Sketch SETUP

Understanding the Arduino LCD Setup Code Line by Line

This short Arduino sketch sets up an LCD display so it’s ready to show text or data. Let’s go through each part step by step to see what’s happening.

🧩Code Example


void setup() // function
{

  lcd.init();

  lcd.backlight();
}

💡Line by Line Explanation

1️⃣ void setup()

This is a built-in Arduino function that runs once when your board starts up or is reset. It’s where you put all the code that prepares your hardware — like setting pin modes or initializing devices (in this case, the LCD).

2️⃣ { and }

These curly braces mark the beginning and end of the setup() function. Any instructions inside will run when the Arduino powers up.

3️⃣ lcd.init();

This command initializes the LCD screen. It tells the LiquidCrystal_I2C library to get the display ready for use — configuring the I2C connection and clearing any previous content.

Without this line, the LCD would not respond properly because it hasn’t been set up yet.

4️⃣ lcd.backlight();

This turns on the LCD’s built-in backlight, making the characters visible. If your LCD looks blank or dark, this is often the missing line!

You can later turn it off with lcd.noBacklight(); if needed to save power or dim the display.

📘Putting It Together

When your Arduino starts, it runs setup() once, which initializes the LCD and turns on its light. From there, you can start printing messages using lcd.print("Hello"); inside your loop() function or other parts of your sketch.

Tip: Always call lcd.init() before using any other LCD commands, and make sure your LCD address (for example, 0x27 or 0x3F) matches the one in your code.