lcd display character set quotation

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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.

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.

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:

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 (°):

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.

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.

OK, this is the sketch that I used to try out user-defined characters on a four-row, 20 character LCD. If you have a two-row LCD, you"ll have to change the calls to "drawbar" in the main loop. You"ll need a potentiometer with the track connected to 0V and 5V, and the wiper connected to analog in 0. Turn (or slide) the pot to see the bar extend across the LCD. The crucial command to the LCD is 0x40, which is used to position the "cursor" in the CGRAM, which is where the user-defined characters are stored. A call to "home" is required after defining the characters, to put the cursor back into the main display memory. All this is documented in the HD44780 data sheet.

ERM2004FS-3 is small size 20 characters wide,4 rows character lcd module,SPLC780C controller (Industry-standard HD44780 compatible controller),6800 4/8-bit parallel interface,single led backlight with white color included can be dimmed easily with a resistor or PWM,fstn-lcd positive,black text on the white color,high contrast,wide operating temperature range,wide view angle,rohs compliant,built in character set supports English/Japanese text, see the SPLC780C datasheet for the full character set, It"s optional for pin header connection,5V or 3.3V power supply and I2C adapter board for arduino.

Character based LCD displays are great: they are inexpensive, and it is rather simple to use them compared to graphical displays. Yes, they only can display text and custom symbols, but this is usually what I need. And pretty much all character displays are using the Hitachi HD44780 protocol, so it is a de-facto industry standard.

These displays have one big disadvantage: they need to be compatible with the original Hitachi interface and protocol. First display were mostly one line only, and had only few characters, typically up to 16. The protocol worked either with one or two lines on the display. Today’s display have usually two lines, with 16 characters. But what if I need more?

These HD44780 displays can run in 4bit or 8bit mode, and in the smallest configuration (4bit mode) the connection to the microcontroller only needs 6 wires:

The original protocol had a big problem: there is no handshaking between microcontroller and display. If the microcontroller writes to the display, it needs to wait until the display has finished the operation until a new write operation can start. So the micrcontroller needs to wait some time, depending on the display speed. To overcome this problem, later displays had added the R/W (Read/Write) signal which allows the microcontroller to read the status from the display (if the display is ready to accept new data). So if you consider to use a display, make sure it has that R/W line implemented.

So writing at address 0x00 would be the first character on line 1, 0x01 the second, and so on. Writing at address 0x40 would be the first character on the second line, and so on. That would allow up to 64 characters per line. A 16-character display would show the characters e.g. from address 0x00-0x0F. The other bytes in the address map could be used to ‘scroll’ the text to the right/left using special display commands:

As this feature has not been used much, and there was a bigger customer needs for having 4 lines of text, some vendors decided to change the memory map to support 4 lines (see “Character LCD with 4 Lines”):

If I want now to have 4 lines with more than 16 characters, something different is needed. My display driver (LCDHTA, see “HD44780 2×16 Character Display for Kinetis and Freedom Board“) worked fine, but not for a 4×40 display which was used by a reader of this blog :-(: the NewHaven NHD-0440WH-ATFH-JT Display:

Until I realized: they have put 2 display controller together! This display is not really a 4×40 character display, it is two 2×40 displays in a single display packaging :-). This is the same as if I would combine two displays on the same bus like this:

As I did not had the Newhaven 4×40 display available to verify the driver, I wired two 2×16 displays together. And with this, I was able to build a 4×16 (potentially 4×64) character display:

The Hitachi HD44780 is very common and can be considered as ‘industry standard’. But as with any standards, it comes with limitations, and standards sometimes make it hard to move the technology to the next level. And sometimes it causes kind of strange solutions as creating a 4 line display with two display controllers on it. Switching the Ex lines I can now support up to for 4 lines and up to 64 characters for each line. And if needed, I can extend that concept for more lines/displays.

Characters variable values can be equal to almost any single letter, number or punctuation mark you can type with your keyboard and some special characters that you probably can’t even make using your keyboard! Here’s what we’ll be covering on this page:

ASCII Values ASCII stands for American Standard Code for Information Interchange. Inside of Sparki’s little robotic brain all the characters get converted to the ASCII value when Sparki is doing any calculations or actions with a character. That explains why you can get the value ‘a’ by creating a character variable with the value ‘a’ or 97. Check out the chart below to get comfortable with characters before we move on.

This will create a variable named “roo.” The type of this variable will be a character. Since you didn’t give the variable a value when you first created it the value of the variable is automatically ‘null’. Null is a special character that means empty. The ASCII value of ‘null’ is 0.

Assigning Values (Putting Information in the Character Variables) There are two different ways you can assign values to a character variable. One way uses the letters, numbers and punctuation marks that you will see on Sparki’s LCD screen, other uses the ASII values that you can find in the chart above. Here’s how you assign a value to a character variable using the first method. Notice how the ‘a’ is wrapped in single-quotes.That’s important. Double quotes do not mean a single character, they indicate a sentence or word. I’m sure you’re also familiar with the semicolon by now, it’s our ever present friend that tells Sparki the line of code is finished and ready for action.

Displaying the Character Variables So now that you know how to create character variables and assign them values let’s learn how to use them with Sparki! You’ll learn later how to use characters during communication but for now we’re going to make them show up on the LCD screen. This is useful for sending messages, displaying data or just having fun. However, before we can display the characters on screen we’ll need to write a couple commands to make the LCD screen work.

} Let’s go over these three commands quickly so that you feel comfortable with all the code we are using.The sparki.clearLCD( ) command tells Sparki to clear the LCD. If we didn’t use this command then the characters that were drawn on the screen before would stay there and as more and more characters got drawn on the screen it would become harder and harder to see the new characters since they would be muddled together with all the other previous characters.

The sparki.updateLCD( ) tells Sparki to put whatever code that was printed to the LCD on the screen. This is the line of code that actually makes the characters visible. Any print commands that we use to try and display characters after this command will never show up on the LCD.

delay(1000) tells Sparki to wait 1000 milliseconds (or one second) before continuing with the code. The reason this line of code is in our program is because if we were displaying different data each time through loop then the characters displayed on Sparki’s LCD would go by so quickly we wouldn’t even be able to see them! These are just the basics needed to get started with the LCD. If you want more information about the LCD screen click here. Now that you feel comfortable with the basic LCD commands let’s display some characters. We’ll be using the sparki.println( ) command to display our characters. This command simply prints whatever is inside its parentheses to the LCD screen and then goes to the next line on the LCD in case there will be more sparki.println( ) commands. Let’s use some code to scroll through all the possible character values and display their ASCII values as well-

Doing Math with Character Variables Because characters are integer numbers on the inside, you can add to them (or subtract, multiply or divide) to change them. Try it out:

Next Step: But characters don’t sound very useful on their own. To spell things, we need to have more than one of them in a row and there must be an easier way using a whole bunch of sparki.print( ) commands. How do we do that? With Arrays!

Character LCD Displays (aka Alphanumeric) are one of the most common display technologies available and for that reason we hold inventory for samples and prototypes in our Chandler, Arizona location.

These displays have been in use for many years, and in some ways the technology has become a commodity, but it is important to select the best options to fit your design. There are many details concerning this technology, including: fluid type, operating voltage, controller/drivers and other key details that can make your design excel or under-perform.

Our team of LCD specialists can assist you in selecting the best options so that your design is able to meet your needs and at a cost that is within your budget. Call today with any questions.

These displays are used in applications such as change machines, measurement devices, and data loggers. The module has the ability to display letters, numbers and punctuation marks.

One reason for the popularity of Character LCD displays is that they are equipped with a controller/driver chip containing a built in character (or font) table.

The table holds preloaded letters, numbers, and punctuation for each language. The font table allows the designer to request any character by addressing (selecting) the number of that character. In other words, the letter capital ‘T’ may be assigned the number 31 and the “&” symbol could be assigned number 141. This eliminates the work required to create each charter from scratch and reduces the amount of time necessary to program the LCD module.

The LCD you choose for your new design sets the perceived value of your product. Think about it: The first thing your customer looks at when they are deciding whether to purchase your product, is the LCD display. If it looks good, then your product looks good.

Negative mode displays are popular for new designs since they stand out. Negative mode means the background is a darker color, like black or blue and the characters/icons/segments are a lighter color such as: White, Red or Green.

The opposite of a negative mode is positive mode where the background is a lighter color such as yellow/green or grey and the characters/icons/segments are a darker color like black or dark blue.

Negative mode displays must have a backlight on all the time to be readable. The challenge is that the LED backlight will draw/drain 10 times more power than the LCD without a backlight. So, if this is a battery application, it is best to stick with a positive mode.

Positive mode displays are readable without a backlight if there is enough ambient light. The LCD without a backlight will draw around 1uA. LED backlights can draw as little as 15mA up to 75mA or more depending on the number and brightness of the LEDs.

The first question to answer is ‘what size of LCD?’ The larger the display the more information that can be displayed and the larger the characters can be. We recommend you choose one of the standard sizes on this page to reduce cost and lead time. Focus Display Solutions (aka FocusLCDs) carries many of the industry standard sizes in inventory and may be able to ship the same day.

Character LCD Displays are built in standard configurations such as 8×1, 20×2 and 40×4. The two numbers identify the number of characters in each row and then the number of rows. An example of this is a 20×2 which means there are 20 characters in each row and there are two rows. This will provide you a total of 40 characters. The more characters there are on the display, the more drivers are required to drive the LCD. The controller and drivers are included with the LCD.

Note: It is possible to program the software to scroll your letters and numbers across the screen, allowing you to choose a smaller sized LCD and still display all your information.

The cost of character displays is driven more by the size of the glass, then by the number of characters. A larger 8×1 can be more expensive than a small 16×2.

It is possible to custom build a unique combination such as a 12×2 or a 16×8. This would be considered a custom LCD and would require a one-time tooling cost and possibly a higher MOQ. Go to our

Character LCD modules are available in two temperature ranges, Normal (for indoor use) and Extended (for outdoor use). The outdoor version will continue to operate down to -30C. The cost difference between normal and wide (extended) temperature range is 5% to 7% higher for the extended versions. In most cases, if cost is not critical, we recommend that you incorporate the wider temperature version.

There are three types of backlights available for a character LCD module: No backlight; LED; or EL backlight. Before introducing the various backlight options, it is helpful to cover two terms that are common for backlights: NITs and half-life.

Engineers designing a battery powered product may request a character module with no backlight since the backlight draws more than ten times (10x) the power required for the LCD alone. The goal with a battery powered product is to conserve power and extend the life-time of the battery.

If the product needs to be readable in the dark or low light conditions, then it will be necessary to attach a backlight of one type or another. The best way to conserve power is to keep the amount of time the backlight is on to a minimum. Turn off the backlight as soon as the user no longer needs it. This is a common practice in cell phones. The backlight turns off a few seconds after the number is dialed or the phone is answered. The person using the phone will continue to talk, but the display will be dark.

DC Current – LEDs are driven by DC (Direct Current), which is the same type of power required for the character LCD logic voltage. Also, batteries supply DC which makes it easy to integrate the LED backlight with a battery. EL backlights require an AC (Alternating Current) to operate. The AC signal needs to be generated by an inverter. The added inverter increases the cost of the display and produces electrical noise that can interfere with neighboring circuits.

Character LCDs that include an EL (ElectroLuminescent) backlight are not as common and their popularity is decreasing. EL backlights are AC driven which requires an inverter to be supplied by the customer or attached to the LCD. Their half-life is rated at 3K hours which makes this a poor choice for products where the backlight will be on all the time. Their MOQ (Minimum Order Quantities) have increased in the last few years. At this time there is a 500 piece MOQ.

There are some key advantages to EL backlights. They are very thin, around one to two millimeters in thickness. And they provide a very even flow of light. We carry inventory on a few EL character displays, but the majority of the character displays we sell are LED.

A character LCD is constructed by placing the nematic fluid between two layers of ITO (Indium tin oxide) glass. The function of the fluid is to either block or allow light to pass through.

A TN (Twisted Nematic) monochrome LCDs is the lowest cost option. TN does not provide a very sharp contrast and has a smaller viewing angle then STN or FSTN. A smaller viewing angle means the display is readable if you look directly at it, but if you rotate it more than 40 degrees in either direction, the characters will be difficult to read.

STN (Super Twisted Nematic) fluid is the most popular option. It provides a sharper contrast and a wider viewing angle than TN. Below is a photo of a STN 16 x2 character display.

FSTN monochrome character LCD displays are assembled by taking the STN fluid and adding a film or retardation coating to the glass. This produces a sharper contrast than STN. FSTN is more popular on higher end products such as medical applications. Below is a photo of a FSTN 16×2 monochrome LCD

There are three types of polarizers: Reflective; Transflective; and Transmissive. The correct polarizer is determined by the various lighting conditions your character LCD display will operate in.

The job of the polarizer is to allow some light to pass through and some of the light to be reflected. Depending on where your display will be operating, will decide which polarizer to choose. There is no cost difference between the three polarizers. Below is a quick summary:

The reflective polarizer is basically a mirror. It will reflect 100% of the ambient light and is ideal for displays operating in direct sunlight or in situations with very bright indoor lights.

A reflective polarizer cannot be used with a LED backlight or EL backlight since it will not allow any of the light to pass through, but it is possible to use with a LED edge-lit or side-lit display. An advantage of an edge-lit display is that it is thinner than a LED backlight, but not as thin as a display equipped with an EL backlight.

A Transflective polarizer is the most popular of the three options and works best with a display that requires the backlight to be on some of the time and off some of the time. It does not perform as well in direct sunlight as a reflective polarizer, but is sufficient in most cases.

The Transmissive polarizer is used when the backlight is on all the time. This is not the best option for battery powered products, but provides a brighter backlight. This polarizer must be used for displays that run in negative mode. Negative mode is when the characters are light colored and the background is a dark.

V Logic is the voltage used to drive an LCD and draws very little current, somewhere around 1mA or less. Character displays can be driven with a VL at 3.3V or 5V.

V LED is the voltage used to drive the LED backlight only. This can be 3.3V or 5V. LED backlights can draw up to ten times (10X) the amount of current of just the LCD alone (VLCD). If your product is a battery application, the backlight should be turned off when not in use. Or build in a sensor that only turns it on in the dark.

Is it possible to drive the LCD and the LED backlight from the same connection, but not recommended since interference from the LED backlight could affect the performance of the LCD.

A key advantage of character LCDs over multicolor technology such as TFT (Thin Film Transistor) and OLED (Organic Light Emitting Diodes) it their low thirst for current.

TFTS and OLEDs require power to generate light to be readable. In many cases, their backlight needs to be even brighter in direct sunlight. This could draw 50mA or more depending on the size and brightness of the display.

When the ambient temperature of the display drops too low, the display’s performance suffers. The colder the fluid in the display, the slower the response. At some point, the display freezes up and the characters no longer change.

As long as the temperature doesn’t drop too low, there will be no damage to the display, and it will return to normal operation when the temperature rises.

This is a much more affordable solution. A small PCB (Printed Circuit Board) is attached to the back of the LCD. The board is populated with several quarter watt resistors in series that generate heat. This option draws a great deal of power. In fact, it draws more than most LED backlights.

Believe it or not, LEDs do generate heat, but nothing close to resistors or heater film. In some cases, it is enough to give the display a little extra warmth to keep it operating when the temperature drops below its threshold.

Nothing saves heat and power like insulation. Putting your LCD into something that breaks the wind and holds in the heat, will save your batteries. Many times, a protected display will continue to operate even when the temperature drops far below the threshold. This should always be the first step taken when worrying about display functionality at low temperatures. Once your product is insulated, the heat producing options noted above can be implemented.

There are three fluid types used in character LCDs: TN, STN and FSTN. TN operates the best at colder temperatures and offers a faster response time. TN does not provide the wide viewing range found in STN and FSTN, but is sufficient for most industrial uses.

The five most common types of LCD technology are: Segment, Character, Graphic, TFT and OLED. Character and Segment are the least likely options to be discontinued. They have been around for many years and are still very popular.

The displays are made up of small squares that contain a 5x8, 7x10 or 16x16 dot matrix configurations. That means there are 5 dots across and 8 dots up for a total of 40 dots. Each dot is individuality addressed on or off to produce any letter or number.

Contrast adjust. Used to lighten or darken the character with respect to the background color. This is done by adjusting the voltage (through a potentiometer or software) between max logic voltage and ground

Used to read or write the data being transferred between the LCD and the microprocessor. Tie this to ground if you only plan to write data for one-way communications.

DB 0. Most character LCDs have eight (8) data bits for faster transfer. But can operate on just four (4) data bits if you are running low on I/O (In/Outs) pins.

Positive connection of the LED backlight or side lit. The voltage could range from 5V or 3.3V. Not all character LCDs contain a LED backlight. In this case, the two pins are no connect.

Polarity is an issue with LED backlights, since they are DC (Direct Current). That means positive must connect to positive. Half of the character LCDs have pin 15 as positive and 16 as ground. The other half are reversed. If you need the polarity reversed, there is a jumper on the back of the PCB to switch polarity.

This page contains a partial list of our standard displays. Simply choose the number of characters, the size of the display and the color combination that will meet your needs. If you need a size not listed on this page, please call us. We can still supply it to you.

Our lead time on standard Character LCD displays – that are not in stock – range from five to seven weeks. This rapid lead time is due to the fact that we do not ship LCD’s via boat, but FedEx Air. By shipping via FedEx Air, we receive the LCD glass within four to five days after it is completed, compared to shipping by boat which can add several additional weeks to your lead time.

Don’t see the exact display you want on this page? Focus Display Solutions can supply you a display to match the exact configuration you want, even if it is not in our current inventory.

The cost to design and tool up a custom replacement LCD is much less than the cost associated with retooling a case or having to redesign the customer’s PCB to accept a different LCD. The customer may also need the exact display to repair units that are in the field.

This custom character design allows the customer to avoid any redesign cost or delays in the manufacturing of their product and to offer replacement displays for products that had been in the field for over ten years.

Character LCD displays are built in standard sizes and configurations. This makes the process of locating an equivalent LCD a simple process, but it is critical to make sure that the replacement display is a drop -in equivalent to your current display. It may not be possible to build a 100% equivalent product without some modifications.

We are able to match and replace these discontinued Liquid Crystal Displays. There may be a one-time NRE (Non-Recurring Engineering) fee required to modify the ITO glass, PCB (Printed Circuit Board) and bezel to match the dimensions and characteristics necessary for your production.

If your current LCD supplier has discontinued your display, Focus Display Solutions (aka Focus LCDs) has the ability to cross it over to an equivalent display and in many cases Fed Ex/UPS a sample to you the same day.

Note: when you begin ordering LCD displays from Focus, we will supply you with the data sheet. If you purchase the display, you should own the data sheet.

Providing us the full part number of the LCD allows us to determine not only the size of the display, but also the type of construction such as COB (Chip on Board) or COG (Chip on Glass), number of characters, backlight option, operating temperature range, background and backlight colors, viewing angle, backlight and LCD logic voltage, and in most cases the controller driver used.

With the part number, we will attempt to locate a full data sheet with enough details allowing us to quote a replacement for your discontinued display. If we cannot locate a data sheet, we will ask if your previous supplier had provided one to you.

If we are unable to locate the data sheet of your current LCD, we will request a data sheet. If possible, please forward over the data sheet or a link to the data sheet. If your LCD supplier is no longer in business or they will not provide you the data sheet, the next option is a photo of the display.

If you decided to move forward with us and order samples of your replacement display based on the estimated cost, we will require two of your discontinued samples. They do not need to be working displays, but need to be in good condition. Please note: We will not be able to return the two displays.

Note: when you begin ordering LCD displays from Focus, we will supply you with the data sheet. If you purchase the display, you should own the data sheet.

We have an LCD module build on our experimentors board that allows our microcontroller to communicate to us using alpha-numeric text. To use the built-in LCD, we need to add a few lines of additional code.

The first line ANSEL = %01100000 sets the pins (or I/O lines) RA0 to RA4 to digital I/O lines. These lines are dedicated to making the LCD function and are not accessible to us for other uses.

The next line Pause 1000, stops the program execution for one second. This is to allow the LCD to complete its own power up initiation and be available for use.

The next line LCDOUT 254,1, "LED is Blinking", clears the LCD screen, positions the cursor on line 1 position 1 then prints the text "LED is blinking" on the LCD. The LCDOUT command structure is discussed below.

The LCD Module has two operational modes: text and instruction. Both text and commands are access using the same PBP command "LCDOUT". Text and commands may be combined on the same LCDOUT program line, as is the case with our LCDOUT command. ASCII text are called strings. To print the string “Images” use the Command (LCDOUT “Images”) and the text "Images" will appear on the LCD. The string text to be printed is surrounded by double quotation marks "". These double quotation marks are not printed on the LCD.

To input instructions to the LCD module, you must prefix the instruction with ASCII 254 ($FE). The byte following prefix is seen and treated as a instruction code. Every instruction code must be sent with its own 254 prefix. The clear-screen instruction is ASCII 1.

You can also use the hex numbers to send commands. The hex equivalent to decimal number 254 is $FE. So to clear the screen you can also use the command LCDOUT $FE,1.

The LCD displays the first 16 characters on each line. However, each LCD line can hold 40 characters. When you print past the 16 visible characters, the next 24 characters are in an off-screen memory area. This LCD module has 80 bytes of character memory, arranged appropriately for a 2x40 screen. While the off-screen text can’t be seen on the screen, one could use scroll instructions to scroll and reveal the off screen character text.

Your LCD has a back light that is turned on or off using the back light switch. A potentiometer on the back of the board adjusts contrast of the LCD. You can adjust the contrast control by hand or your optimum viewing.

Before moving on to Binary numbers, lets take a quick look at timing. The PIC microcontroller is accurate in regard to timing. If you built the LED blinker you may have noticed that the LED is turning on-off faster than the program cycle calls for. The program cycle states the LED should turn on for 1/2 second then off 1/2 second where the process repeats. While we set the internal oscillator speed to 8 MHz the PBP compiler does not know the oscillator speed we have set. We have to tell it. While our LED blinking program is a trival timing issue, other processes like serial communication require precise timing to be reliable. We can tell the PBP compiler the speed of the oscillator by adding one line to our program.

Liquid crystal display (LCD) is a flat panel display that uses the light modulating properties of liquid crystals. Liquid crystals do not produce light directly, instead using a backlight or reflector to produce images in colour or monochrome.

A lot of LCD displays also allow you to "upload" your own characters, a few of the characters can be overwritten with your own after initialization by writing a series of bits to a memory location on the lcd display. The datasheet should have all the information

Here"s a typical LCD display with chip that"s clone of those HD447800: http://uk.farnell.com/midas/mc42004a6w-bnmlw/lcd-4x20-neg-stn-white-led-b-l/dp/2063162

A fourteen-segment display (FSD) (sometimes referred to as a starburst display or Union Jack displayseven-segment display, having an additional four diagonal and two vertical segments with the middle horizontal segment broken in half. A seven-segment display suffices for numerals and certain letters, but unambiguously rendering the ISO basic Latin alphabet requires more detail.sixteen-segment display which allows additional legibility in displaying letters or other symbols.

Electronic alphanumeric displays may use LEDs, LCDs, or vacuum fluorescent display devices. The LED variant is typically manufactured in single or dual character packages, allowing the system designer to choose the number of characters suiting the application.

A 14-segment display is mostly used to display text because the 14 elements allow all Latin letters to be displayed both in upper case and lower case (with a few exceptions like "s").

Multiple-segment display devices use fewer elements than a full dot-matrix display, and may produce a better character appearance where the segments are shaped appropriately. This can reduce power consumption and the number of driver components.

Fourteen-segment gas-plasma displays were used in pinball machines from 1986 through 1991 with an additional comma and period part making for a total of 16 segments.

Fourteen and sixteen-segment displays were used to produce alphanumeric characters on calculators and other embedded systems. Applications today include displays fitted to telephone Caller ID units, gymnasium equipment, VCRs, car stereos, microwave ovens, slot machines, and DVD players.

Such displays were very common on pinball machines for displaying the score and other information, before the widespread use of dot-matrix display panels.

Multiple segment alphanumeric displays are nearly as old as the use of electricity. A 1908 textbook commutator assembly could be arranged so that as the drum was rotated, different sets of switches were closed and different letters and figures could be displayed. The scheme would have been used for "talking" signs to spell out messages, but a complete set of commutator switches, drums and lamps would have been required for each letter of a message, making the resulting sign quite expensive.

A few different versions of the fourteen segment display exist as cold-cathode neon lamps. For example, one type made by Burroughs Corporation was called "Panaplex". Instead of using a filament as the incandescent versions do, these use a cathode charged to a 180 V potential which causes the electrified segment to glow a bright orange color.Nixie tubes but instead of the full-formed numeric shapes, used segments to make up numerals and letters.

http://www.ineedcaffeine.com/content/the-burroughs-b7971/ Archived 2015-04-02 at the Wayback Machine Burroughs B7971 segmented display tube illustration, retrieved 2012 July 19

Midas Character COG LCD Displays. The chip-on-glass (COG) LCD displays, from Midas Displays, are available in 16, 20 and 24 character options. Technologies include super twisted nematic (STN) or film compensated super twisted nematic (FSTN). Alternative appearances are created with positive and negative modes available in the COB LCD displays. The COG LCD displays have an I2C interface and built in controller and include standard on board character sets. The COB LCD displays are available with a viewing angle of 6 o"clock.. I2C interface Operating temperature -20 to +70 °C STN and FSTN display options