"Hello
World!"
The LiquidCrystal library allows you to control 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
example sketch prints "Hello World!" to the LCD and shows the time in
seconds since the Arduino was reset.
output of the sketch
on a 2x16 LCD
The LCDs have a parallel interface, meaning
that the microcontroller has to manipulate several interface pins at once to
control the display. The interface consists of the following pins:
A register select (RS) pin that controls where in the LCD's memory
you're writing data to. You can select either the data register, which holds
what goes on the screen, or an instruction register, which is where the LCD's
controller looks for instructions on what to do next.
A Read/Write (R/W) pin that
selects reading mode or writing mode
An Enable pin that
enables writing to the registers
8 data pins (D0 -D7). The states of these pins
(high or low) are the bits that you're writing to a register when you write, or
the values you're reading when you read.
There's
also a display constrast pin (Vo), power supply pins (+5V and Gnd) and LED Backlight (Bklt+ and BKlt-) pins
that you can use to power the LCD, control the display contrast, and turn on
and off the LED backlight, respectively.
The
process of controlling the display involves putting the data that form the
image of what you want to display into the data registers, then putting
instructions in the instruction register. The LiquidCrystal Library simplifies this for you so you don't need
to know the low-level instructions.
The
Hitachi-compatible LCDs can be
controlled in two modes: 4-bit or 8-bit. The 4-bit mode requires seven I/O pins
from the Arduino, while the 8-bit mode requires 11 pins. For displaying text on
the screen, you can do most everything in 4-bit mode, so example shows how to
control a 2x16 LCD in 4-bit mode.
Hardware Required
· Arduino or
Genuino Board
· LCD Screen
(compatible with Hitachi HD44780 driver)
· pin
headers to solder to the LCD display pins
· 10k ohm
potentiometer
· 220 ohm
resistor
· hook-up
wires
· breadboard
Circuit
Before wiring the LCD screen to your Arduino or Genuino board we
suggest to solder a pin header strip to the 14 (or 16) pin count connector of
the LCD screen, as you can see in the image above.
To wire your LCD screen to your board, connect the following pins:
· 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
Additionally, wire a 10k pot to +5V and GND, with it's wiper
(output) to LCD screens VO pin (pin3). A 220 ohm resistor is used to power the
backlight of the display, usually on pin 15 and 16 of the LCD connector
Schematic
Code
/*
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
* LCD VSS pin to ground
* LCD VCC pin to 5V
* 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.
http://www.arduino.cc/en/Tutorial/LiquidCrystal
*/
// include the library code:
#include <LiquidCrystal.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("ABIOLA
J.OPEYEMI");
}
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:
lcd.print(millis() /
1000);
}
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