4x4keybard.h

基于51的lcd1602数字时钟 可调解时间 自动调节星期

/* 4x4键盘扫描*/
#include <reg52.h>
code char key_code[]={0XEE,0XDE,0XBE,0X7E,0XED,0XDD,0XBD,0X7D,
                      0XEB,0XDB,0XBB,0X7B,0XE7,0XD7,0XB7,0x77};
code ksp[4]={0xFE,0xFD,0xFB,0xF7};
void delay1(void) 
 {                   /* 时间延迟函数 */
  unsigned char i,j;                  
     for (i=0;i<5;i++)
          for(j=0;j<255;j++)
          ;
  }
char keypad_scan()
{
    char key,i;
    P3=0xF0;
    while (P3!=0xF0);
      do{
	       for(i=0;i<4;i++)
	       {         
	           P3=ksp[i];
	           if(P3!=ksp[i])
	           {
	              delay1();
	              key=P3;
	              if(key!=ksp[i])
	              {
	                  return(key);
	              }
	           }
           }
        } while(1);
}
// 检查是否有按键按下
char gotkey(void)
{
     char temp,i;
     temp=keypad_scan();
     for (i=0;i<16;i++) 
	 {
       if(temp==key_code[i]) return(i);
      }
     //return(16);
}