const int rs = 12;
const int en = 11;
const int d4 = 10;
const int d5 = 9;
const int d6 = 8;
const int d7 = 7;

void pulseEnable() {
  digitalWrite(en, HIGH);
  delayMicroseconds(1);
  digitalWrite(en, LOW);
  delayMicroseconds(50);
}

void sendCommand(byte command) {
  digitalWrite(rs, LOW);
  digitalWrite(d4, (command >> 4) & 1);
  digitalWrite(d5, (command >> 5) & 1);
  digitalWrite(d6, (command >> 6) & 1);
  digitalWrite(d7, (command >> 7) & 1);
  pulseEnable();

  digitalWrite(d4, command & 1);
  digitalWrite(d5, (command >> 1) & 1);
  digitalWrite(d6, (command >> 2) & 1);
  digitalWrite(d7, (command >> 3) & 1);
  pulseEnable();
}

void sendData(byte data) {
  digitalWrite(rs, HIGH);
  digitalWrite(d4, (data >> 4) & 1);
  digitalWrite(d5, (data >> 5) & 1);
  digitalWrite(d6, (data >> 6) & 1);
  digitalWrite(d7, (data >> 7) & 1);
  pulseEnable();

  digitalWrite(d4, data & 1);
  digitalWrite(d5, (data >> 1) & 1);
  digitalWrite(d6, (data >> 2) & 1);
  digitalWrite(d7, (data >> 3) & 1);
  pulseEnable();
}

void printText(const char* text, int row, int col) {
  int position = col + (row == 1 ? 0x40 : 0x00);
  sendCommand(0x80 | position); // Set DDRAM address
  for (int i = 0; text[i] != '\0'; ++i) {
    sendData(text[i]);
  }
}

void setup() {
  pinMode(rs, OUTPUT);
  pinMode(en, OUTPUT);
  pinMode(d4, OUTPUT);
  pinMode(d5, OUTPUT);
  pinMode(d6, OUTPUT);
  pinMode(d7, OUTPUT);

  sendCommand(0x33);
  sendCommand(0x32);
  sendCommand(0x28);
  sendCommand(0x0C);
  sendCommand(0x06);
  sendCommand(0x01);

  printText("Hello", 0, 0);
  printText("World", 1, 0);
}

void loop() {
  
}