How to Use TFT 1.28 ROUND DISPLAY: Examples, Pinouts, and Specs

The TFT 1.28 ROUND DISPLAY is a 1.28-inch round thin-film transistor (TFT) display that delivers high-resolution color output. Its compact size and vibrant display make it an excellent choice for applications requiring a small, visually appealing interface. This display is commonly used in smartwatches, fitness trackers, medical devices, and other compact electronic devices where space is limited but high-quality visuals are essential.

• Smartwatches and wearable devices
• Fitness trackers
• Medical monitoring equipment
• IoT devices with graphical interfaces
• Compact user interfaces for consumer electronics

Below are the key technical details of the TFT 1.28 ROUND DISPLAY:

The TFT 1.28 ROUND DISPLAY typically has an 8-pin interface. Below is the pinout and description:

1. Power Supply: Connect the VCC pin to a 3.3V power source and the GND pin to ground.
2. SPI Communication: Connect the SCL (clock) and SDA (data) pins to the corresponding SPI pins on your microcontroller.
3. Control Pins:
   • Connect the RES pin to a GPIO pin on your microcontroller for resetting the display.
   • Use the DC pin to differentiate between data and command signals.
   • Connect the CS pin to a GPIO pin to enable or disable communication with the display.
4. Backlight: Connect the BLK pin to 3.3V for constant backlight or to a PWM-capable GPIO pin for brightness control.

• Voltage Levels: Ensure all signal lines operate at 3.3V logic levels. Use a level shifter if your microcontroller operates at 5V.
• Reset Timing: Hold the RES pin low for at least 10ms during initialization to properly reset the display.
• SPI Speed: Use an SPI clock speed of up to 10MHz for optimal performance.
• Library Support: Use a compatible graphics library (e.g., Adafruit GFX or TFT_eSPI) to simplify display control and rendering.

Below is an example of how to initialize and display graphics on the TFT 1.28 ROUND DISPLAY using the Arduino IDE and the Adafruit GFX library:

#include <Adafruit_GFX.h>      // Core graphics library
#include <Adafruit_ST7789.h>  // Driver for ST7789-based displays

// Define pin connections
#define TFT_CS    10  // Chip Select pin
#define TFT_RST   9   // Reset pin
#define TFT_DC    8   // Data/Command pin

// Initialize the display object
Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);
  Serial.println("TFT 1.28 ROUND DISPLAY Test");

  // Initialize the display
  tft.init(240, 240);  // Initialize with 240x240 resolution
  tft.setRotation(0);  // Set display rotation (0-3)

  // Fill the screen with a solid color
  tft.fillScreen(ST77XX_BLACK);

  // Draw a red circle in the center of the display
  tft.fillCircle(120, 120, 60, ST77XX_RED);

  // Display text
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(2);
  tft.setCursor(50, 200);
  tft.println("Hello, World!");
}

void loop() {
  // Nothing to do here
}

• Install the Adafruit GFX and Adafruit ST7789 libraries via the Arduino Library Manager before running the code.
• Adjust the pin definitions (TFT_CS, TFT_RST, TFT_DC) to match your wiring.

1. Display Not Turning On:

   • Verify the power supply connections (VCC and GND).
   • Ensure the BLK pin is connected to 3.3V or a PWM signal.

2. No Output on the Screen:

   • Check the SPI connections (SCL, SDA, CS, DC).
   • Ensure the RES pin is properly connected and the reset timing is correct.

3. Distorted or Incorrect Graphics:

   • Verify the SPI clock speed is within the recommended range (up to 10MHz).
   • Ensure the display resolution (240x240) is correctly set in the initialization code.

4. Backlight Not Working:

   • Confirm the BLK pin is connected to 3.3V or a PWM-capable GPIO pin.
   • Check for loose or incorrect connections.

Q: Can I use this display with a 5V microcontroller?
A: Yes, but you must use level shifters to convert the 5V logic signals to 3.3V.

Q: What is the maximum SPI clock speed supported?
A: The display supports SPI clock speeds of up to 10MHz.

Q: Can I dim the backlight?
A: Yes, connect the BLK pin to a PWM-capable GPIO pin and adjust the duty cycle to control brightness.

Q: Is this display compatible with Raspberry Pi?
A: Yes, the display can be used with Raspberry Pi via SPI, but you may need to configure the SPI interface and use a compatible driver.

By following this documentation, you can successfully integrate and operate the TFT 1.28 ROUND DISPLAY in your projects.