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Arduino Due

Arduino Due and I2C LCD example

by shedboy71
written by shedboy71

In this example we will interface to an I2C LCD using our Arduino Due. Now these I2C LCD’s consist of 2 parts usually an HD44780 16×2 LCD and an I2C backpack which connects to the LCD exposing the standard power and I2C pins.

This is a typical module you can buy, you can see the backpack which is obviously on the back of the LCD when you buy it

We will now look at the connections and a simple layout

Layout

Connect the pins as follows, it works from 3.3v and also 5v so can be used with a wide range of boards

Arduino Due LCD1602
GND GND
3v3 VCC
SDA/21 SDA
SCL/22 SCL

 

Remember the backpack and lcd connections are already made for you

 

arduino due and i2c lcd

arduino due and i2c lcd

 

Code

You will need an updated I2C LCD library, the original one I couldn’t get to work but this one does seem to work.

LiquidCrystal_I2C-master

You will need to import this into the IDE as usual

Now my example below required the I2C address to be changed to 0x3F, a lot of the code examples I have looked at on the internet are set to 0x27, something to look out for there

 

[codesyntax lang=”cpp”]

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x3F,16,2); // set the LCD address to 0x3F for a 16 chars and 2 line display

void setup()
{
lcd.init(); // initialize the lcd
// Print a message to the LCD.
lcd.backlight();
lcd.setCursor(0,0);
lcd.print("Hello world");
lcd.setCursor(1,1);
lcd.print("Arduino Due");
}

void loop()
{

}

[/codesyntax]

 

All going well you should see the messages in the code on your LCD display, you may have to adjust the little pot on the board

Now that you have this stage complete its fairly simple to display time, temperature readings or anything else you want to display on the LCD display, we will look at this in later articles

 

Link

You can pick up one these modules for under $3

1pcs Blue Display IIC/I2C/TWI/SPI Serial Interface 1602 16X2 LCD Module

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Espruino

Espruino Pico time on LCD example

by shedboy71
written by shedboy71

This is similar to the previous example, this time we will display the time on our LCD. If you are familiar with JavaScript you will recognise some of the code

These displays were used in old Nokia 5110 cell phones. It is a 84×48 pixel monochrome LCD display and you can use it for graphics, text or bitmaps. To use the display, you will require 5 digital output pins. Another pin can be used to control the backlight.

lcd5110b

lcd5110a

The display driver is a PCD8544 chip (which is another name for the display), and you can safely run the display off 3.3v

Here is the connections I used

Connection

LCD pin Espruino Pico
GND GND
LIGHT N/C
VCC 3.3v
SCLK B3
DN(MOSI) B5
D/C B13
CE B14
RST B15

Schematic

here is a schematic

pico and nokia5110_bb

Code

[codesyntax lang=”javascript”]

var g;

function draw() 
{
  g.clear();
  var t = new Date();
  var time = t.getHours()+":" + ("0"+t.getMinutes()).substr(-2);
  var secs = ("0"+t.getSeconds()).substr(-2);
  g.setFontBitmap();
  g.setFontVector(20);
  var timeWidth = g.stringWidth(time);
  g.drawString(time,(g.getWidth()-timeWidth-12)/2,10);
  g.setFontBitmap();
  g.drawString(secs,(g.getWidth()+timeWidth-8)/2,26);
  g.flip();
}

function onInit() 
{
  clearInterval();
  // Setup SPI
  var SPI1 = new SPI();
  SPI1.setup({ sck:B3, mosi:B5 });
  // Initialise the LCD
  g = require("PCD8544").connect(SPI1, B13 /*DC*/, B14 /*CE*/, B15 /*RST*/, function(){
    setInterval(draw, 1000);
  });
}

onInit();

[/codesyntax]

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Code

Nucleo F334R8 LCD example

by shedboy71
written by shedboy71

In this example we will add an Arduino LCD keypad shield to a ST Nucleo F334R8. This is a 16×2 LCD Keypad module for Arduino Diecimila Duemilanove, UNO, MEGA1280, MEGA2.

It consists of a 1602 white character blue backlight LCD. The keypad consists of 5 keys — select, up, right, down and left. To save the digital IO pins, the keypad interface uses only one ADC channel. The key value is read through a 5 stage voltage divider.

Here are the pins and their functions

Pin Function
Analog 0 Button (select, up, right, down and left)
Digital 4 DB4
Digital 5 DB5
Digital 6 DB6
Digital 7 DB7
Digital 8 RS (Data or Signal Display Selection)
Digital 9 Enable
Digital 10 Backlit Control

Here is a picture of this shield

lcd keypad shield

lcd keypad shield

Code

The code is for the mBed online compiler at https://developer.mbed.org/ and uses the freetronics LCD library

[codesyntax lang=”cpp”]

#include "mbed.h"
#include "freetronicsLCDShield.h"
 
freetronicsLCDShield lcd(D8, D9, D4, D5, D6, D7, D1, A0);

 
int main() 
{
    lcd.cls();
    // print the first line and wait 3 sec
    lcd.printf("LCD test");
    wait(3);
    
    // print the counter prefix; the number will be printed in the while loop
    lcd.setCursorPosition(1, 0);
    lcd.printf("seconds : ");
    
    int i=1;
    while (i++) 
    {
        lcd.setCursorPosition(1, 11);
        lcd.printf("%d", i);
        wait(1);
    }
}

[/codesyntax]

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