3.5 tft lcd code mcufriend pricelist

I bought four MCU Friend 3.5″ TFT shields.  And, unfortunately, they have spiraled me into a deep, dark place trying to figure out how to use them.  The the documentation consists of a sticker on the antistatic bag, a picture of the shield with a list of 5 different possible LCD drivers, a pinout, and a block of code that supposedly represents the startup code.  The unfortunate part is that none of these have been exactly right – they all have errors.  This article is a description of the journey to figuring out how to use them.

Here is a picture of the bag. (the QR code is a number “181024202132” which I thought might be a phone number but isn’t.  It also doesn’t match anything in google, so i’m not sure what it is.

It also has a picture which says the LCD has one of several different controllers (and after digging in I know for a fact that two of mine were made by Raydium and are not on the list)

The first thing I did was try to use the MCUFRIEND_kbv library to see if the screens worked.  The first board identified as ID=0x9403 and did not work.  Apparently, the tool just spits out the ID if it doesn’t know it, which it did not.

One of the boards identified as ID=0x6814 worked perfectly, and one had a blue cast to all of the screens.  The crazy part is the two boards that identified as ID=0x6814 had different PCBs.  According to the comments in the MCUFRIEND_kbv.cpp ID=0x6814 is an RM68140 and ID=9403 is unknown.

Next, I started down the path of trying to figure out what the controllers were by using register reads.  David Prentice (the guy who wrote/maintains the MCU Friend_kbv Arduino library) has an absolute ton of responses on the Arduino forum trying to help people figure out what their shield is.  He asks them to post the register report from his example program LCD_ID_readnew which is included as an example in the library.

When you look at these LCD controllers they all have some variant of “Read ID” which responds with 1-6 bytes.  The basic idea of this program is to look at what bytes are returned to try to identify the controller.  Here is an example of what I got when I ran the LCD_ID_readnew program on my shields:

The key thing to see in this output is the register 0x04 which says 54,80,66 which identifies this as a Raydium RM68140 LCD controller.  Here is a snapshot from the data sheet.

After digging some more, I decided that it is super ugly out there, as you find that there are a significant number of LCD controllers that are clones, copies, pirated etc… and that they all present themselves differently.  And, in hindsight I think that this is the reason that my ILI9341 from the previous article doesnt quite work correctly.

The next thing that I did was try out the startup code that MCUFriend_kbv generates.  I used the same technique from PSoC 6 + Segger EmWin + MCUFriend 2.4″ Part 1 and spit out the startup bytes.  Here they are:

Well, things still aren’t quite right, so for some strange reason, I keep going and try to use the startup code from the web.  In order to make it work I translate

Earlier I told you that I much preferred to use the more compact startup code.  In order to match this, I decided to add a new code “0xDD” which means delay.  (I hope that there are no controllers out there that use 0XDD).  Here is the updated function:

At this point I have spent a frightening amount of time figuring out how these screens work.  Although it has been a good learning experience, I have generally decided that using unknown displays from China with LCD drivers of questionable origin is not worth the pain of trying to sort out the interface.  Beyond that:

Displays are one of the best ways to provide feedback to users of a particular device or project and often the bigger the display, the better. For today’s tutorial, we will look on how to use the relatively big, low cost, ILI9481 based, 3.5″ Color TFT display with Arduino.

This 3.5″ color TFT display as mentioned above, is based on the ILI9481 TFT display driver. The module offers a resolution of 480×320 pixels and comes with an SD card slot through which an SD card loaded with graphics and UI can be attached to the display. The module is also pre-soldered with pins for easy mount (like a shield) on either of the Arduino Mega and Uno, which is nice since there are not many big TFT displays that work with the Arduino Uno.

To easily write code to use this display, we will use the GFX and TFT LCD libraries from “Adafruit” which can be downloaded here. With the library installed we can easily navigate through the examples that come with it and upload them to our setup to see the display in action. By studying these examples, one could easily learn how to use this display. However, I have compiled some of the most important functions for the display of text and graphics into an Arduino sketch for the sake of this tutorial. The complete sketch is attached in a zip file under the download section of this tutorial.

As usual, we will do a quick run through of the code and we start by including the libraries which we will use for the project, in this case, the Adafruit GFX and TFT LCD libraries.

With this done, the Void Setup() function is next. We start the function by issuing atft.reset() command to reset the LCD to default configurations. Next, we specify the type of the LCD we are using via the LCD.begin function and set the rotation of the TFT as desired. We proceed to fill the screen with different colors and display different kind of text using diverse color (via the tft.SetTextColor() function) and font size (via the tft.setTextSize() function).

The Adafruit library helps reduce the amount of work one needs to do while developing the code for this display, leaving the quality of the user interface to the limitations of the creativity and imagination of the person writing the code.

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.

As the code is a bit longer and for better understanding I will post the source code of the program in sections with description for each section. And at the end of this article I will post the complete source 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.

Ok next is the RGB LED Control example. If we press the second button, the drawLedControl() custom function will be called only once for drawing the graphic of that example and the setLedColor() custom function will be repeatedly called. In this function we use the touch screen to set the values of the 3 sliders from 0 to 255. With the if statements we confine the area of each slider and get the X value of the slider. So the values of the X coordinate of each slider are from 38 to 310 pixels and we need to map these values into values from 0 to 255 which will be used as a PWM signal for lighting up the LED. If you need more details how the RGB LED works you can check my particular tutorialfor that. The rest of the code in this custom function is for drawing the sliders. Back in the loop section we only have the back button which also turns off the LED when pressed.

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: