Boards / Common wiring

ESP32-S3 + GC9A01 1.28" round

240x240 round panel with CST816S single-touch. Popular for watch faces and gauges.

At a glance


Maker	Generic
MCU	ESP32-S3 Xtensa LX7 dual-core @ 240 MHz, 512 KB SRAM (+ up to 8 MB PSRAM)
Display	Galaxycore GC9A01 / GC9A01A, 240 x 240 px, SPI (4-wire serial), 16-bit colour
Touch	Hynitron CST816S (capacitive, I2C)
Backlight	GPIO 2, dimmable (PWM)
PSRAM	No
Graphics library	GFX Library for Arduino

GC9A01 / GC9A01A on SPI (4-wire serial): SPI clock 80 MHz, host SPI2_HOST, BGR colour order, inversion on.

CST816S: I2C address 0x15, 400 kHz.

Check your revision. The CST816S needs its RESET line wired or it will not answer on I2C.

Choose ESP32-S3 + GC9A01 1.28" round on the Hardware tab (or use the button above) and every pin on this page is filled in. The export writes the sketch, lcd_pins.h, the GFX Library for Arduino configuration, lv_conf.h and platformio.ini - a project that builds for this board as it comes.
The CST816S is capacitive and needs no calibration. The firmware resets it and checks it answers on every boot.
The backlight is dimmable: give a slider or a button a Set backlight action.
Screens are designed for 240 x 240 px in either orientation, with LVGL 9 or LVGL 8.

GC9A01 / GC9A01A. 1.28" round panel used for watch and gauge UIs.

CST816S. Single touch plus gestures. Standard on 1.28" round GC9A01 modules. Needs RST wired.

ESP32-S3. The only common Arduino target with a hardware RGB565 LCD peripheral. PSRAM is effectively required for RGB panels.

GFX Library for Arduino. Moshi Liu's library. Best QSPI/AMOLED and RGB coverage. Configured in code.

Nobody has published a design for this board yet. Publish yours from the designer and it appears here and in the gallery.