arduino mega tft lcd projects made in china

I bought a cheap LCD screen for a project I"m working on to get my feet wet with programming LCD touch screens before buying a "full-size" screen. But i can not find any libraries or code to get it to display anything. Ive downloaded the new ILI9341 library along with 4-5 other ones and can not get it to display or do anything.

Im using an UNO with THIS display. i would prefer to use my mega but this one says it is only for the UNO. I tried the links on the eBay page for getting it to work but they didn"t seem to help.

In this Arduino touch screen tutorial we will learn how to use TFT LCD Touch Screen with Arduino. You can watch the following video or read the written tutorial below.

As an example I am using a 3.2” TFT Touch Screen in a combination with a TFT LCD Arduino Mega Shield. We need a shield because the TFT Touch screen works at 3.3V and the Arduino Mega outputs are 5 V. For the first example I have the HC-SR04 ultrasonic sensor, then for the second example an RGB LED with three resistors and a push button for the game example. Also I had to make a custom made pin header like this, by soldering pin headers and bend on of them so I could insert them in between the Arduino Board and the TFT Shield.

Here’s the circuit schematic. We will use the GND pin, the digital pins from 8 to 13, as well as the pin number 14. As the 5V pins are already used by the TFT Screen I will use the pin number 13 as VCC, by setting it right away high in the setup section of code.

I will use the UTFT and URTouch libraries made by Henning Karlsen. Here I would like to say thanks to him for the incredible work he has done. The libraries enable really easy use of the TFT Screens, and they work with many different TFT screens sizes, shields and controllers. You can download these libraries from his website, RinkyDinkElectronics.com and also find a lot of demo examples and detailed documentation of how to use them.

After we include the libraries we need to create UTFT and URTouch objects. The parameters of these objects depends on the model of the TFT Screen and Shield and these details can be also found in the documentation of the libraries.

So now I will explain how we can make the home screen of the program. With the setBackColor() function we need to set the background color of the text, black one in our case. Then we need to set the color to white, set the big font and using the print() function, we will print the string “Arduino TFT Tutorial” at the center of the screen and 10 pixels  down the Y – Axis of the screen. Next we will set the color to red and draw the red line below the text. After that we need to set the color back to white, and print the two other strings, “by HowToMechatronics.com” using the small font and “Select Example” using the big font.

In order the code to work and compile you will have to include an addition “.c” file in the same directory with the Arduino sketch. This file is for the third game example and it’s a bitmap of the bird. For more details how this part of the code work  you can check my particular tutorial. Here you can download that file:

No! For about the price of a familiar 2x16 LCD, you get a high resolution TFT display. For as low as $4 (shipping included!), it"s possible to buy a small, sharp TFT screen that can be interfaced with an Arduino. Moreover, it can display not just text, but elaborate graphics. These have been manufactured in the tens of millions for cell phones and other gadgets and devices, and that is the reason they are so cheap now. This makes it feasible to reuse them to give our electronic projects colorful graphic displays.

There are quite a number of small cheap TFT displays available on eBay and elsewhere. But, how is it possible to determine which ones will work with an Arduino? And what then? Here is the procedure:ID the display. With luck, it will have identifying information printed on it. Otherwise, it may involve matching its appearance with a picture on Google images. Determine the display"s resolution and the driver chip.

Find out whether there is an Arduino driver available. Google is your friend here. Henning Karlsen"s UTFT library works with many displays. (http://www.rinkydinkelectronics.com/library.php?i...)

Download and install the driver library. On a Linux machine, as root, copy the library archive file to the /usr/share/arduino/libraries directory and untar or unzip it.

Load an example sketch into the Arduino IDE, and then upload it to the attached Arduino board with wired-up TFT display. With luck, you will see text and/or graphics.

We"ll begin with a simple one. The ILI9163 display has a resolution of 128 x 128 pixels. With 8 pins in a single row, it works fine with a standard Arduino UNO or with a Mega. The hardware hookup is simple -- only 8 connections total! The library put together by a smart fella, by the name of sumotoy, makes it possible to display text in multiple colors and to draw lines.

Note that these come in two varieties, red and black. The red ones may need a bit of tweaking to format the display correctly -- see the comments in the README.md file. The TFT_ILI9163C.h file might need to be edited.

It is 5-volt friendly, since there is a 74HC450 IC on the circuit board that functions as a level shifter. These can be obtained for just a few bucks on eBay and elsewhere, for example -- $3.56 delivered from China. It uses Henning Karlsen"s UTFT library, and it does a fine job with text and graphics. Note that due to the memory requirement of UTFT, this display will work with a standard UNO only with extensive tweaking -- it would be necessary to delete pretty much all the graphics in the sketch, and just stay with text.

on the far side of the display. It has 220x176 resolution (hires!) and will accept either 3.3 or 5 volts. It will work hooked up to an Uno, and with a few pin changes, also with a Mega. The 11-pin row is for activating the display itself, and the 5-pin row for the SD socket on its back.

This one is a 2.2" (diagonal) display with 176x220 resolution and parallel interface. It has a standard ("Intel 8080") parallel interface, and works in both 8-bit and 16-bit modes. It uses the S6D0164 driver in Henning Karlsen"s UTFT library, and because of the memory requirements of same, works only with an Arduino Mega or Due. It has an SD card slot on its back

This one is a bit of an oddball. It"s a clone of the more common HY-TFT240, and it has two rows of pins, set at right angles to one another. To enable the display in 8-bit mode, only the row of pins along the narrow edge is used. The other row is for the SD card socket on the back, and for 16-bit mode. To interface with an Arduino ( Mega or Due), it uses Henning Karlsen"s UTFT library, and the driver is ILI9325C. Its resolution is 320x240 (hires!) and it incorporates both a touch screen and an SD card slot.

Having determined that a particular TFT display will work with the Arduino, it"s time to think about a more permanent solution -- constructing hard-wired and soldered plug-in boards. To make things easier, start with a blank protoshield as a base, and add sockets for the TFT displays to plug into. Each socket row will have a corresponding row next to it, with each individual hole "twinned" to the adjacent hole in the adjoining row by solder bridges, making them accessible to jumpers to connect to appropriate Arduino pins. An alternative is hard-wiring the socket pins to the Arduino pins, which is neater but limits the versatility of the board.

In step 5, you mention that the TFT01 display can"t be used with the UTFT library on an Arduino Uno because of its memory requirements. It can - all you have to do is edit memorysaver.h and disable any display models you"re not using.

I think you should add a disclaimer that the code might make the Arduino Uno unprogrammable afterward (due to use up the two 0 and 1 pin) and link to how to fix it: https://stackoverflow.com/questions/5290428/how-to-reset-an-arduino-board/8453576?sfb=2#84535760

Tho I realize this is quickly becoming legacy hardware, these 8,16 bit parallel spi with 4 wire controller 3.2in Taft touch display 240x380. It has become very inexpensive with ally of back stock world wide so incorporating them into any project is easier then ever. Sorry to my question. I’m having difficulty finding wiring solution for this lcd. It is a sd1289 3.3 and 5v ,40 pin parallel 8,16 bit. I do not want to use a extra shield,hat or cape or adapter. But there’s a lot of conflicting info about required lvl shifters for this model any help or links to info would be great .. thank you. I hope I gave enough information to understand what I’m adoing

#1 you need a data sheet for the display and pinout and the i/o board attached to the cable.Than before you buy check for a driver for this chip Raydium/RM69071.if no driver lib are you able to write one and do you have the necessary tools to work on this scale to wire it up ..if you answer no than search for an arduino ready product.WCH0

hooking up and adding a lib is no piece of cake insure the screen you buy is arduino ready and sold by a reputable shop with step by step directions...WCH0

I"m sorry that I can"t help you with this. You"ll have to do your own research. See if you can identify the chipset and find out if there"s an Arduino driver for it.0

To make my projects with Arduino even more interesting bought this display of 3.5 inches. I thought I had bought a version with touch screen, but then I discovered that the version with support for touch screen sells in this other link.

It is a shield, IE, is to be plugged directly into the Arduino. My complaint is that does not extend any PIN and practically uses all, IE, You can"t do much on the Arduino UNO but play with the display. Detail to support the SD card to upload images.

Look at the game with different fonts and colors. To make something appear you must install some. I installed from this link, the version 1.1. The libraries are the Adafruit_GFX and Adafruit_TFTLCD. The touchscreen version also needs a library that can be downloaded on the same link, switching to the version 2.0.

Take a look at the video I made showing a program that generates circles, rectangles and triangles with random colors, In addition to the display pattern that comes with the library. I used the Arduino UNO:

I found the display quite slow. Not to make a watch, for example, because the display is blinking a lot when updated second by second. Maybe we can make a graph of the analog input A5, that doesn"t appear to be used to control, but to do so would have to weld or fit any wires directly into the board, because this shield does not extend any of the pins. Who knows in the Arduino Mega works best? I leave below link to the version with touchscreen and without touchscreen:

Arduino has always helped to build projects easily and make them look more attractive.  Programming an LCD screen with touch screen option might sound as a complicated task, but the Arduino libraries and shields had made it really easy. In this project we will use a 2.4” Arduino TFT LCD screen to build our own Arduino Touch Screen calculator that could perform all basic calculations like Addition, Subtraction, Division and Multiplication.

Before we actually dive into the project it is important to know, how this 2.4” TFT LCD Module works and what are the types present in it. Let us take a look at the pinouts of this 2.4” TFT LCD screen module.

As you can see there are 28 pins which will perfectly fit into any Arduino Uno / Arduino Mega Board. A small classification of these pins is given in the table below.

As you can see the pins can be classified in to four main classifications such as LCD Command Pins, LCD Data Pins, SD Card Pins and Power Pins, We need not know much about the detailed working of these pins since they will be take care by our Arduino Library.

You can also find an SD card slot at the bottom of the module shown above, which can be used to load an SD card with bmp image files, and these images can be displayed in our TFT LCD screen using the Arduino Program.

Another important thing to note is your Interface IC. There are many types of TFT modules available in the market starting from the original Adafruit TFT LCD module to cheap Chinese clones. A program which works perfectly for your Adafruit shield might not work the same for Chinese breakout boards. So, it is very important to know which types of LCD display your are holding in hand. This detail has to be obtained from the vendor. If you are having a cheap clone like mine then it is most probably using the ili9341 driver IC.You can follow this TFT LCD interfacing with Arduino tutorial to try out some basic example programs and get comfortable with the LCD screen. Also check out our other TFT LCD projects with Arduino here:

If you planning to use the touch screen function of your TFT LCD module, then you have to calibrate it to make it work properly.  A LCD screen without calibration might work unlikely, for instance you might touch at one place and the TFT might respond for a touch at some other place. These calibrations results will not be similar for all boards and hence you are left on your own to do this.

The 2.4” TFT LCD screen is a perfect Arduino Shield. You can directly push the LCD screen on top of the Arduino Uno and it will perfectly match with the pins and slid in through. However, as matters of safety cover the Programming terminal of your Arduino UNO with a small insulation tape, just in case if the terminal comes in contact with your TFT LCD screen. The LCD assembled on UNO will look something like this below.

We are using the SPFD5408 Library to get this arduino calculator code working. This is a modified library of Adafruit and can work seamlessly with our LCD TFT Module. You can check the complete program at the end of this Article.

Now, open Arduino IDE and select Sketch -> Include Librarey -> Add .ZIP library. A browser window will open navigate to the ZIP file and click “OK”. You should notice “Library added to your Libraries” on the bottom-left corner of Arduino, if successful. A detailed guide to do the same is given in the Interfacing Tutorial.

Now, you can use the code below in your Arduino IDE and upload it to your Arduino UNO for the Touch Screen Calculator to work. Further down, I have explained the code into small segments.

As said earlier we need to calibrate the LCD screen to make it work as expected, but don’t worry the values given here are almost universal. The variables TS_MINX, TS_MINY, TS_MAXX, and TS_MAXY decide the calibration of the Screen. You can toy around them if you feel the calibration is not satisfactory.

As we know the TFT LCD screen can display a lot of colours, all these colours have to be entered in hex value. To make it more human readable we assign these values to a variable as shown below.

The final step is to calculate the result and display them on TFT LCD Screen. This arduino calculator can perform operation with 2 numbers only. These two numbers are named as variables “Num1” and “Num2”. The variable “Number” gives and takes value from Num1 and Num2 and also bears the result.

The working of this Arduino Touch Screen Calculator is simple. You have to upload the below given code on your Arduino and fire it up. You get the calculator displayed on your LCD screen.

The ST7789 TFT module contains a display controller with the same name: ST7789. It’s a color display that uses SPI interface protocol and requires 3, 4 or 5 control pins, it’s low cost and easy to use. This display is an IPS display, it comes in different sizes (1.3″, 1.54″ …) but all of them should have the same resolution of 240×240 pixel, this means it has 57600 pixels. This module works with 3.3V only and it doesn’t support 5V (not 5V tolerant).

As mentioned above, the ST7789 TFT display controller works with 3.3V only (power supply and control lines). The display module is supplied with 3.3V (between VCC and GND) which comes from the Arduino board.

To connect the Arduino to the display module, I used voltage divider for each line which means there are 4 voltage dividers. Each voltage divider consists of 2.2k and 3.3k resistors, this drops the 5V into 3V which is sufficient.

The first library is a driver for the ST7789 TFT display which can be installed from Arduino IDE library manager (Sketch —> Include Library —> Manage Libraries …, in the search box write “st7789” and install the one from Adafruit).

Checking a TFT lcd driver is very messy thing especially if its a Chinese manufactured TFT. TFT’s that are supplied by Chinese manufactures are cheap and every body loves to purchase them since they are cheap,but people are unaware of the problems that comes in future when finding the datasheet or specs of the particular TFT they purchased. Chinese manufactures did not supply datasheet of TFT or its driver. The only thing they do is writes about the TFT driver their lcd’s are using on their websites. I also get in trouble when i started with TFT’s because i also purchased a cheap one from aliexpress.com. After so many trials i succeeded in identifying the driver and initializing it. Now i though to write a routine that can identify the driver.

I wrote a simple Arduino Sketch that can easily and correctly identify the TFT Lcd driver. I checked it on 2.4, 3.2 and 3.8 inch 8-bit TFT lcd and it is identifying the drivers correctly. The drivers which i successfully recognized are ILI9325, ILI9328, ILI9341, ILI9335, ST7783, ST7781 and ST7787. It can also recognize other drivers such as ML9863A, ML9480 and ML9445 but i don’t have tft’s that are using this drivers.

The basic idea behind reading the driver is reading the device ID. Since all the drivers have their ID’s present in their register no 0x00, so what i do is read this register and identify which driver tft is using. Reading the register is also a complex task, but i have gone through it many times and i am well aware of how to read register. A simple timing diagram from ST7781 driver explains all. I am using tft in 8-bit interface so i uploaded timing diagram of 8-bit parallel interface. The diagram below is taken from datasheet of ST7781 tft lcd driver.

The most complex tft i came across is from a Chinese manufacturer “mcufriend”. mcufriend website says that they use ILI9341 and ILI9325 drivers for their tft’s. But what i found is strange their tft’s are using ST7781 driver(Device ID=7783). This is really a mesh. I have their 2.4 inch tft which according to their website is using ILI9341 driver but i found ST7783 driver(Device ID=7783). The tft i have is shown below.

I am using Arduino uno to read driver. I inserted my lcd on arduino uno and read the driver. After reading driver i am printing its number on Serial Monitor.

Note:On serial monitor driver number will be displayed like if your lcd is using ST7783 controller than on serial monitor 7783 will be displayed or if tft is using ILI9341 than on 9341 will be displayed.

The code works on Arduino uno perfectly but if you are using any other board, than just change the pin numbers according to the board that you are using also check out for the Ports D and B. TFT Data Pin D0 is connected to Port-B Pin#0 and D1 is connected to Port-B Pin#1. TFT Data Pins D2 to D7 are connected to Port-D Pins 2,3,4,5,6,7. So if you are using Arduino mega than check for the Ports D and B and Make connections according to them. Arduino mega is working on ATmega2560 or ATmega1280 Microcontroller and Arduino uno is working on ATmega328p Microcontroller so both platforms have ports on different locations on arduino board so first check them and then make connections. The same process applies to all Arduino boards.

In this article, you will learn how to use TFT LCDs by Arduino boards. From basic commands to professional designs and technics are all explained here.

In electronic’s projects, creating an interface between user and system is very important. This interface could be created by displaying useful data, a menu, and ease of access. A beautiful design is also very important.

There are several components to achieve this. LEDs,  7-segments, Character and Graphic displays, and full-color TFT LCDs. The right component for your projects depends on the amount of data to be displayed, type of user interaction, and processor capacity.

TFT LCD is a variant of a liquid-crystal display (LCD) that uses thin-film-transistor (TFT) technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.

In Arduino-based projects, the processor frequency is low. So it is not possible to display complex, high definition images and high-speed motions. Therefore, full-color TFT LCDs can only be used to display simple data and commands.

In electronic’s projects, creating an interface between user and system is very important. This interface could be created by displaying useful data, a menu, and ease of access. A beautiful design is also very important.

There are several components to achieve this. LEDs,  7-segments, Character and Graphic displays, and full-color TFT LCDs. The right component for your projects depends on the amount of data to be displayed, type of user interaction, and processor capacity.

TFT LCD is a variant of a liquid-crystal display (LCD) that uses thin-film-transistor (TFT) technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.

In Arduino-based projects, the processor frequency is low. So it is not possible to display complex, high definition images and high-speed motions. Therefore, full-color TFT LCDs can only be used to display simple data and commands.

After choosing the right display, It’s time to choose the right controller. If you want to display characters, tests, numbers and static images and the speed of display is not important, the Atmega328 Arduino boards (such as Arduino UNO) are a proper choice. If the size of your code is big, The UNO board may not be enough. You can use Arduino Mega2560 instead. And if you want to show high resolution images and motions with high speed, you should use the ARM core Arduino boards such as Arduino DUE.

In electronics/computer hardware a display driver is usually a semiconductor integrated circuit (but may alternatively comprise a state machine made of discrete logic and other components) which provides an interface function between a microprocessor, microcontroller, ASIC or general-purpose peripheral interface and a particular type of display device, e.g. LCD, LED, OLED, ePaper, CRT, Vacuum fluorescent or Nixie.

The LCDs manufacturers use different drivers in their products. Some of them are more popular and some of them are very unknown. To run your display easily, you should use Arduino LCDs libraries and add them to your code. Otherwise running the display may be very difficult. There are many free libraries you can find on the internet but the important point about the libraries is their compatibility with the LCD’s driver. The driver of your LCD must be known by your library. In this article, we use the Adafruit GFX library and MCUFRIEND KBV library and example codes. You can download them from the following links.

You must add the library and then upload the code. If it is the first time you run an Arduino board, don’t worry. Just follow these steps:Go to www.arduino.cc/en/Main/Software and download the software of your OS. Install the IDE software as instructed.

First you should convert your image to hex code. Download the software from the following link. if you don’t want to change the settings of the software, you must invert the color of the image and make the image horizontally mirrored and rotate it 90 degrees counterclockwise. Now add it to the software and convert it. Open the exported file and copy the hex code to Arduino IDE. x and y are locations of the image. sx and sy are sizes of image. you can change the color of the image in the last input.

Upload your image and download the converted file that the UTFT libraries can process. Now copy the hex code to Arduino IDE. x and y are locations of the image. sx and sy are size of the image.

In this template, We converted a .jpg image to .c file and added to the code, wrote a string and used the fade code to display. Then we used scroll code to move the screen left. Download the .h file and add it to the folder of the Arduino sketch.

In this template, We used sin(); and cos(); functions to draw Arcs with our desired thickness and displayed number by text printing function. Then we converted an image to hex code and added them to the code and displayed the image by bitmap function. Then we used draw lines function to change the style of the image. Download the .h file and add it to the folder of the Arduino sketch.

In this template, We added a converted image to code and then used two black and white arcs to create the pointer of volumes.  Download the .h file and add it to the folder of the Arduino sketch.

In this template, We added a converted image and use the arc and print function to create this gauge.  Download the .h file and add it to folder of the Arduino sketch.

while (a < b) { Serial.println(a); j = 80 * (sin(PI * a / 2000)); i = 80 * (cos(PI * a / 2000)); j2 = 50 * (sin(PI * a / 2000)); i2 = 50 * (cos(PI * a / 2000)); tft.drawLine(i2 + 235, j2 + 169, i + 235, j + 169, tft.color565(0, 255, 255)); tft.fillRect(200, 153, 75, 33, 0x0000); tft.setTextSize(3); tft.setTextColor(0xffff); if ((a/20)>99)

while (b < a) { j = 80 * (sin(PI * a / 2000)); i = 80 * (cos(PI * a / 2000)); j2 = 50 * (sin(PI * a / 2000)); i2 = 50 * (cos(PI * a / 2000)); tft.drawLine(i2 + 235, j2 + 169, i + 235, j + 169, tft.color565(0, 0, 0)); tft.fillRect(200, 153, 75, 33, 0x0000); tft.setTextSize(3); tft.setTextColor(0xffff); if ((a/20)>99)

In this template, We display simple images one after each other very fast by bitmap function. So you can make your animation by this trick.  Download the .h file and add it to folder of the Arduino sketch.

In this template, We just display some images by RGBbitmap and bitmap functions. Just make a code for touchscreen and use this template.  Download the .h file and add it to folder of the Arduino sketch.

After two theory-loaded blog posts about handling data array-like in strings (Strings, arrays, and the less known sp(lit)str(ing) function and Strings & arrays - continued) which you are highly recommended to read before continuing here, if you haven"t already, it"s big time to see how things work in practice! We"ll use a string variable as a lookup lookup table containing data of one single wave period and add this repeatedly to a waveform component until it"s full.A few weeks ago, I wrote this article about using a text variable as an array, either an array of strings or an array of numbers, using the covx conversion function in addition for the latter, to extract single elements with the help of the spstr function. It"s a convenient and almost a "one fits all" solution for most use cases and many of the demo projects or the sample code attached to the Nextion Sunday Blog articles made use of it, sometimes even without mentioning it explicitly since it"s almost self-explaining. Then, I got a message from a reader, writing: "... Why then didn"t you use it for the combined sine / cosine lookup table in the flicker free turbo gauge project?"105 editions of the Nextion Sunday blog in a little over two years - time to look back and forth at the same time. Was all the stuff I wrote about interesting for my readers? Is it possible at all to satisfy everybody - hobbyists, makers, and professionals - at the same time? Are people (re-)using the many many HMI demo projects and code snippets? Is anybody interested in the explanation of all the underlying basics like the algorithms for calculating square roots and trigonometric functions with Nextion"s purely integer based language? Are optimized code snippets which allow to save a few milliseconds here and there helpful to other developers?Looking through the different Nextion user groups on social networks, the Nextion user forum and a few not so official but Nextion related forums can be surprising. Sometimes, Nextion newbies ask questions or have issues although the required function is well (in a condensed manner for the experienced developer, I admit) documented on the Nextion Instruction Set page, accessible through the menu of this website. On top of that, there is for sure one of my more than 100 Sunday blog articles which deals not only with that function, but goes often even beyond the usual usage of it. Apparently, I should sometimes move away from always trying to push the limits and listen to the "back to the roots!" calls by my potential readers...Do you remember the (almost) full screen sized flicker free and ultra rapid gauge we designed in June? And this without using the built-in Gauge component? If not, it"s time to read this article first, to understand today"s improvements. The June 2022 version does its job perfectly, the needle movement is quick and smooth, and other components can be added close to the outer circle without flickering since there is no background which needs constantly to be redrawn. But there was a minor and only esthetic weak point: The needle was a 1px thin line, sometimes difficult to see. Thus, already a short time after publishing, some readers contacted me and asked if there were a way to make the needle thicker, at least 2 pixels.Recently, when playing with a ESP32 based NodeMCU 32S and especially with its WiFi configuration, I did as (I guess) everybody does: I loaded an example sketch to learn more about the Wifi library. When you set up the ESP32 as an access point, creating its own wireless network, everything is pretty straightforward. You can easily hard code the Wifi name (SSID) and the password. But what about the client mode ? Perhaps one needs to use it in different environments. And then, a hard coded network name and password are definitively not the best solution. Thus, I thought, why not use a Nextion HMI for a dynamic WiFi setup functionality?

While I was looking for a TFT display for a project with Arduino, I found on several webstores some displays based on the ST7735 chip by Sitronix (datasheet).

First identify – based on your Arduino board – which pins correspond to the different signals of the SPI bus. For the others, you can freely choose between the remaining pins.

(as you see, I connected the BLK pin directly to Vcc to have the backlight always on. You can also connect it to an Arduino digital pin to be able to control the backlight via software, for example if you need to save power).