This repository contains a program to load a BMP Image from an SD Card and display it on a 3.5" touch screen display shield with an Arduino UNO R3/R4, as shown below -
 |
 |
|---|
Most 3.5" LCD Touch displays use the ILI9486 Display Driver and include a resistive touchscreen. The PCB Layout & silkscreen text may vary slightly between displays. This does not change their behaviour and functionality. This repository depends on the following libraries -
- Adafruit Touch Screen Library to manage touch input
- Adafruit GFX Library for graphics primitives
- This fork of the MCUFriend KBV library to drive the display (this makes it compatible with the UNO R4)
The program has been written using PlatformIO, and has been tested on the Arduino UNO R3, Arduino UNO R4 Minima & Arduino UNO R4 WiFi.
The loadBMP, read16 and read32 functions in src/main.cpp have been taken from this example in the MCUFRIEND repository, for fair use and educational purposes. All code taken from other repositories belongs to their respective authors and are protected by their respective licenses.
Tip
A detailed tutorial on how to use this repository is available at https://dumblebots.com/2024/07/07/using-3-5-tft-lcd-display-with-ili9486-arduino-part-4-images-bitmaps-sd-card/. The tutorial includes a comprehensive explanation of the code and how to use it.
Since this project has been written using PlatformIO by default, simply run the following commands to fetch the libraries, build the project and upload the program -
pio pkg install
pio run
pio run --target uploadCreate a new sketch and copy the contents of src/main.cpp from this repository into the default .ino file. Create a new tab/file in the IDE named constants.h and copy the contents of src/constants.h from this repository into this file.
Install the Adafruit Touch Screen Library and Adafruit GFX Library from the Library Manager (under Sketch>Include Library>Manage Libraries...)
Download this repository as a ZIP file and install it by navigating to Sketch>Include Library>Add .ZIP Library, and selecting the downloaded file from the file explorer.
After this, you can Build and Upload the program as usual.
Format an SD Card with a FAT32 filesystem with a single drive. Load a BMP Image whose dimensions are under 320x480 into the SD Card and plug the SD Card into the slot situated on the back of the display. A BMP Image File is included in the repository in case one is not immediately available.
As soon as the program is uploaded, the display should turn red and the image should be slowly painted on the display, starting from the top-left corner.
Some common problems and their solutions -
| Problem | Solution |
|---|---|
| Display stays white after uploading program | Non-Standard Driver (not ILI9486) |
| Display not responding after touch | Try changing the order of the touch pins in src/constants.h file, i.e. swap the values of XP, YP, XM and YM |
| Compilation issues related to SPI | Update the Arduino IDE version and/or install the SPI library |
| Display Flickering/Arduino is reset automatically | Faulty Power Supply/Cable |