keyboard.c

4*4键盘扫描程序

#include "mega16.h"
#include "delay.h" 
#include "avryejing.c"
#define   scanport_dir  DDRD
#define   scanport_out  PORTD  
#define   scanport_in   PIND

unsigned char keydata=0;
//unsigned  char ledcode[16]={0xc0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E};  
unsigned  char lcdcode[18]={16,17,18,19,20,21,22,23,24,25,33,34,35,36,37,38,39,40};

unsigned char key_read(void)
{ unsigned char i;  
  scanport_dir = 0xFF;/*获取列地址*/   //出 出 出 出 出 出 出 出
  scanport_out = 0x0F;                 // 0  0  0  0  1  1  1  1
  scanport_dir = 0xF0;                 //出 出 出 出 入 入 入 入
  i = scanport_in;                     // 0  0  0  1  1  1  1  1
  
  scanport_dir = 0xFF;/*获取行地址*/ 
  scanport_out = 0xF0;
  scanport_dir = 0x0F; 
  i &= scanport_in;  
  
  scanport_dir = 0x00;/*输出复位*/ 
  scanport_out = 0xFF;  
  
  switch (i) 
      {/*将按键码转换成键值*/  
        case  0x11: return 0; break; 
        case  0x21: return 1; break; 
        case  0x41: return 2; break; 
        case  0x81: return 3; break; 
        case  0x12: return 4; break; 
        case  0x22: return 5; break; 
        case  0x42: return 6; break; 
        case  0x82: return 7; break; 
        case  0x14: return 8; break; 
        case  0x24: return 9; break; 
        case  0x44: return 10;break;  
        case  0x84: return 11;break;  
        case  0x18: return 12;break;  
        case  0x28: return 13;break;  
        case  0x48: return 14;break;  
        case  0x88: return 15;break;
        case  0x00: return 16;break;
        default : return 17;  
      } 
  }
  

  /*按键获取函数 获取按键信号，其中包含有状态记录及按键去颤抖。
   有正确按键按下返回相应按键值 无正确按键按下返回"0xFF"*/
  unsigned char get_key(void)
  { unsigned char i; 
    unsigned char j;    /*按键记录*/ 
    i = key_read(); 
    if (i == 16)                /*无有效按键按下*/  
    {
     j = 0x00;                  /*清除按键记录*/  
      return 0xFF;              /*程序退出*/  
     }
    if (j== 0x00)
    {               /*为新按键*/  
       j = i;
       delay_ms(10 );
       i = key_read(); 
       if(i == j) 
       {   return i;   }
       else return 0xFF;  
     } 
   
   }
   void main(void)
   {
    //DDRA=0XFF;
    //DDRC=0XFF;
    //DDRD=0XFF;
    DDRA=0xff;
    PORTA=0xff;
 #asm("cli");
  
   delay_ms(1000);               //初始化液晶
   resetlcd();
   delay_ms(500);                     
    while(1)
    {
     keydata=get_key();
     if(keydata!=0xFF)
     {
       //PORTA=ledcode[keydata];
       word(0,0,lcdcode[keydata]);
       delay_ms(300);
     } 
    }
   }