How to Use Seeed Studio Round Display for XIAO: Examples, Pinouts, and Specs

The Seeed Studio Round Display for XIAO is a compact, circular display module designed specifically for use with the Seeed Studio XIAO series of microcontrollers. Featuring a high-resolution screen, this display is ideal for creating visually appealing projects, such as wearable devices, dashboards, and compact user interfaces. Its small form factor and compatibility with the XIAO ecosystem make it a versatile choice for hobbyists and professionals alike.

• Wearable devices (e.g., smartwatches, fitness trackers)
• Compact graphical user interfaces
• IoT dashboards and data visualization
• Gaming and interactive projects
• Educational and prototyping purposes

The following table outlines the key technical details of the Seeed Studio Round Display for XIAO:

The display module connects to the XIAO microcontroller via the following pins:

1. Wiring the Display to the XIAO Microcontroller:

   • Connect the VCC pin of the display to the 3.3V pin on the XIAO.
   • Connect the GND pin of the display to the GND pin on the XIAO.
   • Connect the SPI pins (SCL, SDA, RES, DC, CS, and BLK) to the corresponding digital pins on the XIAO as per the pin configuration table above.

2. Install Required Libraries:

   • To use the display, you need to install the Adafruit_GFX and Adafruit_GC9A01 libraries in the Arduino IDE. These libraries provide the necessary functions to control the display.

3. Upload Example Code:

   • Use the following example code to test the display:

#include <Adafruit_GFX.h>       // Graphics library for displays
#include <Adafruit_GC9A01.h>    // Driver library for GC9A01 display

// Define pin connections
#define TFT_CS   D1  // Chip Select
#define TFT_DC   D2  // Data/Command
#define TFT_RST  D3  // Reset
#define TFT_BL   D0  // Backlight (optional)

// Initialize the display
Adafruit_GC9A01 tft = Adafruit_GC9A01(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(115200);
  Serial.println("Initializing display...");

  // Initialize the display
  tft.begin();
  tft.setRotation(0);  // Set display orientation
  tft.fillScreen(0x0000);  // Clear the screen (black)

  // Turn on the backlight (if connected)
  pinMode(TFT_BL, OUTPUT);
  digitalWrite(TFT_BL, HIGH);

  // Display a test message
  tft.setTextColor(0xFFFF);  // White text
  tft.setTextSize(2);        // Text size
  tft.setCursor(20, 60);     // Set cursor position
  tft.println("Hello, XIAO!");
}

void loop() {
  // Add your custom code here
}

• Power Supply: Ensure the XIAO microcontroller is powered via a stable 3.3V source to avoid damage to the display.
• Backlight Control: The BLK pin can be connected to a PWM-capable pin on the XIAO for dimming the backlight.
• SPI Speed: The SPI communication speed can be adjusted in the library settings if you encounter display glitches.
• Library Compatibility: Always use the latest versions of the Adafruit_GFX and Adafruit_GC9A01 libraries for optimal performance.

1. Display Not Turning On:

   • Verify all connections, especially VCC and GND.
   • Ensure the backlight pin (BLK) is connected to HIGH or left unconnected.

2. No Output or Garbled Display:

   • Check the SPI connections (SCL, SDA, CS, DC, RES).
   • Ensure the correct pins are defined in the code.
   • Reduce the SPI speed in the library settings if necessary.

3. Backlight Not Working:

   • Confirm that the BLK pin is connected to a digital pin set to HIGH.
   • If dimming is required, ensure the pin supports PWM.

4. Library Errors During Compilation:

   • Ensure the Adafruit_GFX and Adafruit_GC9A01 libraries are installed and up to date.
   • Restart the Arduino IDE after installing the libraries.

Q: Can I use this display with other microcontrollers?
A: Yes, the display can be used with other microcontrollers that support SPI communication, but you may need to adjust the pin definitions and ensure compatibility with the GC9A01 driver.

Q: What is the maximum SPI speed supported by the display?
A: The GC9A01 driver typically supports SPI speeds up to 40MHz, but lower speeds may be required for stable operation depending on your setup.

Q: Can I use the display in low-power applications?
A: Yes, you can reduce power consumption by dimming the backlight or turning it off when not needed.

Q: Is the display sunlight-readable?
A: The display is not optimized for direct sunlight readability but performs well in indoor and shaded environments.