arduino lcd display pins quotation

In this article discuss about the interfacing of a 16x2 Liquid Crystal Display with Arduino Uno. And then read the analog value using the inbuilt ADC of Arduino Uno. Here I am going to connect the LCD in parallel way. We can also interface this LCD with only just 4 wires. (I2C communication is used there). Stay tuned for that article. This article help you to interface LCD with Arduino and make your project to fight against Covid -19This article is mainly for beginners.The code explained line by line.

Why it is called 16x2 ? Because you can write 16 characters or numbers in column wise and 2 in row wise. This display have total of 16 pins. Here I only use 12 pins. Here we use the pins except D0, D1, D2, D3. Because here I interface the LCD in 4 bit mode.

Open Arduino IDE. Here we use "Liquid Crystal" library. This is an inbuilt library, so no need to install that library separately. First I am going to call this library.#include

Next initialize the library with the number of the interface pins. With the function "LiquidCrystal lcd()". The function has six attributes. These are the interface pins in the order of "RS, E, D4, D5, D6, D7". Here we use pins 12, 11, 5, 4, 3, 2. corresponding to above.LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

Now can call this display by "lcd". Next program the setup part. We need to set the number of columns and number of rows. Here I am using the LCD with 16 column and 2 rows. Set the number of columns and rows by the function "lcd.begin(16, 2)". If you have a display with 16 columns and 4 rows this become "lcd.begin(16, 4)". And set the A0 pin as input.lcd.begin(16,2);

We need a starting point to start printing. So set the cursor to that particular point by the function "lcd.setCursor()". This function have only two attribute. It is that starting points.(The number of column and number of row). Here I am staring from first column first row. The first column is represented as 0, second is 1, and so on and the first raw is represented as 0, second is 1. So we need to start from the position (0, 0). You can easily understand if you know about matrix. The piece of code become,lcd.setCursor(0,0);

Next is the core part of this article. The instruction to print. I am going to print "Hello Hackster" by the instruction "lcd.print()". Alternatively you can print any thing. Please don, t forgot the double quote marks.lcd.print("Hello Hackster");

In the above printing statement we use total of 14 characters. So the current position of cursor is at (14, 0). Next I am going to print on the next line, ie the position (0, 1). Set the cursor to that point by the function "lcd.setCursor()".lcd.setCursor(0,1);

Now the cursor is at the position of second row and first column(0, 1). Then print another text "Value" by the function lcd.print().lcd.print("Value : ");

Here we use 8 characters in second line. So the current position of cursor is (8, 1). Next we need to read the analog value from the pin A0. For more about analog value conversion please see my previous article here. And print it to the display. I use the function "analogRead()" function to read the analog value and use the "lcd.print()" function to print the value to the display. And there is no need of double qunotes.lcd.print(analogRead(A0));

Next I add some delay. Otherwise the text will blinks continusoly. That because of the first instruction "lcd.clear()". Every time when see this command the Arduino will clear the display, This results the blinking of display. But use of delay will decrease this blinking.delay(500);

Connect the LCD to the Arduino Uno. You can use a breadboard or just use the jumber wires. For permanent connection use a LCD shield for Arduino Uno.The connection diagram is given in the Schematics part. Please careful about the backlight LED connection. Over voltage will kill that LED.Please don"t copy-paste my code. Try to understand the code line by line and create your own sketch.

In this tutorial, I’ll explain how to set up an LCD on an Arduino and show you all the different ways you can program it. I’ll show you how to print text, scroll text, make custom characters, blink text, and position text. They’re great for any project that outputs data, and they can make your project a lot more interesting and interactive.

The display I’m using is a 16×2 LCD display that I bought for about $5. You may be wondering why it’s called a 16×2 LCD. The part 16×2 means that the LCD has 2 lines, and can display 16 characters per line. Therefore, a 16×2 LCD screen can display up to 32 characters at once. It is possible to display more than 32 characters with scrolling though.

The code in this article is written for LCD’s that use the standard Hitachi HD44780 driver. If your LCD has 16 pins, then it probably has the Hitachi HD44780 driver. These displays can be wired in either 4 bit mode or 8 bit mode. Wiring the LCD in 4 bit mode is usually preferred since it uses four less wires than 8 bit mode. In practice, there isn’t a noticeable difference in performance between the two modes. In this tutorial, I’ll connect the LCD in 4 bit mode.

Here’s a diagram of the pins on the LCD I’m using. The connections from each pin to the Arduino will be the same, but your pins might be arranged differently on the LCD. Be sure to check the datasheet or look for labels on your particular LCD:

Also, you might need to solder a 16 pin header to your LCD before connecting it to a breadboard. Follow the diagram below to wire the LCD to your Arduino:

All of the code below uses the LiquidCrystal library that comes pre-installed with the Arduino IDE. A library is a set of functions that can be easily added to a program in an abbreviated format.

In order to use a library, it needs be included in the program. Line 1 in the code below does this with the command #include . When you include a library in a program, all of the code in the library gets uploaded to the Arduino along with the code for your program.

Now we’re ready to get into the programming! I’ll go over more interesting things you can do in a moment, but for now lets just run a simple test program. This program will print “hello, world!” to the screen. Enter this code into the Arduino IDE and upload it to the board:

There are 19 different functions in the LiquidCrystal library available for us to use. These functions do things like change the position of the text, move text across the screen, or make the display turn on or off. What follows is a short description of each function, and how to use it in a program.

TheLiquidCrystal() function sets the pins the Arduino uses to connect to the LCD. You can use any of the Arduino’s digital pins to control the LCD. Just put the Arduino pin numbers inside the parentheses in this order:

This function sets the dimensions of the LCD. It needs to be placed before any other LiquidCrystal function in the void setup() section of the program. The number of rows and columns are specified as lcd.begin(columns, rows). For a 16×2 LCD, you would use lcd.begin(16, 2), and for a 20×4 LCD you would use lcd.begin(20, 4).

This function clears any text or data already displayed on the LCD. If you use lcd.clear() with lcd.print() and the delay() function in the void loop() section, you can make a simple blinking text program:

Similar, but more useful than lcd.home() is lcd.setCursor(). This function places the cursor (and any printed text) at any position on the screen. It can be used in the void setup() or void loop() section of your program.

The cursor position is defined with lcd.setCursor(column, row). The column and row coordinates start from zero (0-15 and 0-1 respectively). For example, using lcd.setCursor(2, 1) in the void setup() section of the “hello, world!” program above prints “hello, world!” to the lower line and shifts it to the right two spaces:

You can use this function to write different types of data to the LCD, for example the reading from a temperature sensor, or the coordinates from a GPS module. You can also use it to print custom characters that you create yourself (more on this below). Use lcd.write() in the void setup() or void loop() section of your program.

The function lcd.noCursor() turns the cursor off. lcd.cursor() and lcd.noCursor() can be used together in the void loop() section to make a blinking cursor similar to what you see in many text input fields:

Cursors can be placed anywhere on the screen with the lcd.setCursor() function. This code places a blinking cursor directly below the exclamation point in “hello, world!”:

This function creates a block style cursor that blinks on and off at approximately 500 milliseconds per cycle. Use it in the void loop() section. The function lcd.noBlink() disables the blinking block cursor.

This function turns on any text or cursors that have been printed to the LCD screen. The function lcd.noDisplay() turns off any text or cursors printed to the LCD, without clearing it from the LCD’s memory.

This function takes anything printed to the LCD and moves it to the left. It should be used in the void loop() section with a delay command following it. The function will move the text 40 spaces to the left before it loops back to the first character. This code moves the “hello, world!” text to the left, at a rate of one second per character:

Like the lcd.scrollDisplay() functions, the text can be up to 40 characters in length before repeating. At first glance, this function seems less useful than the lcd.scrollDisplay() functions, but it can be very useful for creating animations with custom characters.

lcd.noAutoscroll() turns the lcd.autoscroll() function off. Use this function before or after lcd.autoscroll() in the void loop() section to create sequences of scrolling text or animations.

This function sets the direction that text is printed to the screen. The default mode is from left to right using the command lcd.leftToRight(), but you may find some cases where it’s useful to output text in the reverse direction:

This code prints the “hello, world!” text as “!dlrow ,olleh”. Unless you specify the placement of the cursor with lcd.setCursor(), the text will print from the (0, 1) position and only the first character of the string will be visible.

This command allows you to create your own custom characters. Each character of a 16×2 LCD has a 5 pixel width and an 8 pixel height. Up to 8 different custom characters can be defined in a single program. To design your own characters, you’ll need to make a binary matrix of your custom character from an LCD character generator or map it yourself. This code creates a degree symbol (°):

This tutorial includes everything you need to know about controlling a character LCD with Arduino. I have included a wiring diagram and many example codes. These displays are great for displaying sensor data or text and they are also fairly cheap.

The first part of this article covers the basics of displaying text and numbers. In the second half, I will go into more detail on how to display custom characters and how you can use the other functions of the LiquidCrystal Arduino library.

As you will see, you need quite a lot of connections to control these displays. I therefore like to use them with an I2C interface module mounted on the back. With this I2C module, you only need two connections to control the LCD. Check out the tutorial below if you want to use an I2C module as well:

These LCDs are available in many different sizes (16×2 1602, 20×4 2004, 16×1 etc.), but they all use the same HD44780 parallel interface LCD controller chip from Hitachi. This means you can easily swap them. You will only need to change the size specifications in your Arduino code.

For more information, you can check out the datasheets below. The 16×2 and 20×4 datasheets include the dimensions of the LCD and in the HD44780 datasheet you can find more information about the Hitachi LCD driver.

Most LCDs have a built-in series resistor for the LED backlight. You should find it on the back of the LCD connected to pin 15 (Anode). If your display doesn’t include a resistor, you will need to add one between 5 V and pin 15. It should be safe to use a 220Ω resistor, but this value might make your display a bit dim. You can check the datasheet for the maximum current rating of the backlight and use this to select an appropriate resistor value.

After you have wired up the LCD, you will need to adjust the contrast of the display. This is done by turning the 10 kΩ potentiometer clockwise or counterclockwise.

Plug in the USB connector of the Arduino to power the LCD. You should see the backlight light up. Now rotate the potentiometer until one (16×2 LCD) or 2 rows (20×4 LCD) of rectangles appear.

In order to control the LCD and display characters, you will need to add a few extra connections. Check the wiring diagram below and the pinout table from the introduction of this article.

We will be using the LCD in 4-bit mode, this means you don’t need to connect anything to D0-D3. The R/W pin is connected to ground, this will pull the pin LOW and set the LCD to WRITE mode.

To control the LCD we will be using the LiquidCrystal library. This library should come pre-installed with the Arduino IDE. You can find it by going to Sketch > Include Library > LiquidCrystal.

The example code below shows you how to display a message on the LCD. Next, I will show you how the code works and how you can use the other functions of the LiquidCrystal library.

After including the library, the next step is to create a new instance of the LiquidCrystal class. The is done with the function LiquidCrystal(rs, enable, d4, d5, d6, d7). As parameters we use the Arduino pins to which we connected the display. Note that we have called the display ‘lcd’. You can give it a different name if you want like ‘menu_display’. You will need to change ‘lcd’ to the new name in the rest of the sketch.

In the loop() the cursor is set to the third column and first row of the LCD with lcd.setCursor(2,0). Note that counting starts at 0, and the first argument specifies the column. If you do not specify the cursor position, the text will be printed at the default home position (0,0) if the display is empty, or behind the last printed character.

Next, the string ‘Hello World!’ is printed with lcd.print("Hello World!"). Note that you need to place quotation marks (” “) around the text. When you want to print numbers or variables, no quotation marks are necessary.

The LiquidCrystal Arduino library has many other built-in functions which you might find useful. You can find an overview of them below with explanation and some code snippets.

Clears the LCD screen and positions the cursor in the upper-left corner (first row and first column) of the display. You can use this function to display different words in a loop.

This function turns off any text or cursors printed to the LCD. The text/data is not cleared from the LCD memory. This means it will be shown again when the function display() is called.

Scrolls the contents of the display (text and cursor) one space to the left. You can use this function in the loop section of the code in combination with delay(500), to create a scrolling text animation.

This function turns on automatic scrolling of the LCD. This causes each character output to the display to push previous characters over by one space. If the current text direction is left-to-right (the default), the display scrolls to the left; if the current direction is right-to-left, the display scrolls to the right. This has the effect of outputting each new character to the same location on the LCD.

The following example sketch enables automatic scrolling and prints the character 0 to 9 at the position (16,0) of the LCD. Change this to (20,0) for a 20×4 LCD.

With the function createChar() it is possible to create and display custom characters on the LCD. This is especially useful if you want to display a character that is not part of the standard ASCII character set.

Technical info: LCDs that are based on the Hitachi HD44780 LCD controller have two types of memories: CGROM and CGRAM (Character Generator ROM and RAM). CGROM generates all the 5 x 8 dot character patterns from the standard 8-bit character codes. CGRAM can generate user-defined character patterns.

/* Example sketch to create and display custom characters on character LCD with Arduino and LiquidCrystal library. For more info see www.www.makerguides.com */

After including the library and creating the LCD object, the custom character arrays are defined. Each array consists of 8 bytes, 1 byte for each row. In this example 8 custom characters are created.

In this article I have shown you how to use an alphanumeric LCD with Arduino. I hope you found it useful and informative. If you did, please share it with a friend that also likes electronics and making things!

I would love to know what projects you plan on building (or have already built) with these LCDs. If you have any questions, suggestions, or if you think that things are missing in this tutorial, please leave a comment down below.

What is the purpose of declaring LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); if we are using pins A4 and A5? I know that 0x27 is the ic address but what is the rest for?

I am getting a error while i m going to add zip file of lcd library error id this zip file does not contains a valid library please help me to resolve this issue as soon as possible.....

Hey guys. My LCD works fine using the above instructions (when replacing the existing LCD library in the Arduino directory) but I can"t get the backlight to ever switch off. Suggestions?

I have got an 16 x 2 LCD display working OK on my Uno board, using the Pin assignments; D2, D3, D4, D5, D11, D12, as per the tutorial http://www.arduino.cc/en/Tutorial/LiquidCrystal and am now building my project as a standalone using a 328P-PU and some stripboard ect.

It would be a much neater layout if I could wire the LCD via one side of the chip"s pins, such as D0, D1, D2, D3, D4, D5 instead of the tutorial"s pins (the tutorial actually quotes pins D0 - D7 in the text, but then goes onto use different pins??)

In this Arduino tutorial we will learn how to connect and use an LCD (Liquid Crystal Display)with Arduino. LCD displays like these are very popular and broadly used in many electronics projects because they are great for displaying simple information, like sensors data, while being very affordable.

You can watch the following video or read the written tutorial below. It includes everything you need to know about using an LCD character display with Arduino, such as, LCD pinout, wiring diagram and several example codes.

An LCD character display is a unique type of display that can only output individual ASCII characters with fixed size. Using these individual characters then we can form a text.

If we take a closer look at the display we can notice that there are small rectangular areas composed of 5×8 pixels grid. Each pixel can light up individually, and so we can generate characters within each grid.

The number of the rectangular areas define the size of the LCD. The most popular LCD is the 16×2 LCD, which has two rows with 16 rectangular areas or characters. Of course, there are other sizes like 16×1, 16×4, 20×4 and so on, but they all work on the same principle. Also, these LCDs can have different background and text color.

It has 16 pins and the first one from left to right is the Groundpin. The second pin is the VCCwhich we connect the 5 volts pin on the Arduino Board. Next is the Vo pin on which we can attach a potentiometer for controlling the contrast of the display.

Next, The RSpin or register select pin is used for selecting whether we will send commands or data to the LCD. For example if the RS pin is set on low state or zero volts, then we are sending commands to the LCD like: set the cursor to a specific location, clear the display, turn off the display and so on. And when RS pin is set on High state or 5 volts we are sending data or characters to the LCD.

Next comes the R/W pin which selects the mode whether we will read or write to the LCD. Here the write mode is obvious and it is used for writing or sending commands and data to the LCD. The read mode is used by the LCD itself when executing the program which we don’t have a need to discuss about it in this tutorial.

Next is the E pin which enables the writing to the registers, or the next 8 data pins from D0 to D7. So through this pins we are sending the 8 bits data when we are writing to the registers or for example if we want to see the latter uppercase A on the display we will send 0100 0001 to the registers according to the ASCII table. The last two pins A and K, or anode and cathode are for the LED back light.

After all we don’t have to worry much about how the LCD works, as the Liquid Crystal Library takes care for almost everything. From the Arduino’s official website you can find and see the functions of the library which enable easy use of the LCD. We can use the Library in 4 or 8 bit mode. In this tutorial we will use it in 4 bit mode, or we will just use 4 of the 8 data pins.

We will use just 6 digital input pins from the Arduino Board. The LCD’s registers from D4 to D7 will be connected to Arduino’s digital pins from 4 to 7. The Enable pin will be connected to pin number 2 and the RS pin will be connected to pin number 1. The R/W pin will be connected to Ground and theVo pin will be connected to the potentiometer middle pin.

We can adjust the contrast of the LCD by adjusting the voltage input at the Vo pin. We are using a potentiometer because in that way we can easily fine tune the contrast, by adjusting input voltage from 0 to 5V.

Yes, in case we don’t have a potentiometer, we can still adjust the LCD contrast by using a voltage divider made out of two resistors. Using the voltage divider we need to set the voltage value between 0 and 5V in order to get a good contrast on the display. I found that voltage of around 1V worked worked great for my LCD. I used 1K and 220 ohm resistor to get a good contrast.

There’s also another way of adjusting the LCD contrast, and that’s by supplying a PWM signal from the Arduino to the Vo pin of the LCD. We can connect the Vo pin to any Arduino PWM capable pin, and in the setup section, we can use the following line of code:

It will generate PWM signal at pin D11, with value of 100 out of 255, which translated into voltage from 0 to 5V, it will be around 2V input at the Vo LCD pin.

First thing we need to do is it insert the Liquid Crystal Library. We can do that like this: Sketch > Include Library > Liquid Crystal. Then we have to create an LC object. The parameters of this object should be the numbers of the Digital Input pins of the Arduino Board respectively to the LCD’s pins as follow: (RS, Enable, D4, D5, D6, D7). In the setup we have to initialize the interface to the LCD and specify the dimensions of the display using the begin()function.

The cursor() function is used for displaying underscore cursor and the noCursor() function for turning off. Using the clear() function we can clear the LCD screen.

In case we have a text with length greater than 16 characters, we can scroll the text using the scrollDisplayLeft() orscrollDisplayRight() function from the LiquidCrystal library.

We can choose whether the text will scroll left or right, using the scrollDisplayLeft() orscrollDisplayRight() functions. With the delay() function we can set the scrolling speed.

So, we have covered pretty much everything we need to know about using an LCD with Arduino. These LCD Character displays are really handy for displaying information for many electronics project. In the examples above I used 16×2 LCD, but the same working principle applies for any other size of these character displays.

I hope you enjoyed this tutorial and learned something new. Feel free to ask any question in the comments section below and don’t forget to check out my full collection of 30+ Arduino Projects.

Arduino LCD Display Modules are mostly used in embedded projects, because of its affordability and availability. The 16×2 Display LCD Module represents 16 Columns and 2 Rows. There are so many other combinations like 8×1, 8×2, 10×2, 16×1 and so on. However, 16 x 2 display LCD is most commonly used.

Arduino 16×2 LCD Display Module has 16 characters by a 2-line LCD display screen with an I2C interface. It displays 2 lines of 16 characters, white characters are displayed on a blue background.

This I2C 16×2 Arduino LCD Display Module uses the I2C communication interface. This means that we can use 4 pins for the display that is: VCC, GND, SDA, SCL. Thus, it gives us the advantage of saving 4 digital / analog pins on Arduino.

Most of the time we use the serial plotter of the Arduino IDE to visualize our solutions or output of a sketch. This is great and a big time saver when you are doing prototyping. But there is a time when your system will go live. If you are for example only sending data from sensors to a database on a Raspberry Pi, than you are able to view the output remote from your PC by connecting to the database. But there are use cases like an indoor weather station, where you want to see the output like the current temperature directly and not when you are on you PC.

Than displays are the way to go. There are different kinds of displays like 7 Segment LED display, 4 Digit 7 Segment display, 8×8 Dot Matrix display, OLED display or the easiest and cheapest version the liquid crystal display (LCD).

Most LCD displays have either 2 rows with 16 characters per row or 4 rows with 20 characters per row. There are LCD screen with and without I2C module. I highly suggest the modules with I2C because the connection to the board is very easy and there are only 2 instead of 6 pins used. But we will cover the LCD screen with and without I2C module in this article.

The LCD display has an operating voltage between 4.7V and 5.3V with a current consumption of 1mA without backlight and 120mA with full backlight. There are version with a green and also with a blue backlight color. Each character of the display is build by a 5×8 pixel box and is therefore able to display custom generated characters. Because each character is build by (5×8=40) 40 pixels a 16×2 LCD display will have 16x2x40= 1280 pixels in total. The LCD module is able to operate in 8-bit and 4-bit mode. The difference between the 4-bit and 8-bit mode are the following:

If we use the LCD display version without I2C connection we have to add the potentiometer manually to control the contrast of the screen. The following picture shows the pinout of the LCD screen.

Also I added a table how to connect the LCD display with the Arduino Uno and the NodeMCU with a description of the LCD pin. To make it as easy as possible for you to connect your microcontroller to the display, you find the corresponding fritzing connection picture for the Arduino Uno and the NodeMCU in this chapter.

3VEEPotentiometerPotentiometerAdjusts the contrast of the display If this pin is grounded, you get the maximum contrast. We will connect the VEE pin to the potentiometer output to adjust the contrast by changing the resistance of the potentiometer.

4RSD12D2Select command register to low when we are sending commands to the LCD like set the cursor to a specific location, clear the display or turn off the display.

7Data Pin 0 (d0)Connected to microcontroller pin and toggled between 1 and 0 for data acknowledgement. So if we want to send data via the data pins 0 to 7, we have to make sure that the enable pin is high.

8Data Pin 1 (d1)Data pins 0 to 7 forms an 8-bit data line. The Data Pins are connection to the Digital I/O pins of the microcontroller to send 8-bit data. These LCD’s can also operate on 4-bit mode in such case Data pin 4,5,6 and 7 will be left free.

Of cause we want to try the connection between the microcontroller and the LCD display. Therefore you find an example sketch in the Arduino IDE. The following section shows the code for the sketch and a picture of the running example, more or less because it is hard to make a picture of the screen ;-). The example prints “hello, world!” in the first line of the display and counts every second in the second row. We use the connection we described before for this example.

Looks very complicated to print data onto the LCD screen. But don’t worry like in most cases if it starts to get complicated, there is a library to make the word for us. This is also the case for the LCD display without I2C connection.

Therefore the next step is to install the library “LiquidCrystal”. You find here an article how to install an external library via the Arduino IDE. After you installed the library successful you can include the library via: #include < LiquidCrystal.h>.

Like I told you, I would suggest the LCD modules with I2C because you only need 2 instead of 6 pins for the connection between display and microcontroller board. In the case you use the I2C communication between LCD and microcontroller, you need to know the I2C HEX address of the LCD. In this article I give you a step by step instruction how to find out the I2C HEX address of a device. There is also an article about the I2C communication protocol in detail.

The following picture shows how to connect an I2C LCD display with an Arduino Uno. We will use exact this connection for all of the examples in this article.

To use the I2C LCD display we have to install the required library “LiquidCrystal_I2C” by Frank de Brabander. You find here an article how to install an external library via the Arduino IDE. After you installed the library successful you can include the library via: #include < LiquidCrystal_I2C.h>.

The LiquidCrystal library has 20 build in functions which are very handy when you want to work with the LCD display. In the following part of this article we go over all functions with a description as well as an example sketch and a short video that you can see what the function is doing.

LiquidCrystal_I2C()This function creates a variable of the type LiquidCrystal. The parameters of the function define the connection between the LCD display and the Arduino. You can use any of the Arduino digital pins to control the display. The order of the parameters is the following: LiquidCrystal(RS, R/W, Enable, d0, d1, d2, d3, d4, d5, d6, d7)

If you are using an LCD display with the I2C connection you do not define the connected pins because you do not connected to single pins but you define the HEX address and the display size: LiquidCrystal_I2C lcd(0x27, 20, 4);

xlcd.begin()The lcd.begin(cols, rows) function has to be called to define the kind of LCD display with the number of columns and rows. The function has to be called in the void setup() part of your sketch. For the 16x2 display you write lcd.begin(16,2) and for the 20x4 lcd.begin(20,4).

xxlcd.clear()The clear function clears any data on the LCD screen and positions the cursor in the upper-left corner. You can place this function in the setup function of your sketch to make sure that nothing is displayed on the display when you start your program.

xxlcd.setCursor()If you want to write text to your LCD display, you have to define the starting position of the character you want to print onto the LCD with function lcd.setCursor(col, row). Although you have to define the row the character should be displayed.

xxlcd.print()This function displays different data types: char, byte, int, long, or string. A string has to be in between quotation marks („“). Numbers can be printed without the quotation marks. Numbers can also be printed in different number systems lcd.print(data, BASE) with BIN for binary (base 2), DEC for decimal (base 10), OCT for octal (base 8), HEX for hexadecimal (base 16).

xlcd.println()This function displays also different data types: char, byte, int, long, or string like the function lcd.print() but lcd.println() prints always a newline to output stream.

xxlcd.display() / lcd.noDisplay()This function turn on and off any text or cursor on the display but does not delete the information from the memory. Therefore it is possible to turn the display on and off with this function.

xxlcd.scrollDisplayLeft() / lcd.scrollDisplayRight()This function scrolls the contents of the display (text and cursor) a one position to the left or to the right. After 40 spaces the function will loops back to the first character. With this function in the loop part of your sketch you can build a scrolling text function.

Scrolling text if you want to print more than 16 or 20 characters in one line, than the scrolling text function is very handy. First the substring with the maximum of characters per line is printed, moving the start column from the right to the left on the LCD screen. Than the first character is dropped and the next character is printed to the substring. This process repeats until the full string is displayed onto the screen.

xxlcd.autoscroll() / lcd.noAutoscroll()The autoscroll function turn on or off the functionality that each character is shifted by one position. The function can be used like the scrollDisplayLeft / scrollDisplayRight function.

xxlcd. leftToRight() / lcd.rightToLeft()The leftToRight and rightToLeft functions changes the direction for text written to the LCD. The default mode is from left to right which you do not have to define at the start of the sketch.

xxlcd.createChar()There is the possibility to create custom characters with the createChar function. How to create the custom characters is described in the following chapter of this article as well as an example.

xlcd.backlight()The backlight function is useful if you do not want to turn off the whole display (see lcd.display()) and therefore only switch on and off the backlight. But before you can use this function you have to define the backlight pin with the function setBacklightPin(pin, polarity).

xlcd.moveCursorLeft() / lcd.moveCursorRight()This function let you move the curser to the left and to the right. To use this function useful you have to combine it with lcd.setCursor() because otherwise there is not cursor to move left or right. For our example we also use the function lcd.cursor() to make the cursor visible.

xlcd.on() / lcd.off()This function switches the LCD display on and off. It will switch on/off the LCD controller and the backlight. This method has the same effect of calling display/noDisplay and backlight/noBacklight.

Show or hide a cursor (“_”) that is useful when you create a menu as navigation bar from the left to the right or from the top to the bottom, depending on a horizontal of vertical menu bar. If you are interested how to create a basic menu with the ESP or Arduino microcontroller in combination with the display, you find here a tutorial.

The following code shows you the Arduino program to use all three LCD display functions of the library divided into three separate functions. Also the video after the program shows the functions in action.

The creation of custom characters is very easy if you use the previous mentioned libraries. The LiquidCrystal and also the LiquidCrystal_I2C library have the function “lcd.createChar()” to create a custom character out of the 5×8 pixels of one character. To design your own characters, you need to make a binary matrix of your custom character from an LCD character generator or map it yourself. This code creates a wiggling man.

In the section of the LCD display pinout without I2C we saw that if we set the RS pin to how, that we are able to send commands to the LCD. These commands are send by the data pins and represented by the following table as HEX code.

While in theory an Arduino can run any LCD, we believe that some LCDs are particularly suited to being an Arduino LCD display. We"ve currated this list of LCD displays that will make any Arduino-based project shine.

First is the interface. All of these displays support SPI. Builders often ask themselves (or us) "which interface uses the fewest GPIO pins? AND is that interface fast enough to update the screen at an acceptable rate for my application?" When using the relatively small procesor of the Arduino, SPI is usually the best interface because it takes few wires (either 3 or 4) however it does limit the overall size (number of pixels) that can be quickly controlled. I2C is another choice of interface to leave GPIOs open. We tend to recommend SPI over I2C for Arduino displays because SPI is quicker and better at handling more complex data transfer, like pulling image data from an SD card.

Which brings us to the second factor in choosing an Arduino display: the number of pixels. We typically recommend a display with a resolution of 320x240 or less for use with Arduino. Take for example a 320x240 24-bit display. Such a display takes 230,400 bytes *(8 + 2) = 2,304,000 bits for a single frame. Divide that by 8,000,000 (Arduino SPI speed of 8MHZ) = 0.288 seconds per frame or 3.5 frames per second. 3.5 fps is fast enough for many applications, but is not particularly quick. Using fewer bits-per-pixel or a display with fewer pixels will result in higher frame rates. Use the calculator below to calculate the frame rate for a display using SPI with an Arduino.

Third, we want to recommend displays that are easy to connect to an Arduino. Each of these displays has a ZIF tail or easily solderable throughholes, so no fine pitch soldering is needed. These displays can either be brought up on the CFA10102 generic breakout board, or with a custom CFA breakout board.

Most character displays can be run via Parallel connection to an Arduino. You"ll want to make sure you can supply enough current to operate the backlight.

Firstly, I would recommend a matrix keypad instead of the DTMF keypad as it is much easier to use with an Arduino. This will also allow you to use a multiplexer which would use fewer pins.