#define ROW P2OUT       //矩阵键盘的行宏定义
#define COL P2IN        //矩阵键盘的列宏定义
#define DPYOUT P3OUT    //数码管输出口宏定义
unsigned char keyval;   //键值

//共“阳”极数码管的码表         
unsigned char LED7CA[] ={~0x3F,~0x06,~0x5B,~0x4F,~0x66,~0x6D,~0x7D,
               ~0x07,~0x7F,~0x6F,~0x77,~0x7C,~0x39,~0x5E,~0x79,~0x71,0xff};

unsigned char keyscan()
{
  int i=0;
  unsigned char key=0;
  ROW = 0x8f;        //先置三行输出低电平
  if((COL & 0x0f)!= 0x0f) //是否有按键
  {
    do i++;
    while(i<3000);        //消抖动延时
    ROW = 0xbf;           //扫描第一行
    if((COL & 0x0f)== 0x0f)
    { ROW = 0xdf;         //扫描第二行
      if((COL & 0x0f)== 0x0f)
      { ROW = 0xef;       //扫描第三行
        if((COL & 0x0f)== 0x0f)
          key = 15;
        else key = ~((ROW & 0XF0)|(COL & 0X0F));
      }
      else key = ~((ROW & 0XF0)|(COL & 0X0F));
    }
    else key = ~((ROW & 0XF0)|(COL & 0X0F));
    if(key != 15)
     switch(key)      //获取有效地键值
     { case 0x48: key=0; break;
       case 0x44: key=1; break;
       case 0x42: key=2; break;
       case 0x41: key=3; break;
       case 0x28: key=4; break;
       case 0x24: key=5; break;
       case 0x22: key=6; break;
       case 0x21: key=7; break;
       case 0x18: key=8; break;
       case 0x14: key=9; break;
       case 0x12: key=10;break;
       case 0x11: key=11;break;
       default: key=15;
     }
  }
  else key = 15;
  keyval=key;
  return key;
}

void main( void )
{
  // Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
  P3DIR |= 0xff;
  P3OUT = 0xff;             //共阳极数码管输出口初始化
  P2DIR |= BIT4 +BIT5+BIT6; //先配置矩阵键盘的行（输出）
      //P2.6 第一行，P2.5 第二行，P2.4 第三行
      //P2.3 第一列，P2.2 第二列，P2.1 第三列，P2.0 第四列
  keyval=16;
  while(1)
  { keyscan();
    if(keyval != 15 && keyval<17)
      DPYOUT = LED7CA[keyval];//数码管显示键值
  }
}