Simple Arduino Mega sketch for reading a CP500 keyboard

cp500.ino

const char* keysupp = "@ABCDEFGHIJKLMNOPQRSTUVWXYZ     0!\"#$%&'()*+<=>?";
const char* keysdwn = "@abcdefghijklmnopqrstuvwxyz     0123456789:;,-./";

const byte colCount = 8;
const byte colStart = 22;
const byte rowStart = colStart + colCount;

boolean pressed;
boolean held;
boolean shift;

void setup() {
  for(int i = 0; i < 8; i++) {
    pinMode(i+colStart, OUTPUT);
    digitalWrite(i+rowStart, HIGH);
    pinMode(i+rowStart, INPUT_PULLUP);
  }
  Serial.begin(9600);
}

void loop() {
  pressed = false;
  for(int i = 0; i < 8; i++) {
    byte col = i + colStart;
    digitalWrite(col, LOW);
    delay(1);
    for(int j = 0; j < 8; j++) {
      if(digitalRead(j + rowStart) == LOW) {
        pressed = true;
        if(!held) {
          if(i == 6) {
            if(j == 0) Serial.println();
            if(j == 7) Serial.print(" ");
          } else if(i == 7) {
            shift = !shift;
          } else {
            if(shift) Serial.print(keysupp[i*colCount+j]);
            else Serial.print(keysdwn[i*colCount+j]);
          }
        }
      }
    }
    digitalWrite(col, HIGH);
  }
  held = pressed;
}