// include the library code:
#include <LiquidCrystal.h>
 

// Pin definitions
#define RS 19
#define E  23
#define D4 18
#define D5 17
#define D6 16
#define D7 15

#define delayTime 300

// Small delay helpers
void pulseEnable() {
  digitalWrite(E, LOW);
  delayMicroseconds(1);

  digitalWrite(E, HIGH);
  delayMicroseconds(1);  // Enable pulse must be >450ns

  digitalWrite(E, LOW);
  delayMicroseconds(100); // Command needs time to process
}

void write4Bits(uint8_t nibble) {
  digitalWrite(D4, (nibble >> 0) & 1);
  digitalWrite(D5, (nibble >> 1) & 1);
  digitalWrite(D6, (nibble >> 2) & 1);
  digitalWrite(D7, (nibble >> 3) & 1);

  pulseEnable();
}

void sendByte(uint8_t value, bool isData) {
  digitalWrite(RS, isData ? HIGH : LOW);

  // Send high nibble
  write4Bits(value >> 4);

  // Send low nibble
  write4Bits(value & 0x0F);
}

void sendCommand(uint8_t cmd) {
  sendByte(cmd, false);
}

void sendChar(char c) {
  sendByte(c, true);
}

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(19, 23, 18, 17, 16, 15);
 
void setup() {
  delay(50); // Wait for LCD to power up

  digitalWrite(RS, LOW);
  digitalWrite(E, LOW);

  // Initialize into 4-bit mode
  write4Bits(0x03);
  delay(5);

  write4Bits(0x03);
  delayMicroseconds(150);

  write4Bits(0x03);
  write4Bits(0x02); // Set 4-bit mode

  // Function set: 4-bit, 2 line, 5x8 font
  sendCommand(0x28);

  // Display ON, cursor OFF
  sendCommand(0x0C);

  // Clear display
  sendCommand(0x01);
  delay(2);

  // Entry mode set (increment cursor)
  sendCommand(0x06);
}
 
void loop() {
  sendCommand(0x01); // clear display
  delay(2);          // IMPORTANT (needs ~2ms)
  sendCommand(0x90);
  sendChar('H');
  sendChar('E');
  sendChar('L');
  sendChar('L');
  sendChar('O');

  sendChar(' ');

  sendChar('W');
  sendChar('O');
  sendChar('R');
  sendChar('L');
  sendChar('D');
  sendChar('!');
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);
  sendCommand(0x18);
  delay(delayTime);


sendCommand(0xD0); // now guaranteed correct position
sendChar('H');
delay(delayTime);
sendChar('o');
delay(delayTime);
sendChar('o');
delay(delayTime);
sendChar('k');
delay(delayTime);

sendChar(' ');
delay(delayTime/2);

sendChar('\'');
delay(delayTime);

sendChar('E');
delay(delayTime);

sendChar('m');
delay(delayTime);

sendChar('!');
delay(delayTime);

sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
sendCommand(0x18);
delay(delayTime);
}