;

                            case 0xbd:

                                          key=6;

                                          break;

                            case 0x7d:

                                          key=7;

                                          break;

                     }

                     while(temp!=0xf0)

                     {

                            temp=P3;

                            temp=temp&0xf0;

                     }

                     display(key);

              }

       }

       P3=0xfb;               //第三行

       temp=P3;

       temp=temp&0xf0;                                                         

       if(temp!=0xf0)

       {

              delay(10);

              temp=P3;

              temp=temp&0xf0;

              if(temp!=0xf0)

              {    

                     temp=P3;

                     switch(temp)

                     {

                            case 0xeb:

                                          key=8;

                                          break;

                            case 0xdb:

                                          key=9;

                                          break;

                            case 0xbb:

                                          key=10;

                                          break;

                            case 0x7b:

                                          key=11;

                                          break;

                     }

                     while(temp!=0xf0)

                     {

                            temp=P3;

                            temp=temp&0xf0;

                     }

                     display(key);

              }

       }

       P3=0xf7;          //第四行

       temp=P3;

       temp=temp&0xf0;                                                         

       if(temp!=0xf0)

       {

              delay(10);

              temp=P3;

              temp=temp&0xf0;

              if(temp!=0xf0)

              {    

                     temp=P3;

                     switch(temp)

                     {

                            case 0xe7:

                                          key=12;

                                          break;

                            case 0xd7:

                                          key=13;

                                          break;

                            case 0xb7:

                                          key=14;

                                          break;

                            case 0x77:

                                          key=15;

                                          break;

                     }

                     while(temp!=0xf0)

                     {

                            temp=P3;

                            temp=temp&0xf0;

                     }

                     display(key);

              }

       }                  

}

void main()

{

       dula=0;

       wela=1;

       P1=0x00;

       wela=0;

       //dula=0;

       while(1)

       {     //dula=0;

               matrixkeyscan();

       }

}