lcd module can be initialized by quotation

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:

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:

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:

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.

From Figure 3 above we can see that the DDRAM controller should have a memory map of 104 bytes (00H to 67H = 68H = 104D), but the location that can be used is only 80 bytes 00H-27H (40 bytes) and 40H-67H (40 bytes); Note that the 28H-3FH address (24 location) is not visible.

LCD connected to this controller will adjust itself to the memory map of this DDRAM controller; each location on the LCD will take 1 DDRAM address on the controller. Because we use 2 × 16 type LCD, the first line of the LCD will take the location of the 00H-0FH addresses and the second line will take the 40H-4FH addresses of the controller DDRAM; so neither the addresses of the 10H-27H on the first line or the addresses of the 50H-67H on the second line on DDRAM is used.

To be able to display a character on the first line of the LCD, we must provide written instructions (80h + DDRAM address where our character is to be displayed on the first line) in the Instruction Register-IR and then followed by writing the ASCII code of the character or address of the character stored on the CGROM or CGRAM on the LCD controller data register, as well as to display characters in the second row we must provide written instructions (C0H + DDRAM address where our character to be displayed on the second line) in the Instructions Register-IR and then followed by writing the ASCII code or address of the character on CGROM or CGRAM on the LCD controller data register.

As mentioned above, to display a character (ASCII) you want to show on the LCD, you need to send the ASCII code to the LCD controller data register-DR. For characters from CGROM and CGRAM we only need to send the address of the character where the character is stored; unlike the character of the ASCII code, we must write the ASCII code of the character we want to display on the LCD controller data register to display it. For special characters stored on CGRAM, one must first save the special character at the CGRAM address (prepared 64 addresses, namely addresses 0–63); A special character with a size of 5 × 8 (5 columns × 8 lines) requires eight consecutive addresses to store it, so the total special characters that can be saved or stored on the CGRAM addresses are only eight (8) characters. To be able to save a special character at the first CGRAM address we must send or write 40H instruction to the Instruction Register-IR followed by writing eight consecutive bytes of the data in the Data Register-DR to save the pattern/image of a special character that you want to display on the LCD [9, 10].

We can easily connect this LCD module (LCD + controller) with MCS51, and we do not need any additional electronic equipment as the interface between MCS51 and it; This is because this LCD works with the TTL logic level voltage—Transistor-Transistor Logic.

Pins 7–14 (8 Pins) of the display function as a channel to transmit either data or instruction with a channel width of 1 byte (D0-D7) between the display and MCS51. In Figure 6, it can be seen that each Pin connected to the data bus (D0-D7) of MCS51 in this case P0 (80h); P0.0-P0.7 MCS-51 connected to D0-D7 of the LCD.

Pins 4–6 are used to control the performance of the display. Pin 4 (Register Select-RS) is in charge of selecting one of the 2 display registers. If RS is given logic 0 then the selected register is the Instruction Register-IR, otherwise, if RS is given logic 1 then the selected register is the Data Register-DR. The implication of this selection is the meaning of the signal sent down through the data bus (D0-D7), if RS = 0, then the signal sent from the MCS-51 to the LCD is an instruction; usually used to configure the LCD, otherwise if RS = 1 then the data sent from the MCS-51 to the LCD (D0-D7) is the data (object or character) you want to display on the LCD. From Figure 6 Pin 4 (RS) is connected to Pin 16 (P3.6/W¯) of MCS-51 with the address (B6H).

Pin 5 (R/W¯)) of the LCD does not appear in Figure 6 is used for read/write operations. If Pin 5 is given logic 1, the operation is a read operation; reading the data from the LCD. Data will be copied from the LCD data register to MCS-51 via the data bus (D0-D7), namely Pins 7–14 of the LCD. Conversely, if Pin 5 is given a voltage with logical 0 then the operation is a write operation; the signal will be sent from the MCS51 to LCD through the LCD Pins (Pins 7–14); The signal sent can be in the form of data or instructions depending on the logic level input to the Register Select-RS Pin, as described above before if RS = 0 then the signal sent is an instruction, vice versa if the RS = 1 then the signal sent/written is the data you want to display. Usually, Pin 5 of the LCD is connected with the power supply GND, because we will never read data from the LCD data register, but only send instructions for the LCD work configuration or the data you want to display on the LCD.

Pin 6 of the LCD (EN¯) is a Pin used to enable the LCD. The LCD will be enabled with the entry of changes in the signal level from high (1) to low (0) on Pin 6. If Pin 6 gets the voltage of logic level either 1 or 0 then the LCD will be disabled; it will only be enabled when there is a change of the voltage level in Pin 6 from high logic level to low logic level for more than 1000 microseconds (1 millisecond), and we can send either instruction or data to processed during that enable time of Pin 6.

Pin 3 and Pin 15 are used to regulate the brightness of the BPL (Back Plane Light). As mentioned above before the LCD operates on the principle of continuing or inhibiting the light passing through it; instead of producing light by itself. The light source comes from LED behind this LCD called BPL. Light brightness from BPL can be set by using a potentiometer or a trimpot. From Figure 6 Pin 3 (VEE) is used to regulate the brightness of BPL (by changing the current that enters BPL by using a potentiometers/a trimpot). While Pin 15 (BPL) is a Pin used for the sink of BPL LED.

4RSRegister selector on the LCD, if RS = 0 then the selected register is an instruction register (the operation to be performed is a write operation/LCD configuration if Pin 5 (R/W¯) is given a logic 0), if RS = 1 then the selected register is a data register; if (R/W¯) = 0 then the operation performed is a data write operation to the LCD, otherwise if (R/W¯) = 1 then the operation performed is a read operation (data will be sent from the LCD to μC (microcontroller); it is usually used to read the busy bit/Busy Flag- BF of the LCD (bit 7/D7).

5(R/W¯)Sets the operating mode, logic 1 for reading operations and logic 0 for write operations, the information read from the LCD to μC is data, while information written to the LCD from μC can be data to be displayed or instructions used to configure the LCD. Usually, this Pin is connected to the GND of the power supply because we will never read data from the LCD but only write instructions to configure it or write data to the LCD register to be displayed.

6Enable¯The LCD is not active when Enable Pin is either 1 or 0 logic. The LCD will be active if there is a change from logic 1 to logic 0; information can be read or written at the time the change occurs.

For an I2C LCD display to work, the I2C address and the I2C backpack to LCD pin mapping must be correct. If the library default settings for either or both are not correct the LCD will not work. You can try to figure out the right pin mapping and use an I2C scanner to find the address, but if you install and use the hd44780 library that is done automatically by the library.

Install the hd44780 library. The hd44780 library is the best available for I2C LCDs. The library is available in the Library Manager. Go to Library Manager (in the IDE, Sketch, Include Libraries, Manage Libraries) and in the Topics dropdown choose Display and in the Filter your search box enter hd44780. Select and install the hd44780 library by Bill Perry.

The class that you want to use is the hd44780_I2Cexp class. There are examples to show how to use the library. The nice thing about the hd44780 library is that it will autodetect the I2C address and the I2C backpack to LCD pin mapping.

I am facing some problem in LCD interfacing. Im displaying some characters like "ABCDEX" 4bit mode on TIVAC123GH6PM. It works fine for some time after that start showing some garbage characters.what can be problem. Also I tested with single character like "A" it display fine but when I replaced it with "W" it shows some garbage character. some more characters like "G" ,"K" also shows garbage. What can be problem.It LCD got corrupted?Also LCD Back-light flickering.

This article includes everything you need to know about using acharacter I2C LCD with Arduino. I have included a wiring diagram and many example codes to help you get started.

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_I2C library.

Once you know how to display text and numbers on the LCD, I suggest you take a look at the articles below. In these tutorials, you will learn how to measure and display sensor data on the LCD.

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Each rectangle is made up of a grid of 5×8 pixels. Later in this tutorial, I will show you how you can control the individual pixels to display custom characters on the LCD.

They all use the same HD44780 Hitachi LCD controller, so you can easily swap them. You will only need to change the size specifications in your Arduino code.

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

Note that an Arduino Uno with the R3 layout (1.0 pinout) also has the SDA (data line) and SCL (clock line) pin headers close to the AREF pin. Check the table below for more details.

After you have wired up the LCD, you will need to adjust the contrast of the display. On the I2C module, you will find a potentiometer that you can turn with a small screwdriver.

Note that counting starts at 0 and the first argument specifies the column. So lcd.setCursor(2,1) sets the cursor on the third column and the second row.

Next the string ‘Hello World!’ is printed with lcd.print("Hello World!"). Note that you need to place quotation marks (” “) around the text since we are printing a text string.

The example sketch above shows you the basics of displaying text on the LCD. Now we will take a look at the other functions of the LiquidCrystal_I2C library.

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.

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.

We can directly assign a string literal to a character array keeping in mind to keep the array size at least one more than the length of the string literal that will be assigned to it.

It is also possible to directly assign a string literal to a character array without any size. The size gets determined automatically by the compiler at compile time.charstr[] ="Scaler.";

A data set is the internal data structure that holds rows of values for the table field. An initialized table field can have many rows in its data set, even though not all can be displayed. For a full discussion of table fields and data sets, see Table Fields.

Formname specifies the name of the form in which the table field identified by tablename is displayed. You can express either name as a quoted or unquoted character string or as a program variable.

The tablemode sets the table field"s display mode. It must be a quoted or unquoted character string or program variable that evaluates to one of the following values:

In this mode, the user can only browse the contents of the table field by scrolling through the values in the data set. This mode is normally used with table fields that merely display data or when all changes to the data are made by means of menu operations.

In this mode, the user can scroll through the values in the data set and change the data displayed. However, the user cannot add rows to the end of the data set. This mode is useful in applications that display a series of records for possible modifications by the user.

This mode has all the capabilities of the fill mode, but also allows the user to enter comparison operators (for example, <> or >=,) which can be retrieved into program variables. Query mode is useful for allowing a user to specify parameters for a database retrieval.

The mode of the table field is normally independent of the mode of its form. However, if the form is displayed in read mode, then the table field behaves as if it is in read mode also. The real mode of the table has not been lost, however.

The optional column list is used to define hidden columns for the table field. Hidden columns are columns of data that are not displayed on the form and are therefore invisible and inaccessible to the user, but which can be accessed by the program in the same way the program accesses displayed columns. A columnname can be any valid Ingres name of up to 32 bytes and can be expressed as a quoted or unquoted character string literal or a program variable. The column"s format defines its data type and length. The format can be any legal Ingres data type. See your query language reference guide for a complete list of legal data types.

The format can include the with null clause to specify that the hidden column is nullable or the not null clause to specify a non-nullable hidden column. Not null implies not null with default. By default, a hidden column is non-nullable.

The inittable statement can appear at any point after the form that contains the table field has been declared. However, because a table field cannot have a data set associated with it until inittable is performed, most applications execute the inittable statement before displaying the form containing the table field.

After reading the last couple of articles you should now know what JavaScript is, what it can do for you, how you use it alongside other web technologies, and what its main features look like from a high level. In this article, we will get down to the real basics, looking at how to work with the most basic building blocks of JavaScript — Variables.

To gain familiarity with the basics of JavaScript variables.Throughout this article, you"ll be asked to type in lines of code to test your understanding of the content. If you are using a desktop browser, the best place to type your sample code is your browser"s JavaScript console (see What are browser developer tools for more information on how to access this tool).A variable is a container for a value, like a number we might use in a sum, or a string that we might use as part of a sentence.Let"s look at a simple example:

You may not fully understand the syntax we are using (yet!), but you should be able to get the idea. If we didn"t have variables available, we"d have to ask the reader for their name every time we needed to use it!

One special thing about variables is that they can contain just about anything — not just strings and numbers. Variables can also contain complex data and even entire functions to do amazing things. You"ll learn more about this as you go along.

Note: We say variables contain values. This is an important distinction to make. Variables aren"t the values themselves; they are containers for values. You can think of them being like little cardboard boxes that you can store things in.

Note: Don"t confuse a variable that exists but has no defined value with a variable that doesn"t exist at all — they are very different things. In the box analogy you saw above, not existing would mean there"s no box (variable) for a value to go in. No value defined would mean that there is a box, but it has no value inside it.Once you"ve declared a variable, you can initialize it with a value. You do this by typing the variable name, followed by an equals sign (=), followed by the value you want to give it. For example:

Try going back to the console now and typing in these lines. You should see the value you"ve assigned to the variable returned in the console to confirm it, in each case. Again, you can return your variable values by typing their name into the console — try these again:

A couple of simple differences are explained below. We won"t go into all the differences now, but you"ll start to discover them as you learn more about JavaScript (if you really want to read about them now, feel free to check out our let reference page).

For a start, if you write a multiline JavaScript program that declares and initializes a variable, you can actually declare a variable with var after you initialize it and it will still work. For example:

For these reasons and more, we recommend that you use let in your code, rather than var. There is no longer any reason to use var, as it has been supported since Internet Explorer 11.

// As two inputs: both succeedOnce a variable has been initialized with a value, you can change (or update) that value by giving it a different value. Try entering the following lines into your console:

myAge = 40;You can call a variable pretty much anything you like, but there are limitations. Generally, you should stick to just using Latin characters (0-9, a-z, A-Z) and the underscore character.

A safe convention to stick to is so-called "lower camel case", where you stick together multiple words, using lower case for the whole first word and then capitalize subsequent words. We"ve been using this for our variable names in the article so far.

One last point: you also need to avoid using JavaScript reserved words as your variable names — by this, we mean the words that make up the actual syntax of JavaScript! So, you can"t use words like var, function, let, and for as variable names. Browsers recognize them as different code items, and so you"ll get errors.

Try creating a few more variables now, with the above guidance in mind.There are a few different types of data we can store in variables. In this section we"ll describe these in brief, then in future articles, you"ll learn about them in more detail.

So far we"ve looked at the first two, but there are others.You can store numbers in variables, either whole numbers like 30 (also called integers) or decimal numbers like 2.456 (also called floats or floating point numbers). You don"t need to declare variable types in JavaScript, unlike some other programming languages. When you give a variable a number value, you don"t include quotes:

let dolphinGoodbye = "So long and thanks for all the fish";Booleans are true/false values — they can have two values, true or false. These are generally used to test a condition, after which code is run as appropriate. So for example, a simple case would be:

This is using the "less than" operator (<) to test whether 6 is less than 3. As you might expect, it returns false, because 6 is not less than 3! You will learn a lot more about such operators later on in the course.An array is a single object that contains multiple values enclosed in square brackets and separated by commas. Try entering the following lines into your console:

You"ll learn a lot more about arrays in a future article.In programming, an object is a structure of code that models a real-life object. You can have a simple object that represents a box and contains information about its width, length, and height, or you could have an object that represents a person, and contains data about their name, height, weight, what language they speak, how to say hello to them, and more.

We won"t be looking at objects any more for now — you can learn more about those in a future module.JavaScript is a "dynamically typed language", which means that, unlike some other languages, you don"t need to specify what data type a variable will contain (numbers, strings, arrays, etc.).

Try entering the four lines above into your console one by one, and see what the results are. You"ll notice that we are using a special operator called typeof — this returns the data type of the variable you type after it. The first time it is called, it should return string, as at that point the myNumber variable contains a string, "500". Have a look and see what it returns the second time you call it.As well as variables, you can declare constants. These are like variables, except that:

Note that although a constant in JavaScript must always name the same value, you can change the content of the value that it names. This isn"t a useful distinction for simple types like numbers or booleans, but consider an object:

You can update, add, or remove properties of an object declared using const, because even though the content of the object has changed, the constant is still pointing to the same object:

console.log(bird.species); // "Striated Caracara"If you can"t do as much with const as you can with let, why would you prefer to use it rather than let? In fact const is very useful. If you use const to name a value, it tells anyone looking at your code that this name will never be assigned to a different value. Any time they see this name, they will know what it refers to.

This means that if you can initialize a variable when you declare it, and don"t need to reassign it later, make it a constant.You"ve reached the end of this article, but can you remember the most important information? You can find some further tests to verify that you"ve retained this information before you move on — see Test your skills: variables.By now you should know a reasonable amount about JavaScript variables and how to create them. In the next article, we"ll focus on numbers in more detail, looking at how to do basic math in JavaScript.Found a content problem with this page?Edit the page on GitHub.