Project 1 - Interfacing a 16*2 LCD with Arduino using I2C protocol

master 

#include
#include

// Initialize the LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
// Initialize the I2C communication
Wire.begin();

// Initialize the LCD
lcd.init();
lcd.backlight();

// Send a message to the Slave Arduino to display on the LCD
Wire.beginTransmission(9);
Wire.write("Hello from the Master Arduino!");
Wire.endTransmission();
}

void loop() {
// Nothing to do in the loop
}

slave

#include
#include

// Initialize the LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
// Initialize the I2C communication
Wire.begin(9);
Wire.onReceive(receiveEvent);

// Initialize the LCD
lcd.init();
lcd.backlight();
}

void loop() {
// Nothing to do in the loop
}

void receiveEvent(int length) {
// Read the message sent by the Master Arduino
char message[100];
int i = 0;
while(Wire.available()) {
message[i] = Wire.read();
i++;
}
message[i] = '\0';

// Display the message on the LCD
lcd.clear();
lcd.setCursor(0, 0);
lcd.print(message);
}

CD Pin	LCD Function	I2C Pin	Arduino Pin
1	GND	GND	GND
2	VCC	VCC	5V
3	V0
4	RS	SDA	A4 (SDA)
5	RW	GND	GND
6	EN	SCL	A5 (SCL)
7	D0
8	D1
9	D2
10	D3
11	D4	SDA	A4 (SDA)
12	D5	SDA	A4 (SDA)
13	D6	SDA	A4 (SDA)
14	D7	SDA	A4 (SDA)
15	LED+	VCC	5V
16	LED-	GND	GND