tft display glitch quotation

I am blocked because I have the same TFT as on the photo. I have to connect it to a pcb that use the same SPI for the display and for the touchscreen. I am using a ESP32 but I am not sure it is meaningful.

When the TFT_RST pin is defined as output and set to HIGH, the XPT2046 returns only a value equal to zero when I read it. Otherwise, it replies with values that seems OK (they change when I touch the screen).

Note: I have a friend that has the same TFT. He did not remove the diode (was not aware off this) and his TFT works just fine using exactly the same firmware and the same board.

Hi, i am using 1.8 TFT 128*160 LCD with spi communication. I am using esp32 microcontroller and trying to upload the image to the LCD but i am facing issues with the TFT library.

1. The base system is linux with Matrix_guiE demo running on top. It is based upon the TI 5.02 Linux SDK for AM1808. The linux kernel is modified to support the custom hardware including LCD display and RAM.

It"s called "Remanence effect". Basically the games sections which stay static were displayed at the same place for too long and got "stuck" on that place in your screen. This is a common issue with liquid crystal displays. That"s why on TVs like Samsung, the on screen display (OSD) keeps moving and does not stay static. It only happens if the image stays for very long.

To confirm, I had the T4 intermittently working on both the adafruit ili9341 library and the optimised ili9341_t3. I"ve been through 3 T4s and I have 5 different ILI934 displays. (all give the same results, pull ups, no pullups, removed sd circuitry, ran the T4 at 5v I"ve tried it all!)

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.

PLS (Plane to Line Switching)= S-PLS, a Samsung technology exclusive to them and very similar to LG.Display’s IPS in performance and can therefore be called an “IPS-type” technology

AHVA (Advanced Hyper-Viewing Angle) = developed by AU Optronics as another alternative to LG.Display’s IPS, very similar again and so can be called “IPS-type”

Colour gamut – don’t assume that a higher colour gamut is better! The gamut represents the colour space that the backlighting unit of the monitor allows the screen to display. You need to understand that most normal content is based on a certain colour space (sRGB) and that there can be issues if you view this using a wide gamut screen. See here for more information.

A. Generally nowadays with all the ultra-low response time models available, ghosting caused by slow pixel response times is just not an issue for the majority of users. Performance has improved significantly over the years and blurring and ghosting has been largely eliminated on the faster displays. The use of RTC technologies (overdrive) significantly helps improve response times and speed up pixel transitions. This is particularly important on IPS/VA type displays which can be very slow where RTC is not used. Look out for response time specs quoted with a “G2G” (grey to grey) response time as that should indicate the use of overdrive technologies.

Nowadays screens supporting high refresh rates (120Hz+) input frequencies are becoming more and come common, and these can help reduce motion blur and ghosting and improve gaming performance considerably. They are also able to support higher frame rates than traditional 60Hz displays and some are also capable of supporting 3D stereoscopic content through active shutter glasses. Do be careful of assuming that a screen advertised as supporting 3D is in fact able to support 120Hz though, as some 3D models do not support this and instead use passive methods to produce the 3D effect (see here for more info on 3D technologies). Refresh rate of the panel does have a direct impact on motion clarity and for optimal gaming performance you will want to consider those high refresh rate displays above 60Hz.

Ghosting and motion blur perception may also depend on how susceptible you are as a user, as one person may see no ghosting, another may see lots on the same panel. The best bet is to try and see a TFT in action in a shop and see for yourself, if that’s not possible you will have to settle for the opinions of other users and take the plunge! Also be careful to get an idea of real life performance in practice, and don’t just rely on quoted specs. While they are often a good rough guide to the gaming performance, they are not always reliable.

One area which cannot be eliminated fully through response time improvements is perceived motion blur. This is related to how the human eye tracks movement on hold-type displays like LCD’s. In recent years several methods have been used to help provide improved motion blur for users. Models featuring LightBoost backlights for 3D gaming were found to be “hackable” to bring about motion blur benefits through the use of their strobed backlight system. Other displays have now introduced native strobed backlights to offer similar benefits. Look out for models with Motion Blur Reduction backlights like the BenQ XL2420Z / XL2720Z (Blur Reduction mode), Eizo Foris FG2421 (Turbo 240) and Asus ROG Swift PG278Q (ULMB) for instance. ULMB as a feature is common on NVIDIA G-sync enabled displays where high refresh rate is used.

A. As a rule of thumb, it would normally be best to use the digital video connection end to end to connect your device to your monitor. For a PC, this would commonly be DisplayPort, HDMI or DVI which offer a pure digital end to end connection between the graphics card and the monitor. DisplayPort is needed to run the high resolution/high refresh rate panels so you will need to ensure your graphics card has a DP output. Some screens or cards use Mini DP instead of the full size version, but that is simply a different size connection and can be easily inter-changed with “normal” DisplayPort. Cables which are DP at one end, and Mini DP at the other are common and simple to use.

HDMI and DisplayPort are also common digital connections now being offer, but unlike DVI are also capable of carrying audio as well as video. The picture quality should not be any different between DVI, HDMI and DisplayPort in theory as long as no additional video “enhancements” are applied when using one over the other. Bandwidth requirements will vary so this might influence which type you need to use depending on the screen resolution and refresh rate.

Converting between DVI and HDMI is easy and cables are readily available to offer that if needed (keeping in mind you will lose the sound transmission when it reaches the DVI). Converting between DVI/HDMI and DisplayPort is far more tricky and not simple to achieve. It is very hit and miss and working active adapters are expensive. We would advise avoiding the attempt to convert DP to HDMI/DVI if you can.

A. There is a lot of talk about colour depth on TFT screens, now more than ever with the emergence of 6-bit IPS and VA panels. At one time TN Film was the main 6-bit technology but today that is no longer the case. It’s important to put this into perspective though, and not jump on the bandwagon of 8-bit being much, much better than 6-bit. Or even 10-bit being much better than 8-bit.

An 8-bit display would offer a colour palette of 16.7 million colours. They offer a ‘true’ colour palette, and are generally the choice of manufacturers for colour critical displays over 6-bit panels. On the other hand modern 6-bit screens use a range of Frame Rate Control (FRC) technologies to extend the colour palette from 262,144 colours to around 16.7m. In fact on many modern panels these FRC are very good and in practice you’d be hard pressed to spot any real difference between a 6-bit + FRC display and a true 8-bit display. Colour range is good, screens show no obvious gradation of colours, and they show no FRC artefacts or glitches in normal everyday use. Most average users would never notice the difference and so it is more important to think about the panel technology and your individual uses than get bogged down worrying about 6-bit vs. 8-bit arguments.

Manufacturers use 6-bit panels (+FRC) to help keep costs lower. As a result, a modern range of IPS and VA panels is also now produced which use 6-bit colour depth (+FRC) instead of true 8-bit colour depths. At the other end of the scale there are also some panels which can offer support of 10-bit colour depth. Again these come in two flavours, being either a true 10-bit panel (quite rare and expensive) offering 1.07 billion colours or an 8-bit panel with an additional FRC stage added (1.07 billion colours produced through FRC). The 8-bit +FRC panels are of course more common and will often be used to offer “10-bit” support in desktop displays. With 10-bit colour though there is also an additional consideration which is whether you would ever even be able to use this in your work. You can also only make use of this 10-bit support if you have a full end-to-end 10-bit workflow, including a supporting software, graphics card and operating system which is still very rare and expensive for most users. So for many people the use of a 10-bit capable panel is rather meaningless.

While a larger colour space might sound like a good idea, it’s not always for everyone. You need to keep in mind what content you will be viewing on the screen, and what colour space that content is based on. Since sRGB is very common and the standard for many things like Windows and the internet, viewing sRGB content on an extended gamut screen can cause oversaturation of colours and an unrealistic ‘stretching’ of the colours. Reds and greens in particular can appear quite ‘neon’ and some users do not like this. The smaller colour space of the content is, as a very crude description, ‘stretched’ over the larger colour space of the monitor. On the other hand, some applications are colour space aware (e.g. Adobe Photoshop) and so if you are working with extended gamut content, you will prefer an extended gamut screen. I’d certainly recommend reading more into this as it is only a brief summary here. Where a screen has an extended gamut, they sometimes provide an sRGB emulation mode which work to varying degrees. Handy if you might need to use it, but make sure the screen offers a decent performance when in this mode and that it works. At the end of the day, the choice of monitor might very well depend on the colour space you want to work with. For most average users a standard CCFL or W-LED backlit display with a standard sRGB gamut would probably be preferred.

A. The simplest and cheapest way to clean a TFT screen is with a slightly damp cloth; wipe off the left behind water with a towel or similar then smooth/dry completely with a yellow polishing cloth. Be careful not to use products such as toilet paper and kitchen roll as they contain lint and can leave scratches on your beloved screen! Cleaning solution from opticians and lint free clothes for lens cleaning are also very good.

A. Unfortunately dead pixels can be an issue on TFT screens as they are often developed during the manufacturing stage. For retail costs to be kept low the companies cannot afford to make all screens defect-free and check for dead pixels all the time. Pixels can be described in the following ways:

If you want to ensure that you receive a pixel perfect screen (and who wouldn’t at the kind of prices you are paying for the TFT!?!) then you can often pay for pixel checks from some online retailers. Beware though! Never buy a TFT from retailers who offer the pixel check without having the check done as you can be sure the screens they find to be non-perfect will be winging their way to the customers who don’t have the check! The only other option to ensure you get a pixel perfect screen is to check out the panel in a shop in person, then you can see for yourself…..

If you find you have a dead pixel there is not a lot you can do unfortunately. If you have a certain number of dead pixels (usually at least 3 or a certain number centrally on the panel) then the manufacturer will replace the TFT for you, but the number of dead pixels needed before this happens varies between each manufacturer, so check with them before you order if you’re concerned.

If you still have a dead pixel problem, can’t bring it back to life and can’t RMA it under warranty then you can sometimes return it to the stockist if you purchased it online. If you bought online you can take advantage of the “Distance Selling Act” which entitles you to return any item within 7 days as you were not present at the time of purchase. If you are not happy with your TFT you can return it at your cost of postage and often claim a refund or exchange. However, be aware that a lot of places will try and charge you restocking fees and they will almost certainly specify the goods must be packaged and in the same condition as when you received it, so be careful to package it back up nicely. Legally, if the stocker accepts the TFT back as a return governed by the Distance Selling Act, then they are NOT allowed to charge you a restocking fee as covered in the Government Regulations. This selling act is not widely advertised by retailers, but does exist if you really need to use it. You should only have to pay for postage to send it back to them.