The LCD 20x4 is a Liquid Crystal Display capable of displaying 20 characters per line across 4 lines. It is widely used in embedded systems and microcontroller projects for presenting textual information such as sensor readings, system status, or user instructions. This display module is based on the HD44780 controller, making it compatible with most microcontrollers, including Arduino, Raspberry Pi, and other development boards.
This circuit consists of an Arduino UNO microcontroller connected to a 20x4 I2C LCD display. The Arduino provides power and communicates with the LCD via I2C protocol to display static text messages across its four rows.
Open Project in Cirkit Designer
This circuit interfaces a 20x4 I2C LCD display with a power source and an I2C communication bus. The LCD is powered by a 4.2V supply from a connector and communicates via I2C through another connector, which provides the SCL and SDA lines as well as ground.
Open Project in Cirkit Designer
This circuit features an Arduino Nano microcontroller interfaced with a 20x4 I2C LCD panel for display purposes. The LCD panel is powered by a 5V AC-DC power supply unit, and the Arduino Nano communicates with the LCD via I2C protocol using its A5 (SDA) and A1 (SCL) pins.
Open Project in Cirkit Designer
This circuit connects an ESP32 microcontroller to a 20x4 LCD display with an I2C interface. The ESP32 powers the LCD and communicates with it using the I2C protocol, with D21 and D22 pins serving as the data (SDA) and clock (SCL) lines, respectively. The circuit is designed to display information or user interface elements controlled by the ESP32.
Open Project in Cirkit DesignerThe following table outlines the key technical details of the LCD 20x4 module:
| Parameter | Specification |
|---|---|
| Display Type | 20x4 Character LCD |
| Controller | HD44780 or compatible |
| Operating Voltage | 4.7V to 5.3V |
| Operating Current | 1.5mA (without backlight) |
| Backlight Voltage | 4.2V to 4.6V |
| Backlight Current | 120mA (typical) |
| Character Size | 5x8 dot matrix |
| Interface Type | Parallel (4-bit or 8-bit mode) |
| Operating Temperature | -20°C to 70°C |
| Dimensions | 98mm x 60mm x 12mm |
The LCD 20x4 module typically has 16 pins. The table below describes each pin:
| Pin Number | Pin Name | Description |
|---|---|---|
| 1 | VSS | Ground (0V) |
| 2 | VDD | Power supply (4.7V to 5.3V) |
| 3 | VO | Contrast adjustment (connect to a potentiometer) |
| 4 | RS | Register Select (0: Command, 1: Data) |
| 5 | RW | Read/Write (0: Write, 1: Read) |
| 6 | E | Enable signal (starts data read/write) |
| 7 | D0 | Data bit 0 (used in 8-bit mode only) |
| 8 | D1 | Data bit 1 (used in 8-bit mode only) |
| 9 | D2 | Data bit 2 (used in 8-bit mode only) |
| 10 | D3 | Data bit 3 (used in 8-bit mode only) |
| 11 | D4 | Data bit 4 (used in 4-bit or 8-bit mode) |
| 12 | D5 | Data bit 5 (used in 4-bit or 8-bit mode) |
| 13 | D6 | Data bit 6 (used in 4-bit or 8-bit mode) |
| 14 | D7 | Data bit 7 (used in 4-bit or 8-bit mode) |
| 15 | A (LED+) | Backlight anode (connect to +5V through a resistor if needed) |
| 16 | K (LED-) | Backlight cathode (connect to ground) |
The LCD 20x4 can be connected to an Arduino UNO using the 4-bit mode to save pins. Below is a typical wiring configuration:
| LCD Pin | Arduino Pin | Description |
|---|---|---|
| VSS | GND | Ground |
| VDD | 5V | Power supply |
| VO | Potentiometer | Contrast adjustment |
| RS | Pin 12 | Register Select |
| RW | GND | Write mode (always 0) |
| E | Pin 11 | Enable signal |
| D4 | Pin 5 | Data bit 4 |
| D5 | Pin 4 | Data bit 5 |
| D6 | Pin 3 | Data bit 6 |
| D7 | Pin 2 | Data bit 7 |
| A (LED+) | 5V | Backlight anode |
| K (LED-) | GND | Backlight cathode |
Below is an example code to display text on the LCD 20x4 using the Arduino LiquidCrystal library:
#include <LiquidCrystal.h>
// Initialize the library with the pins connected to the LCD
// (RS, E, D4, D5, D6, D7)
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
void setup() {
// Set up the LCD's number of columns and rows
lcd.begin(20, 4);
// Print a message to the LCD
lcd.setCursor(0, 0); // Set cursor to column 0, row 0
lcd.print("Hello, World!");
lcd.setCursor(0, 1); // Set cursor to column 0, row 1
lcd.print("LCD 20x4 Demo");
lcd.setCursor(0, 2); // Set cursor to column 0, row 2
lcd.print("Line 3 Example");
lcd.setCursor(0, 3); // Set cursor to column 0, row 3
lcd.print("Line 4 Example");
}
void loop() {
// Nothing to do here
}
lcd.clear() function in the Arduino LiquidCrystal library to clear the screen.lcd.createChar() function to define and display them.This concludes the documentation for the LCD 20x4 module.