Adafruit QT Py ESP32-C3 WiFi Dev Board with STEMMA QT

Seeed Xiao-form-factor board with single-core RISC-V ESP32-C3 at 160 MHz, 4 MB flash, 400 KB SRAM, 2.4 GHz Wi-Fi, BLE 5.0, USB-C, and STEMMA QT I2C connector. Operates at 3.3 V; no native USB — uses the ESP32-C3's built-in USB Serial/JTAG controller.

Logical pinout · physical placement not verified

USB-C port
USB-C connector used for both powering and programming the QT Py ESP32-C3 board.
Type · PowerVoltage · USB 5V input
3.3V
Output from the 3.3V regulator. Adafruit states these pins can supply 500mA peak.
Type · PowerVoltage · 3.3V regulated output
GND
Common ground for all power and logic.
Type · GroundVoltage · 0V ground reference
5V
5V output from the USB port. Adafruit also documents using the 5V pin as a protected external voltage input with a diode.
Type · PowerVoltage · 5V USB rail; external input only with diode protection per Adafruit guidance
A0
ADC1 analog input and GPIO #4.
Type · Analog
A1
ADC1 analog input and GPIO #3.
Type · Analog
A2
ADC1 analog input and GPIO #1.
Type · Analog
A3
ADC1 analog input and GPIO #0.
Type · Analog
SCL
I2C clock pin, shared by the STEMMA QT connector. Adafruit notes there is no pull-up on this pin. GPIO #6.
Type · I2C
SDA
I2C data pin, shared by the STEMMA QT connector. Adafruit notes there is no pull-up on this pin and SDA is also an ADC2 input. GPIO #5.
Type · I2C
RX
UART receive pin. Connect to TX on a sensor or breakout. GPIO #20.
Type · UART
TX
UART transmit pin and hardware UART debug output. Connect to RX on a sensor or breakout. GPIO #21.
Type · UART
SCK
SPI clock pin. GPIO #10.
Type · SPI
MI
SPI microcontroller-in / sensor-out pin. GPIO #8.
Type · Signal
MO
SPI microcontroller-out / sensor-in pin.
Type · Signal
STEMMA QT SCL
JST SH 4-pin STEMMA QT connector I2C clock line, shared with board SCL.
Type · SignalVoltage · 3.3V logic
STEMMA QT SDA
JST SH 4-pin STEMMA QT connector I2C data line, shared with board SDA.
Type · SignalVoltage · 3.3V logic
STEMMA QT 3.3V
3.3V rail on the JST SH 4-pin STEMMA QT connector.
Type · PowerVoltage · 3.3V
STEMMA QT GND
Ground on the JST SH 4-pin STEMMA QT connector.
Type · PowerVoltage · 0V ground reference
NeoPixel
On-board RGB NeoPixel status LED, available as board.NEOPIXEL / PIN_NEOPIXEL. Adafruit states it is on GPIO #2.
Type · Signal
Boot buttonGPIO 9
Boot button for ROM bootloader mode. Adafruit states it can also be read as GPIO 9 with input pull-up.
Type · GPIO, Control
Reset button
Reset button restarts the board and helps enter the ROM bootloader.
Type · Control

Pin	Type	Function	Voltage
USB-C port	Power	USB-C connector used for both powering and programming the QT Py ESP32-C3 board.	USB 5V input
3.3V	Power	Output from the 3.3V regulator. Adafruit states these pins can supply 500mA peak.	3.3V regulated output
GND	Ground	Common ground for all power and logic.	0V ground reference
5V	Power	5V output from the USB port. Adafruit also documents using the 5V pin as a protected external voltage input with a diode.	5V USB rail; external input only with diode protection per Adafruit guidance
A0	Analog	ADC1 analog input and GPIO #4.
A1	Analog	ADC1 analog input and GPIO #3.
A2	Analog	ADC1 analog input and GPIO #1.
A3	Analog	ADC1 analog input and GPIO #0.
SCL	I2C	I2C clock pin, shared by the STEMMA QT connector. Adafruit notes there is no pull-up on this pin. GPIO #6.
SDA	I2C	I2C data pin, shared by the STEMMA QT connector. Adafruit notes there is no pull-up on this pin and SDA is also an ADC2 input. GPIO #5.
RX	UART	UART receive pin. Connect to TX on a sensor or breakout. GPIO #20.
TX	UART	UART transmit pin and hardware UART debug output. Connect to RX on a sensor or breakout. GPIO #21.
SCK	SPI	SPI clock pin. GPIO #10.
MI	Signal	SPI microcontroller-in / sensor-out pin. GPIO #8.
MO	Signal	SPI microcontroller-out / sensor-in pin.
STEMMA QT SCL	Signal	JST SH 4-pin STEMMA QT connector I2C clock line, shared with board SCL.	3.3V logic
STEMMA QT SDA	Signal	JST SH 4-pin STEMMA QT connector I2C data line, shared with board SDA.	3.3V logic
STEMMA QT 3.3V	Power	3.3V rail on the JST SH 4-pin STEMMA QT connector.	3.3V
STEMMA QT GND	Power	Ground on the JST SH 4-pin STEMMA QT connector.	0V ground reference
NeoPixel	Signal	On-board RGB NeoPixel status LED, available as board.NEOPIXEL / PIN_NEOPIXEL. Adafruit states it is on GPIO #2.
Boot buttonGPIO 9	GPIO, Control	Boot button for ROM bootloader mode. Adafruit states it can also be read as GPIO 9 with input pull-up.
Reset button	Control	Reset button restarts the board and helps enter the ROM bootloader.

Logical pinout · physical placement not verified

Pin details

22 connections

USB-C port
USB-C connector used for both powering and programming the QT Py ESP32-C3 board.
PowerVoltage · USB 5V input
3.3V
Output from the 3.3V regulator. Adafruit states these pins can supply 500mA peak.
PowerVoltage · 3.3V regulated output
GND
Common ground for all power and logic.
GroundVoltage · 0V ground reference
5V
5V output from the USB port. Adafruit also documents using the 5V pin as a protected external voltage input with a diode.
PowerVoltage · 5V USB rail; external input only with diode protection per Adafruit guidance
A0
ADC1 analog input and GPIO #4.
Analog
A1
ADC1 analog input and GPIO #3.
Analog
A2
ADC1 analog input and GPIO #1.
Analog
A3
ADC1 analog input and GPIO #0.
Analog
SCL
I2C clock pin, shared by the STEMMA QT connector. Adafruit notes there is no pull-up on this pin. GPIO #6.
I2C
SDA
I2C data pin, shared by the STEMMA QT connector. Adafruit notes there is no pull-up on this pin and SDA is also an ADC2 input. GPIO #5.
I2C
RX
UART receive pin. Connect to TX on a sensor or breakout. GPIO #20.
UART
TX
UART transmit pin and hardware UART debug output. Connect to RX on a sensor or breakout. GPIO #21.
UART
SCK
SPI clock pin. GPIO #10.
SPI
MI
SPI microcontroller-in / sensor-out pin. GPIO #8.
Signal
MO
SPI microcontroller-out / sensor-in pin.
Signal
STEMMA QT SCL
JST SH 4-pin STEMMA QT connector I2C clock line, shared with board SCL.
SignalVoltage · 3.3V logic
STEMMA QT SDA
JST SH 4-pin STEMMA QT connector I2C data line, shared with board SDA.
SignalVoltage · 3.3V logic
STEMMA QT 3.3V
3.3V rail on the JST SH 4-pin STEMMA QT connector.
PowerVoltage · 3.3V
STEMMA QT GND
Ground on the JST SH 4-pin STEMMA QT connector.
PowerVoltage · 0V ground reference
NeoPixel
On-board RGB NeoPixel status LED, available as board.NEOPIXEL / PIN_NEOPIXEL. Adafruit states it is on GPIO #2.
Signal
Boot buttonGPIO 9
Boot button for ROM bootloader mode. Adafruit states it can also be read as GPIO 9 with input pull-up.
GPIO, Control
Reset button
Reset button restarts the board and helps enter the ROM bootloader.
Control

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