How to Use ILI9341 TFT display: Examples, Pinouts, and Specs

The ILI9341 TFT display is a versatile and colorful display module commonly used in embedded systems and DIY electronics projects. It features a Thin Film Transistor (TFT) screen that is capable of displaying full-color graphics and text. The display is driven by the ILI9341 controller, which facilitates communication between the display and a microcontroller, such as an Arduino UNO, through a Serial Peripheral Interface (SPI) or 8/16-bit parallel interface.

• User interfaces for embedded systems
• Display output for sensors and data
• Portable game consoles
• DIY smartwatches
• Home automation control panels

• Display Size: Typically 2.4 to 3.2 inches diagonally
• Resolution: 240x320 pixels
• Interface: SPI / 8/16-bit parallel
• Color Depth: 16-bit (65,536 colors)
• Operating Voltage: 3.3V (5V tolerant with level shifters)
• Logic Level: 3.3V

1. Power Connections: Connect VCC to 3.3V and GND to the ground of your power supply. If using with a 5V system like an Arduino UNO, ensure you use level shifters or voltage regulators to avoid damaging the display.

2. Data Connections: For SPI communication, connect the SDI/MOSI, SCK, and SDO/MISO (if reading from the display) to the corresponding SPI pins on your microcontroller.

3. Control Pins: Connect CS to the chip select pin, RESET to the reset pin, and DC/RS to the data/command pin on your microcontroller.

4. Backlight: Connect LED to a digital pin for backlight control or directly to 3.3V for constant backlight.

• Always check the voltage levels to prevent damage to the display.
• Use a current limiting resistor with the LED pin if connecting directly to a power source.
• Avoid exposing the display to direct sunlight or high temperatures to prevent damage.
• When using SPI, ensure that the SPI mode and clock speed are correctly set for the ILI9341.

#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ILI9341.h> // Hardware-specific library

// For the Adafruit shield, these are the default.
#define TFT_CS     10
#define TFT_RST    9  // You can also connect this to the Arduino reset
                      // in which case, set this #define pin to -1!
#define TFT_DC     8

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  Serial.begin(9600);
  tft.begin();

  // Make sure the orientation is correct
  tft.setRotation(1);

  // Fill the screen with black color
  tft.fillScreen(ILI9341_BLACK);
}

void loop() {
  // Check the Adafruit GFX library for more graphics functions
  tft.setCursor(0, 0);
  tft.setTextColor(ILI9341_WHITE);  
  tft.setTextSize(1);
  tft.println("Hello, World!");
}

• Display not powering on: Check the power connections and ensure the voltage is 3.3V.
• No display output: Verify that the SPI connections are correct and the chip select pin is being controlled properly.
• Distorted images or text: Ensure that the library and microcontroller are configured for the correct SPI mode and clock speed.

• Double-check wiring, especially the SPI and control pins.
• Make sure that the correct driver library (Adafruit_ILI9341) is installed in your Arduino IDE.
• Reset the display by toggling the RESET pin if the display is not responding correctly.

Q: Can I use the ILI9341 display with a 5V microcontroller?

A: Yes, but you must use level shifters or voltage regulators to bring the logic levels down to 3.3V to avoid damaging the display.

Q: How can I control the brightness of the display?

A: The brightness can be controlled by applying PWM to the LED backlight pin.

Q: What should I do if I see white dots or lines on the display?

A: White dots or lines can indicate a faulty connection or a damaged display. Check the connections first, and if the problem persists, the display may need to be replaced.