lcdOK.ino

// Define LCD pin connections
const int rs = 8;
const int en = 9;
const int db4 = 13;
const int db5 = 12;
const int db6 = 11;
const int db7 = 10;

void pulseEnable() {
  digitalWrite(en, LOW);
  delayMicroseconds(1);
  digitalWrite(en, HIGH);
  delayMicroseconds(1);    // Enable pulse must be >450ns
  digitalWrite(en, LOW);
  delayMicroseconds(100);   // Commands need > 37us to settle
}

void sendNibble(int value) {
  digitalWrite(db4, (value >> 0) & 0x01);
  digitalWrite(db5, (value >> 1) & 0x01);
  digitalWrite(db6, (value >> 2) & 0x01);
  digitalWrite(db7, (value >> 3) & 0x01);
  pulseEnable();
}

void sendByte(int value, int mode) {
  digitalWrite(rs, mode);
  sendNibble(value >> 4);
  sendNibble(value & 0x0F);
}
void initLCD() {
  pinMode(rs, OUTPUT);
  pinMode(en, OUTPUT);
  pinMode(db4, OUTPUT);
  pinMode(db5, OUTPUT);
  pinMode(db6, OUTPUT);
  pinMode(db7, OUTPUT);

  delay(50);
  sendNibble(0x03);
  delay(5);
  sendNibble(0x03);
  delayMicroseconds(150);
  sendNibble(0x03);
  sendNibble(0x02); // Switch to 4-bit mode

  sendByte(0x28, 0); // 4-bit mode, 2 lines, 5x8 dots
  sendByte(0x0C, 0); // Display on, cursor off, blink off
  sendByte(0x01, 0); // Clear display
  delay(2); // Clear command requires a delay
  sendByte(0x06, 0); // Increment cursor
}

void setup() {
  initLCD();
  sendByte(0x80, 0); // Set cursor to the beginning of the first line
  sendByte('G', 1);  // Send 'H'
  sendByte('R', 1);
  sendByte('E', 1);
  sendByte('E', 1);
  sendByte('N', 1);
  sendByte(' ', 1);
  sendByte('H', 1);
  sendByte('A', 1);
  sendByte('C', 1);
  sendByte('K', 1);
  sendByte('E', 1);
  sendByte('R', 1);
  sendByte('S', 1);
}

void loop() {
  // Nothing to do here
}