arduino : html5 : css3


LCD1602 2 line by 16 character backlit display.


LCD1602 2 line by 16 character backlit display as supplied.


Detail showing pads numbered 1 to 16.


LCD1602 back of display module.


1602 on breadboard connected to UNO and happily running the test program.

The connections that worked were as follows (1602 connections first):-

pad 1 = VSS and connects to GND on UNO.

pad 2 = VDD and connects to 5V on UNO.

pad 3 = V0 (display contrast) and connects to GND on UNO. ** see note below

pad 4 = RS and connects to D12 on UNO.

pad 5 = R/W and connects to GND on UNO.

pad 6 = Enable and connects to D11 on UNO.

pads 7, 8, 9 and 10 are not connected.

pad 11 = D4 and connects to D5 on UNO.

pad 12 = D5 and connects to D4 on UNO.

pad 13 = D6 and connects to D3 on UNO.

pad 14 = D7 and connects to D2 on UNO.

pad 15 = A (anode) and connects via a 270ohm resistor to 5V on UNO.pad 16 = K (cathode) and connects to GND on UNO.

** The connections on the arduino.cc page show this connected to the wiper of a 10K pot (pot connected to 5V and GND). However I found that the display contrast was right with the pot turned to zero, so to simplify things I've removed it and simply connected pad 3 to GND. If the contrast is too strong you may need to add the pot.

Test sketch / program is below, you should be able to cut and paste this into the Arduino IDE.

The only LCD library required is "LiquidCrystal" which comes pre-installed with the Arduino IDE (at least on version 1.0.1 and 1.0.5 that I've checked). So hopefully compiling the program will not be a problem.

Test Sketch (program) from arduino.cc site:-

LiquidCrystal Library - Hello World
Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
library works with all LCD displays that are compatible with the 
Hitachi HD44780 driver. There are many of them out there, and you
can usually tell them by the 16-pin interface.
This sketch prints "Hello World!" to the LCD
and shows the time.
 The circuit:
* LCD RS pin to digital pin 12
* LCD Enable pin to digital pin 11
* LCD D4 pin to digital pin 5
* LCD D5 pin to digital pin 4
* LCD D6 pin to digital pin 3
* LCD D7 pin to digital pin 2
* LCD R/W pin to ground
* 10K resistor:
* ends to +5V and ground
* wiper to LCD VO pin (pin 3)
Library originally added 18 Apr 2008
by David A. Mellis
library modified 5 Jul 2009
by Limor Fried (http://www.ladyada.net)
example added 9 Jul 2009
by Tom Igoe
modified 22 Nov 2010
by Tom Igoe
This example code is in the public domain.


// include the library code:
#include <LiquidCrystal.h>
#include <Wire.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
// set up the LCD's number of columns and rows: 
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("hello, world!");

void loop() {
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
// print the number of seconds since reset: