Logo
HomeArduinoRaspberry PiESP32JetsonIoT

Interfacing of 16x2 LCD (HD44780) with Arduino

16x2 LCD Display (HD44780)

A 16x2 LCD (Liquid Crystal Display) is a commonly used display module in electronics projects. It can display 16 characters per line on 2 lines and is perfect for showing messages, sensor values, or debug information in real-time.

Working Principle of 16x2 LCD

The 16x2 LCD operates using a controller (usually HD44780) which communicates with Arduino over a parallel interface. It uses ASCII values to display characters and allows cursor control, scrolling, and custom characters.

Wiring 16x2 LCD to Arduino

LCD Pinout

  • VSS: Connect to GND
  • VDD: Connect to +5V
  • VO: Contrast control (use potentiometer)
  • RS: Register Select pin
  • RW: Read/Write mode (GND for write mode)
  • E: Enable pin to latch data
  • D0-D7: Data pins (only D4-D7 are used in 4-bit mode)
  • A: Anode for backlight (connect to +5V via resistor)
  • K: Cathode for backlight (connect to GND)

How Does the 16x2 LCD Work?

The 16x2 LCD operates using a controller (usually HD44780) which communicates with Arduino over a parallel interface. It uses ASCII values to display characters and allows cursor control, scrolling, and custom characters.

Experiment of Code

The LCD uses a series of commands and data bytes to control what is shown on screen. Commands control settings like cursor position or clearing the display, while data writes characters to the screen buffer.

Algorithm

  1. Initialize Components

    • Connect LCD to Arduino as per the wiring diagram.
    • Use a potentiometer to control the contrast on VO pin.
    • Power the backlight using pins A and K with appropriate resistors.

  2. Write the Code

    • Include the LiquidCrystal library.
    • Create an LCD object with the connected pins.
    • Initialize the display with lcd.begin(16, 2).
    • Use lcd.print() to display text on screen.

  3. Display Dynamic Values

    • Update the display in loop() to show changing values.
    • Use lcd.setCursor() to position text.
    • Clear the screen if needed with lcd.clear().

  4. Test the Setup

    • Upload the sketch to your Arduino.
    • Ensure text appears on the display.
    • Adjust the contrast using the potentiometer if necessary.

Arduino Code

1#include <LiquidCrystal.h>
2
3// RS, E, D4, D5, D6, D7
4LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
5
6void setup() {
7  lcd.begin(16, 2); // 16 columns, 2 rows
8  lcd.print("Hello, World!");
9}
10
11void loop() {
12  lcd.setCursor(0, 1); // Second row
13  lcd.print("LCD 16x2 Ready");
14  delay(1000);
15}
16

Conclusion

Interfacing a 16x2 LCD with Arduino is an essential step in learning how to visualize data in embedded systems. With simple wiring and the LiquidCrystal library, you can create interactive and informative displays for your Arduino projects.