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//矩阵键盘演示
#include<reg52.h>
#define uchar unsigned char
#define uint  unsigned int
unsigned char const dofly[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,
                                                    0x77,0x7c,0x39,0x5e,0x79,0x71};
uchar keyscan(void);//键盘扫描
void delay(uint i); 
void main()
{
 uchar key;
 P2=0x00;    
 while(1)
{
 key=keyscan();  //调用键盘扫描，
 switch(key)
 {
  case 0x7e:P0=dofly[0];break;//0 按下相应的键显示相对应的码值
  case 0x7d:P0=dofly[1];break;//1
  case 0x7b:P0=dofly[2];break;//2
  case 0x77:P0=dofly[3];break;//3
  case 0xbe:P0=dofly[4];break;//4
  case 0xbd:P0=dofly[5];break;//5
  case 0xbb:P0=dofly[6];break;//6
  case 0xb7:P0=dofly[7];break;//7
  case 0xde:P0=dofly[8];break;//8
  case 0xdd:P0=dofly[9];break;//9
  case 0xdb:P0=dofly[10];break;//a
  case 0xd7:P0=dofly[11];break;//b
  case 0xee:P0=dofly[12];break;//c
  case 0xed:P0=dofly[13];break;//d
  case 0xeb:P0=dofly[14];break;//e
  case 0xe7:P0=dofly[15];break;//f
 }
 }
}
uchar keyscan(void)  
{
 uchar cord_h,cord_l;
 P3=0x0f;          
 cord_h=P3&0x0f;   
 if(cord_h!=0x0f)  
 {
  delay(100);       
  if(cord_h!=0x0f)
  {
    cord_h=P3&0x0f;  
    P3=cord_h|0xf0;  
    cord_l=P3&0xf0;  
    return(cord_h+cord_l);
   }
  }return(0xff);    
}
void delay(uint i)  //延时函数
{
while(i--);
}