The Complete Guide to the 1.28-Inch GC9A01 Round TFT Display Module -

Circular displays are a unique twist for DIY electronics projects. While most LCDs are square or rectangular, the 1.28-inch round TFT display gives your project a modern, smartwatch-like look. It’s based on the GC9A01 controller, offers a 240×240 full-color IPS panel, and connects over SPI. In this guide we’ll explore what it is, how to wire it, how to drive it, and where it shines.

What is the GC9A01 Round TFT?

The module is a 1.28-inch IPS LCD in a round form factor, with a resolution of 240×240 pixels and support for 65k/262k colors (16-bit/18-bit). It uses the GC9A01 controller IC, which is well supported in Arduino and ESP32 libraries (such as TFT_eSPI and Adafruit_GFX).

Unlike OLED displays, this module uses an LED backlight, giving good brightness and visibility. IPS technology provides wide viewing angles and vivid colors — essential if the display might be seen from different sides.

Why use it?

Round form factor = ideal for clocks, gauges, meters, wearables.
IPS panel = better color and contrast than older TFTs.
Compact, but still 240×240 pixels = crisp graphics.
Works via SPI, so it’s easy to connect to ESP32, Arduino, STM32, Raspberry Pi, etc.

Key Specifications

Parameter	Value
Display type	1.28″ round IPS TFT LCD
Resolution	240×240 pixels
Driver IC	GC9A01
Interface	SPI (4-wire)
Colors	65k / 262k
Viewing angle	~80° all directions (IPS)
Supply voltage	3.3V (logic + VCC)
Backlight	Integrated white LED (driven via pin)
Active area	~32.4 mm diameter
Module size	~40 mm diameter (with PCB adapter)

Pinout and Wiring

The module usually comes mounted on a small PCB adapter with labeled pins. Here’s the standard pinout:

Pin	Name	Function
1	VCC	3.3V power
2	GND	Ground
3	SCL (SCK)	SPI Clock
4	SDA (MOSI)	SPI Data (Master Out, Slave In)
5	RES	Reset pin
6	DC (A0)	Data/Command select
7	CS	Chip Select
8	BLK	Backlight control (PWM or tied high for always on)

Example Wiring with ESP32

VCC → 3.3V
GND → GND
SCL → GPIO18 (default SPI clock)
SDA → GPIO23 (default MOSI)
RES → GPIO4
DC → GPIO2
CS → GPIO5
BLK → GPIO15 (or tie to 3.3V for always on backlight)

Note: The module is not 5V tolerant. Always run at 3.3V logic.

Using with Arduino / ESP32

There are multiple libraries that support the GC9A01 controller. The two most popular:

Adafruit_GFX + Adafruit_GC9A01A library
Bodmer’s TFT_eSPI (faster, highly configurable, great for ESP32)

Example Code with Adafruit Library

#include <Adafruit_GFX.h>
#include <Adafruit_GC9A01A.h>
#include <SPI.h>

// Define pins
#define TFT_CS    5
#define TFT_DC    2
#define TFT_RST   4

Adafruit_GC9A01A tft(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  Serial.begin(115200);
  tft.begin();
  tft.fillScreen(GC9A01A_BLACK);
  
  tft.setCursor(40, 100);
  tft.setTextColor(GC9A01A_GREEN);
  tft.setTextSize(2);
  tft.println("Hello World!");
}

void loop() {
  // Example: draw a clock face
  tft.fillCircle(120, 120, 100, GC9A01A_BLUE);
  delay(2000);
  tft.fillCircle(120, 120, 100, GC9A01A_RED);
  delay(2000);
}

Example Code with TFT_eSPI (ESP32)

Install TFT_eSPI library.
Edit User_Setup.h or use User_Setup_Select.h to define driver:

#define GC9A01_DRIVER
#define TFT_WIDTH  240
#define TFT_HEIGHT 240

#define TFT_CS   5
#define TFT_DC   2
#define TFT_RST  4
#define TFT_BL   15

Example sketch:

#include <TFT_eSPI.h>
#include <SPI.h>

TFT_eSPI tft = TFT_eSPI(); 

void setup() {
  tft.init();
  tft.setRotation(0);
  tft.fillScreen(TFT_BLACK);
  tft.setTextColor(TFT_WHITE, TFT_BLACK);
  tft.drawString("Round Display!", 40, 120, 4);
}

void loop() {
  tft.fillCircle(120, 120, 100, TFT_GREEN);
  delay(1000);
  tft.fillCircle(120, 120, 100, TFT_RED);
  delay(1000);
}

Practical Tips

Frame rate: With SPI, updates aren’t lightning fast. For smooth animation, use ESP32 or STM32 with SPI at higher MHz.
Backlight control: Use PWM on BLK pin for brightness control (dimming / saving power).
Graphics libraries: Use TFT_eSPI if you need speed and advanced features (sprites, smooth gauges, anti-aliased fonts).
Mounting: The round shape is perfect for enclosures — but remember the PCB is square. For wearables, you might design a circular cutout while hiding the PCB edges.
Power: Keep VCC and logic strictly at 3.3V. Use a regulator if powered from 5V.

Project Ideas

Here are some real-world uses for this round TFT:

Smartwatch / wearable: time, notifications, step count, etc.
Digital gauge: RPM, temperature, battery level (for bikes, cars, drones).
Analog clock face: with smooth hands, customizable watch faces.
Weather station display: show temperature, humidity, forecast icons.
IoT dashboard: show Wi-Fi status, sensor values, system info.

Conclusion

The 1.28-inch round GC9A01 TFT display is a great choice if you want something more stylish than a square LCD. With 240×240 resolution, bright IPS colors, and solid library support, it’s easy to bring beautiful GUIs, clocks, or dashboards into your project. Combine it with ESP32 and TFT_eSPI, and you can create smooth, modern interfaces on a budget.