Arduino 矩陣鍵盤之控制

#define SL 4
#define G1 13
#define ROW 4
#define COL 2
#define NoTouch -1
const int scan[COL] = {10,11};
const int row[ROW] = {2,3,4,5};
const int keyScan[SL] = {6,7,8,9};
const int keyRow[SL] = {A0,A1,A2,A3};

void setup() {
      for (int i = 0;i<COL;i++) pinMode(scan[i], OUTPUT);
      for (int i = 0;i<SL;i++) {
            pinMode(keyScan[i], OUTPUT);
            pinMode(keyRow[i], INPUT);
      }
      for (int i = 0;i<ROW;i++) pinMode(row[i], OUTPUT);
      pinMode(G1, OUTPUT);
}

void loop() {
      int i;
      i=KeyCode();
      if(i!=NoTouch) prnLed(i); //有按才輸出
}

int KeyCode(){ //掃描鍵盤
      int i,j,k;
      for(i=0;i<SL;i++) {
            for(j=0;j<SL;j++)
                  digitalWrite(keyScan[j],(i!=j));
            for(k=0;k<SL;k++)
                  if(!digitalRead(keyRow[k])) return(k*SL+i);
      }
      return(NoTouch);
}

void prnLed(int x){
      int i,xi,xj,k;
      xi = x / SL;
      xj = x % SL;
      digitalWrite(G1,0);
      for(i=0,k=1;i<COL;i++, k<<=1)
            digitalWrite(scan[i],xi & k);
      for(i=0;i<ROW;i++, k<<=1)
            digitalWrite(row[i],(i==xj));
      digitalWrite(G1,1);
}