How to Use Round TFT LCD: Examples, Pinouts, and Specs

The Round TFT LCD (GC9A01) by Arduinp is a Thin-Film Transistor Liquid Crystal Display designed for rendering high-quality visual information in a unique circular form factor. This display is ideal for wearable devices, smart home applications, and any project where a traditional rectangular screen may not fit the aesthetic or functional requirements.

• Smartwatches and wearable technology
• Custom user interfaces for IoT devices
• Automotive dashboard displays
• Creative projects requiring a non-traditional display shape

• Display Type: Round TFT LCD
• Resolution: 240 x 240 pixels
• Display Diameter: 1.28 inches
• Interface: SPI (Serial Peripheral Interface)
• Supply Voltage: 3.3V - 5V
• Logic Level Voltage: 3.3V (5V tolerant)
• Operating Temperature: -20°C to 70°C

1. Power Connections: Connect the VCC pin to a 3.3V or 5V power supply and the GND pin to the ground.
2. SPI Interface: Connect SCL and SDA to the corresponding SPI clock and data lines on your microcontroller.
3. Control Pins: Connect the RES, DC, and CS pins to available digital I/O pins on your microcontroller.
4. Backlight Control (Optional): Connect the BLK pin to a PWM-capable pin if you wish to control the backlight brightness.

• Always ensure that the power supply voltage matches the specifications to prevent damage.
• Use a level shifter if your microcontroller operates at a different logic level than the display.
• Avoid exposing the display to extreme temperatures or humidity.
• When handling the display, take precautions against electrostatic discharge (ESD).

#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_GC9A01.h>

// Pin definitions
#define TFT_CS        10
#define TFT_RST       9
#define TFT_DC        8
#define TFT_BL        6 // Optional: control backlight

Adafruit_GC9A01 tft = Adafruit_GC9A01(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  tft.begin();
  tft.setRotation(2); // Adjust according to your mounting

  // Optional: control backlight
  pinMode(TFT_BL, OUTPUT);
  analogWrite(TFT_BL, 128); // Set half brightness
}

void loop() {
  tft.fillScreen(GC9A01_BLACK);
  tft.setCursor(0, 0);
  tft.setTextColor(GC9A01_WHITE);
  tft.setTextSize(1);
  tft.print("Hello, World!");
  delay(1000);
}

• Display not powering on: Check the power connections and ensure the voltage is within the specified range.
• No image or incorrect colors: Verify that the SPI connections are correct and that the correct pins are defined in your code.
• Dim or flickering backlight: Ensure that the BLK pin is connected properly and that the PWM signal is within the acceptable range.

• Double-check all connections against the pin configuration table.
• Use example code to test the display functionality before integrating it into your project.
• If using PWM for backlight control, start with a lower duty cycle and increase gradually to find the optimal brightness.

Q: Can I use this display with a 5V microcontroller? A: Yes, the display is 5V tolerant, but it is recommended to use a level shifter for SPI signals.

Q: How can I invert the display colors? A: Most graphics libraries, like Adafruit_GFX, provide functions to invert colors. Check the library documentation for the specific command.

Q: Is it possible to display images or animations? A: Yes, the display is capable of showing images and animations. You will need to use a library that supports the GC9A01 and convert your images to the appropriate format.

Q: What should I do if the display is not responding? A: Verify all connections, ensure that the correct pins are used in the code, and reset the power to the display. If the issue persists, consult the manufacturer's datasheet and support forums.