how to test lcd display 16x2 quotation

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:

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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.

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.

When looking closely at the array, you will see the following. Each row consists of 5 numbers corresponding to the 5 pixels in a 5 x 8 dot character. A 0 means pixel off and a 1 means pixel on.

It is possible to edit each row by hand, but I recommend using this visual tool on GitHub. This application automatically creates the character array and you can click on the pixels to turn them on or off.

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.

Hi, I"m brand new to LCDs and Raspberry Pi GPIO. I"ve wired up a LMB162ABC 16x2 LCD that came in an Arduino Uno kit from Maker Faire. I"ve used just any open GPIO pins that I wanted figuring it doesn"t matter which ones I use as long as they are GPIO, is that correct? I want to operate in 4 bit mode so I have wired it accordingly. I get the screen to come on and the contrast variable resistor works and one row lights up solid blocks. I have tried a few python code examples and even adjusted the pins in the code to match the GPIO pins I chose and no matter what I do I cannot seem to get the dispaly to do anything (besides the solid row of blocks). Can someone please assist me with some super basic code or what I may be doing wrong? Here"s a link to a PDF of the specs for the LCD I"m using if it helps. http://www.datasheetdir.com/LMB162ABC+download

I tried Adafruit_CharLCD.py, nothing happened, wondering if the LCD it was written for was different and that"s why it"s not working...? I also posted this in the LCD screen section of the forum because I"m not really sure which area is a better fit for my issue.

I don"t see anything obviously wrong (my Python knowledge is very weak). These LCD devices are a pig to debug as you need everything correct to get any output.

Rezendes wrote:Hi, I"m brand new to LCDs and Raspberry Pi GPIO. I"ve wired up a LMB162ABC 16x2 LCD that came in an Arduino Uno kit from Maker Faire. I"ve used just any open GPIO pins that I wanted figuring it doesn"t matter which ones I use as long as they are GPIO, is that correct? I want to operate in 4 bit mode so I have wired it accordingly. I get the screen to come on and the contrast variable resistor works and one row lights up solid blocks. I have tried a few python code examples and even adjusted the pins in the code to match the GPIO pins I chose and no matter what I do I cannot seem to get the dispaly to do anything (besides the solid row of blocks). Can someone please assist me with some super basic code or what I may be doing wrong? Here"s a link to a PDF of the specs for the LCD I"m using if it helps. http://www.datasheetdir.com/LMB162ABC+download

I tried Adafruit_CharLCD.py, nothing happened, wondering if the LCD it was written for was different and that"s why it"s not working...? I also posted this in the LCD screen section of the forum because I"m not really sure which area is a better fit for my issue.

Do check the device voltage. Some 5v displays will not work at 3.3v - you can run them at 5v, but you must tie the r/w pin to 0v or you risk damaging your Pi...

If you have wiringPi, then there is some sample code there in C to drive these displays - see http://wiringpi.com/dev-lib/lcd-library/ for the details - and even if not programming in C it might be enough to double-check the wiring, display, etc.

Thanks for the replies, I have checked the physical connections a few times and they look fine. The display is 5v and I have made sure to Ground the R/W pin on the LCD. I did search and find that thread already and I have tried that code as well. I can"t imagine there are issues with all the code I have tried. I must have a physical problem... I will take some pictures of my wiring and use an ohmmeter to check each connection for sure.

I haven"t had time to take the pictures, I have checked the connections with the multimeter and everything seems fine and I think my contrast has always worked because it shows the solid row of black blocks. I will try the code you linked when I get a chance and post pictures if it"s allowed on these forums.

I am about to buy another LCD to test and make sure it"s not the LCD I have that"s the problem. The image here for the wiring of this LCD http://www.amazon.com/microtivity-IM161 ... icrotivity suggests a Diode on pins 15 and 2 pointing towards 15... Do I need that? That seems to be power to the LCD and power to the Backlight, my backlight powers up and my contrast adjustment works with the single row of solid blocks on screen... what exactly is pin 2 providing power for on the LCD?

The backlight appears to require about 4.2v and the diode is between it and the 5v supply. The diode will drop about 0.7v, so only 4.3v will get to the backlight which will be close enough to make it work without burning it out.

I already checked my connections with the multimeter though, I don"t have a diode in my setup and I"m wondering what it"s purpose is and If I Need one. Right now I"m sending 5v directly into pin 2 and 15.

1. it shows numbers and characters like #@$! in right way, but characters like "abcdefg" wrong, itshows !@#$ instead of alphabet, for example "*" for "j"

1. it shows numbers and characters like #@$! in right way, but characters like "abcdefg" wrong, itshows !@#$ instead of alphabet, for example "*" for "j"

1. it shows numbers and characters like #@$! in right way, but characters like "abcdefg" wrong, itshows !@#$ instead of alphabet, for example "*" for "j"

i use 4 bits connection and 0.0005 delay in time (same amount in sample code). i also have no pull up or pull downs, cause i don"t know which pins should be pull up or pull down (all data bits or only 4?) and with how much resistors, if you can help about this, i would be really thankful.

i use 4 bits connection and 0.0005 delay in time (same amount in sample code). i also have no pull up or pull downs, cause i don"t know which pins should be pull up or pull down (all data bits or only 4?) and with how much resistors, if you can help about this, i would be really thankful.

W.r.t. to the initialisation process, have you seen the HD44780U datasheet? (The relevant diagrams for 8-bit and 4-bit interfaces are figures 23 & 24**) Are you connecting the LCD directly to the Pi"s GPIO"s or, if it"s a 5V display, are you, like me, using level-shifters (see the links in my previous post)?

i use 4 bits connection and 0.0005 delay in time (same amount in sample code). i also have no pull up or pull downs, cause i don"t know which pins should be pull up or pull down (all data bits or only 4?) and with how much resistors, if you can help about this, i would be really thankful.

W.r.t. to the initialisation process, have you seen the HD44780U datasheet? (The relevant diagrams for 8-bit and 4-bit interfaces are figures 23 & 24**) Are you connecting the LCD directly to the Pi"s GPIO"s or, if it"s a 5V display, are you, like me, using level-shifters (see the links in my previous post)?

i use python and code is the same as this page. i don"t use level shifters for data bits (as said in link bellow), but i use . raspberry`s 5v out to power back light .i use procedure described here:

i use 4 bit, i think i have connected pins D4 to D7 right though there is no pull up or pull down resistors for D0 to D7 i don`t how should i do that. i personally have doubts about LCD`s solder too, although it shows no short circuit.

I think my second or third bit is stocked low, am i right? So pqrs: 0111 becomes 0011:0123 but 0123 stays 0123 cause it"s third bit is already 0 and make it low wont change it it was the reason a 0110 becomes ! 0010.

You"re getting "1234..." instead of "pqrs...". Initally that looks like a bit is staying low - as you suspected - and 0x01110001 "p" is getting sent as 0x00110001 "1", but then you have to remember that each character is getting sent as two lots of four bits, so "p" is 0x0111 and 0x0001. Now that still looks ok, but what about "u"? "u" is 0x0111 + 0x0111, which if that line were stuck would come out as 0x0011 and 0x0011 or "3", but it comes out as "7" 0x0011 + 0x0111. Therefore that line can"t be stuck.

You"re getting "1234..." instead of "pqrs...". Initally that looks like a bit is staying low - as you suspected - and 0x01110001 "p" is getting sent as 0x00110001 "1", but then you have to remember that each character is getting sent as two lots of four bits, so "p" is 0x0111 and 0x0001. Now that still looks ok, but what about "u"? "u" is 0x0111 + 0x0111, which if that line were stuck would come out as 0x0011 and 0x0011 or "3", but it comes out as "7" 0x0011 + 0x0111. Therefore that line can"t be stuck.

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.

BONUS: I made a quick start guide for this tutorial that you can download and go back to later if you can’t set this up right now. It covers all of the steps, diagrams, and code you need to get started.

The 3-in-1 Smart Car and IOT Learning Kit from SunFounder has everything you need to learn how to master the Arduino. It includes all of the parts, wiring diagrams, code, and step-by-step instructions for 58 different robotics and internet of things projects that are super fun to build!

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:

The resistor in the diagram above sets the backlight brightness. A typical value is 220 Ohms, but other values will work too. Smaller resistors will make the backlight brighter.

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.

These two functions can be used together in the void loop() section to create a blinking text effect. This code will make the “hello, world!” text blink on and off:

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:

This function takes a string of text and scrolls it from right to left in increments of the character count of the string. For example, if you have a string of text that is 3 characters long, it will shift the text 3 spaces to the left with each step:

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 (°):

If you found this article useful, subscribe via email to get notified when we publish of new posts! And as always, if you are having trouble with anything, just leave a comment and I’ll try to help you out.

This stems from the fact that the LCD controller itself does not inherently support the function and in fact treats the ASCII codes for and as displayable characters instead of control codes.

The fact that the LiquidCrystal library inherits from Print class and thus permits the use of println() essentially makes things worse. Instead of barfing and spitting out an error message it just happily displays two unrelated characters on the screen and the uninitiated have no idea of the cause.

In my opinion the basic LiquidCrystal library should concentrate on implementing all of the capabilities of the LCD controller and no more. If people want a library that more closely emulates a CRT (or LCD) terminal that is fine, but I think it should be done in a different library.

I have one of those and when I apply 5v to it coming off from 3.3v all of the characters that are written there become white squares just like it happens with your LCD, the solution is to go with a small screwdriver to the backside of it and dial down the brightness until you can see the characters again, maybe try supply it with less voltage.

P.S. I know you said you tried turning the dial down but please check first that you"re not outputting squares to the LCD by loading a simple "hello world" style program and going from there. Don"t forget to turn everything off for a few seconds and then ON again, also, there"s always the possibility that it"s your MCU that isn"t doing things right, if you have a second MCU that you know for a fact to be OK, use it to test the LCD. Don"t forget to check your connections.

Do you want your Arduino projects to display status messages or sensor readings? Then these LCD displays can be a perfect fit. They are extremely common and fast way to add a readable interface to your project.

This tutorial will help you get up and running with not only 16×2 Character LCD, but any Character LCD (16×4, 16×1, 20×4 etc.) that is based on Hitachi’s LCD Controller Chip – HD44780.

When current is applied to these crystals, they become opaque, blocking the backlight that resides behind the screen. As a result that particular area will be dark compared to the others. And this is how the characters are displayed on the screen.

True to their name, these LCDs are ideal for displaying only text/characters. A 16×2 character LCD, for example, has an LED backlight and can display 32 ASCII characters in two rows of 16 characters each.

If you look closely you can see tiny rectangles for each character on the display and the pixels that make up a character. Each of these rectangles is a grid of 5×8 pixels.

The good news is that all of these displays are ‘swappable’, which means if you build your project with one you can just unplug it and use another size/color LCD of your choice. Your code will have to change a bit but at least the wiring remains the same!

Vo (LCD Contrast) controls the contrast and brightness of the LCD. Using a simple voltage divider with a potentiometer, we can make fine adjustments to the contrast.

RS (Register Select) pin is set to LOW when sending commands to the LCD (such as setting the cursor to a specific location, clearing the display, etc.) and HIGH when sending data to the LCD. Basically this pin is used to separate the command from the data.

R/W (Read/Write) pin allows you to read data from the LCD or write data to the LCD. Since we are only using this LCD as an output device, we are going to set this pin LOW. This forces it into WRITE mode.

E (Enable) pin is used to enable the display. When this pin is set to LOW, the LCD does not care what is happening on the R/W, RS, and data bus lines. When this pin is set to HIGH, the LCD processes the incoming data.

D0-D7 (Data Bus) pins carry the 8 bit data we send to the display. For example, if we want to see an uppercase ‘A’ character on the display, we set these pins to 0100 0001 (as per the ASCII table).

Now we will power the LCD. The LCD has two separate power connections; One for the LCD (pin 1 and pin 2) and the other for the LCD backlight (pin 15 and pin 16). Connect pins 1 and 16 of the LCD to GND and 2 and 15 to 5V.

Most LCDs have a built-in series resistor for the LED backlight. You’ll find this near pin 15 on the back of the LCD. If your LCD does not include such a resistor or you are not sure if your LCD has one, you will need to add one between 5V and pin 15. It is safe to use a 220 ohm resistor, although a value this high may make the backlight a bit dim. For better results you can check the datasheet for maximum backlight current and select a suitable resistor value.

Next we will make the connection for pin 3 on the LCD which controls the contrast and brightness of the display. To adjust the contrast we will connect a 10K potentiometer between 5V and GND and connect the potentiometer’s center pin (wiper) to pin 3 on the LCD.

That’s it. Now turn on the Arduino. You will see the backlight lit up. Now as you turn the knob on the potentiometer, you will start to see the first row of rectangles. If that happens, Congratulations! Your LCD is working fine.

Let’s finish connecting the LCD to the Arduino. We have already made the connections to power the LCD, now all we have to do is make the necessary connections for communication.

We know that there are 8 data pins that carry data to the display. However, HD44780 based LCDs are designed in such a way that we can communicate with the LCD using only 4 data pins (4-bit mode) instead of 8 (8-bit mode). This saves us 4 pins!

8-bit mode is much faster than 4-bit mode because it takes half the time. In 8-bit mode you write the data in one go. Whereas in 4-bit mode you have to split a byte into 2 nibbles and perform two write operations.

4-bit mode is often used to save I/O pins. However, 8-bit mode is best used when speed is required in an application and there are at least 10 I/O pins available.

The sketch begins by including the LiquidCrystal library. The Arduino community has a library called LiquidCrystal which makes programming of LCD modules less difficult. You can find more information about the library on Arduino’s official website.

First we create a LiquidCrystal object. This object uses 6 parameters and specifies which Arduino pins are connected to the LCD’s RS, EN, and four data pins.

In the ‘setup’ we call two functions. The first function is begin(). It is used to specify the dimensions (number of columns and rows) of the display. If you are using a 16×2 character LCD, pass the 16 and 2; If you’re using a 20×4 LCD, pass 20 and 4. You got the point!

After that we set the cursor position to the second row by calling the function setCursor(). The cursor position specifies the location where you want the new text to be displayed on the LCD. The upper left corner is assumed to be col=0, row=0.

There are some useful functions you can use with LiquidCrystal objects. Some of them are listed below:lcd.home() function is used to position the cursor in the upper-left of the LCD without clearing the display.

lcd.scrollDisplayRight() function scrolls the contents of the display one space to the right. If you want the text to scroll continuously, you have to use this function inside a for loop.

lcd.scrollDisplayLeft() function scrolls the contents of the display one space to the left. Similar to above function, use this inside a for loop for continuous scrolling.

If you find the characters on the display dull and boring, you can create your own custom characters (glyphs) and symbols for your LCD. They are extremely useful when you want to display a character that is not part of the standard ASCII character set.

As discussed earlier in this tutorial a character is made up of a 5×8 pixel matrix, so you need to define your custom character within that matrix. You can use the createChar() function to define a character.

To use createChar() you first set up an array of 8 bytes. Each byte in the array represents a row of characters in a 5×8 matrix. Whereas, 0 and 1 in a byte indicate which pixel in the row should be ON and which should be OFF.

CGROM is used to store all permanent fonts that are displayed using their ASCII codes. For example, if we send 0x41 to the LCD, the letter ‘A’ will be printed on the display.

CGRAM is another memory used to store user defined characters. This RAM is limited to 64 bytes. For a 5×8 pixel based LCD, only 8 user-defined characters can be stored in CGRAM. And for 5×10 pixel based LCD only 4 user-defined characters can be stored.

Creating custom characters has never been easier! We have created a small application called Custom Character Generator. Can you see the blue grid below? You can click on any 5×8 pixel to set/clear that particular pixel. And as you click, the code for the character is generated next to the grid. This code can be used directly in your Arduino sketch.

Your imagination is limitless. The only limitation is that the LiquidCrystal library only supports eight custom characters. But don’t be discouraged, look at the bright side, at least we have eight characters.

In setup we need to create custom character using createChar() function. This function takes two parameters. The first parameter is a number between 0 and 7 to reserve one of the 8 supported custom characters. The second is the name of the array.

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?

there is a bit more but i"ll leave that for you to look into. in a more sophisticated IDE you normally can right click to a sub menu that will take you to the definition. it"s a great way to help you get a deeper understanding of how things work.0

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?

The Displaytech 162H series is a lineup of 16x2 character LCD modules. These modules have an 84x44 mm outer dimension with a 66x16 mm viewing area on the display. The 162H 16x2 LCD displays are available in STN or FSTN LCD modes with or without an LED backlight. The backlight color options include yellow green, white, blue, pure green, or amber color. Get a free quote direct from Displaytech for a 16x2 character LCD display from the 162H series.

The Displaytech 162J series is a lineup of 16x2 character LCD modules. These modules have an 80x36 mm outer dimension with 66x16 mm viewing area on the display. The 162J 16x2 LCD displays are available in STN or FSTN LCD modes with or without an LED backlight. The backlight color options include yellow green, white, blue, pure green, or amber color. Get a free quote direct from Displaytech for a 16x2 character LCD display from the 162J series.

The CFA533-***-KC series is a 16x2 I2C LCD with keypad. The I2C interface allows you to use just two lines (SDA & SCL) to have bi-directional communication with the I2C LCD. Other devices can also share those two I2C control lines with the LCD. Only 4 wires are needed to connect this I2C LCD: power, ground, SDA (I2C Serial DAta) and SCL (I2C Serial CLock).

The CFA533 can run on 3.3v to 5.0v directly, with no changes needed, so you do not need to do any level translation between your embedded processor and the I2C LCD. Simply power the CFA533 from the same supply as your processor and the I2C signal levels will match up.

Using only one address on your I2C bus, you can add all the elements that you need for your front panel. The CFA533 I2C LCD can also read up to 32 DS18B20 digital temperature sensors, giving you an easy way to integrate temperature sensing over the I2C bus. No additional firmware or pins are needed on the host system.

This CFA533-TFH variant features crisp dark letters against a white, backlit background. The keypad has a matching white LED backlight. Since the LCD is a backlit positive FSTN, the CFA533-TFH I2C LCD is readable in direct sunlight, as well as complete darkness.

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The diagram of the pins on the LCD we use is as follows. We have 16 pins on our LCD screen. Depending on the screen we are going to use, the pins can be on the top, bottom, or both sides of the screen. Some very rare screens have 14 pins because there is no backlighting light. Pins 15 and 16 are used to light up the backlight on displays with display lighting. The backlights are separate from the LCD, so we can use the pin of the backlight by plugging it into a digital port. The connections from each pin to the Arduino will be the same, but it can arrange differently you can pins via the LCD. You can look at the LCD’s datasheet for this.

Warning: You may need to solder a 16-pin cap to your LCD before connecting it to the breadboard. Follow the diagram below to connect the LCD to your Arduino:

If you want, you can not use the potentiometer, we can adjust the contrast of the backlight with the potentiometer, but if you do not want, you can use the backlight by giving the V0 pin 5 volts directly. If you’d like to see the diagram more clearly, click here.

All the codes we will see are the LiquidCrystal library that comes with the Arduino IDE. We will try many features with this library, of course. Since it is a giant guide, we cannot pass without telling the LiquidCrystal library.