// Pin configuration
#define RS 12   // Register Select pin (GP12)
#define RW 11   // Read/Write pin (GP11)
#define E 10    // Enable pin (GP10)
#define CONTRAST 15  // Contrast control pin (GP15)
#define DATA_PINS_START 0 // Data pins start at GP0-GP7

// Send a command to the LCD
void sendCommand(uint8_t command) {
  digitalWrite(RS, LOW); // RS = 0 for command
  digitalWrite(RW, LOW); // RW = 0 for write
  sendByte(command);
}

// Send a data byte to the LCD
void sendData(uint8_t data) {
  digitalWrite(RS, HIGH); // RS = 1 for data
  digitalWrite(RW, LOW);  // RW = 0 for write
  sendByte(data);
}

// Send a byte to the LCD (for commands or data)
void sendByte(uint8_t value) {
  // Set the data pins
  for (int i = 0; i < 8; i++) {
    digitalWrite(DATA_PINS_START + i, (value >> i) & 0x01);
  }

  // Toggle the enable pin to send the data/command
  digitalWrite(E, HIGH);
  delayMicroseconds(1); // Short delay
  digitalWrite(E, LOW);
  delayMicroseconds(100); // Allow time for the command to be processed
}

// Initialize the LCD
void lcdInit() {
  pinMode(RS, OUTPUT);
  pinMode(RW, OUTPUT);
  pinMode(E, OUTPUT);
  for (int i = 0; i < 8; i++) {
    pinMode(DATA_PINS_START + i, OUTPUT);
  }
  pinMode(CONTRAST, OUTPUT);
  analogWrite(CONTRAST, 128); // Set a default contrast level (0-255)

  delay(50); // Wait for the LCD to power up

  // Initialize LCD in 8-bit mode
  sendCommand(0x38); // Function set: 8-bit, 2 lines, 5x8 dots
  sendCommand(0x0C); // Display ON, Cursor OFF, Blink OFF
  sendCommand(0x01); // Clear display
  delay(2);          // Wait for the clear command to complete
  sendCommand(0x06); // Entry mode set: Increment cursor, no shift
}

// Write a string to the LCD
void lcdWriteString(const char *str) {
  while (*str) {
    sendData(*str++);
  }
}

// Set the cursor to a specific position (col: 0-19, row: 0-1)
void lcdSetCursor(uint8_t col, uint8_t row) {
  uint8_t rowOffsets[] = {0x00, 0x40};
  sendCommand(0x80 | (col + rowOffsets[row])); // Set DDRAM address
}

void setup() {
  lcdInit();
  lcdSetCursor(0, 0); // Start at the beginning of the first line
  lcdWriteString("Hello, 20x12 LCD!");
}

void loop() {
  // In this example, the loop does nothing.
}