scankey1.c

这是几个实现键盘操作的程序

//矩阵式键盘单键输入应用，3×4
//P2口作为键盘的接口
void ScanKey1(void)
{
  unsigned char keytmp;
  //扫描第一行
  COLUMN1_PIN=0; //P2.4,scan line1 "0":active
  COLUMN2_PIN=1;
  COLUMN3_PIN=1;
  keytmp=~(P2)&0x0f;	//P2.0~P2.3
  switch(keytmp)
  {
  	case 1:
  		KeyData=KEY1;
  		break;
  	case 2:
  		KeyData=KEY2;
  		break;
  	case 4:
  		KeyData=KEY3;
  		break;
  		break;
  	case 8:
  		KeyData=KEY4;
  		break;
  	default:
  		break;
  }
    //扫描第二行
  COLUMN1_PIN=1;
  COLUMN2_PIN=0;	//P2.5,scan line2 "0":active
  COLUMN3_PIN=1;
  keytmp=~(P2)&0x0f;
  switch(keytmp)
  {
  	case 1:
  		KeyData=KEY5;
  		break;
  	case 2:
  		KeyData=KEY6;
  		break;
  	case 4:
  		KeyData=KEY7;
  		break;
  		break;
  	case 8:
  		KeyData=KEY8;
  		break;
  	default:
  		break;
  }
  
  	
  //扫描第三行
  COLUMN1_PIN=1;
  COLUMN2_PIN=1;	//P2.6,scan line3 "0":active
  COLUMN3_PIN=0;
  keytmp=~(P2)&0x0f;
  switch(keytmp)
  {
  	case 1:
  		KeyData=KEY9;
  		break;
  	case 2:
  		KeyData=KEY10;
  		break;
  	case 4:
  		KeyData=KEY11;
  		break;
  		break;
  	case 8:
  		KeyData=KEY12;
  		break;
  	default:
  		break;
  }
 COLUMN3_PIN=1;		//SCAN LINE3 NOT ACTIVE
}

//END FILE