GC9D01 160x160 Round TFT Module

A 0.71 inch round TFT display driven by a GC9D01 controller. Many listings sell this as a "GC9A01" - the two chips share a similar command set but have different init sequences. Using the wrong driver gives vertical lines or incorrect colours. The size is the giveaway: GC9A01 is 240x240, GC9D01 is 160x160.

Pin reference

Module Pin	Function	Connect to
GND	Ground	GND
VDD	Power	3.3V only
SCL	SPI clock	GPIO18 (ESP32)
SDA	SPI data (MOSI)	GPIO23 (ESP32)
RES	Reset	GPIO4 (ESP32)
DC	Data / command select	GPIO27 (ESP32)
CS	Chip select	GPIO5 (ESP32)
BL	Backlight	3.3V (always-on)

Important notes

• 3.3V only - this module has no onboard voltage regulator. 5V will damage it.
• Do not use GPIO2 for DC - it is a boot strapping pin. The display holds DC low during SPI transfers which puts the ESP32 into download mode. Use GPIO27.
• MISO not connected - SPI displays are write-only.
• BL to 3.3V - wire directly, no GPIO needed for always-on backlight.