Adafruit ESP32-C6 Feather - STEMMA QT

2 grouped source records remain in the details; diagram pads use verified individual pin evidence.

USB-C port
USB-C connector used for powering and programming the board; USB power charges the LiPoly battery when connected.
Type · PowerVoltage · USB 5V input on USB pin when connected
LiPoly JST 2-PH
2-pin JST-PH connector for a 250mAh or larger 3.7/4.2V LiPoly battery; charges from USB when connected.
Type · PowerVoltage · 3.7/4.2V LiPoly battery
GND
Common ground for power and logic.
Type · GroundVoltage · 0V
BAT
Positive voltage to/from the 2-pin JST battery jack.
Type · PowerVoltage · Battery positive, 3.7/4.2V LiPoly context
USB
Positive voltage to/from the USB-C jack when USB is connected.
Type · USBVoltage · USB 5V when connected
EN
3.3V regulator enable; pulled up, connect to ground to disable the 3.3V regulator.
Type · ControlVoltage · 3.3V regulator enable logic
3.3V
Output from the 3.3V regulator; Adafruit states the pins can supply 500mA peak.
Type · PowerVoltage · 3.3V output, 500mA peak
A0-A5
Six analog-capable Feather pins; the ESP32-C6 Feather does not have a DAC, so no true analogue output.
Type · AnalogVoltage · 3.3V logic
IO21SCK
SPI clock pin, mapped to ESP32-C6 IO21.
Type · GPIO, SPIVoltage · 3.3V logic
IO22MOSI
SPI microcontroller out / sensor in pin, mapped to ESP32-C6 IO22.
Type · GPIO, SPIVoltage · 3.3V logic
IO23MISO
SPI microcontroller in / sensor out pin, mapped to ESP32-C6 IO23.
Type · GPIO, SPIVoltage · 3.3V logic
IO17RX
UART receive pin, mapped to ESP32-C6 IO17; connect to TX on the other device.
Type · GPIO, UARTVoltage · 3.3V logic
IO16TX
UART transmit pin, mapped to ESP32-C6 IO16; connect to RX on the other device.
Type · GPIO, UARTVoltage · 3.3V logic
IO18SCL
I2C clock pin, mapped to ESP32-C6 IO18, shared by the STEMMA QT connector and has a 5k pullup.
Type · GPIO, I2CVoltage · 3.3V logic with pullup
IO19SDA
I2C data pin, mapped to ESP32-C6 IO19, shared by the STEMMA QT connector and has a 5k pullup.
Type · GPIO, I2CVoltage · 3.3V logic with pullup
STEMMA QT
JST SH 4-pin STEMMA QT connector breaking out I2C SCL, SDA, 3.3V, and GND.
Type · UnknownVoltage · 3.3V I2C connector
IO20NEOPIXEL_I2C_POWER
Power-control pin that must be pulled high for the STEMMA QT connector and onboard NeoPixel power.
Type · GPIO, ControlVoltage · 3.3V logic control
IO0, IO5-IO9, IO12, IO15
Digital pins; IO9 is shared with the Boot button and onboard NeoPixel, IO6 with A2, and IO5 with A3.
Type · GPIOVoltage · 3.3V logic
IO9NeoPixel
Onboard RGB NeoPixel LED labelled Neo; controlled from IO9 and shared with the Boot button.
Type · GPIO, USBVoltage · 3.3V logic control
IO15Red LED
Onboard red LED labelled 15, controllable in code as board.LED / LED_BUILTIN / 15.
Type · GPIO, USBVoltage · 3.3V logic control
RST
Reset pin tied to the reset button; tie to ground manually to reset the board.
Type · ControlVoltage · 3.3V logic reset
IO9Boot
Boot button input connected to IO9; also used for ROM bootloader mode and shared with the onboard NeoPixel.
Type · GPIO, ControlVoltage · 3.3V logic input with pullup use

Pin	Type	Function	Voltage
USB-C port	Power	USB-C connector used for powering and programming the board; USB power charges the LiPoly battery when connected.	USB 5V input on USB pin when connected
LiPoly JST 2-PH	Power	2-pin JST-PH connector for a 250mAh or larger 3.7/4.2V LiPoly battery; charges from USB when connected.	3.7/4.2V LiPoly battery
GND	Ground	Common ground for power and logic.	0V
BAT	Power	Positive voltage to/from the 2-pin JST battery jack.	Battery positive, 3.7/4.2V LiPoly context
USB	USB	Positive voltage to/from the USB-C jack when USB is connected.	USB 5V when connected
EN	Control	3.3V regulator enable; pulled up, connect to ground to disable the 3.3V regulator.	3.3V regulator enable logic
3.3V	Power	Output from the 3.3V regulator; Adafruit states the pins can supply 500mA peak.	3.3V output, 500mA peak
A0-A5	Analog	Six analog-capable Feather pins; the ESP32-C6 Feather does not have a DAC, so no true analogue output.	3.3V logic
IO21SCK	GPIO, SPI	SPI clock pin, mapped to ESP32-C6 IO21.	3.3V logic
IO22MOSI	GPIO, SPI	SPI microcontroller out / sensor in pin, mapped to ESP32-C6 IO22.	3.3V logic
IO23MISO	GPIO, SPI	SPI microcontroller in / sensor out pin, mapped to ESP32-C6 IO23.	3.3V logic
IO17RX	GPIO, UART	UART receive pin, mapped to ESP32-C6 IO17; connect to TX on the other device.	3.3V logic
IO16TX	GPIO, UART	UART transmit pin, mapped to ESP32-C6 IO16; connect to RX on the other device.	3.3V logic
IO18SCL	GPIO, I2C	I2C clock pin, mapped to ESP32-C6 IO18, shared by the STEMMA QT connector and has a 5k pullup.	3.3V logic with pullup
IO19SDA	GPIO, I2C	I2C data pin, mapped to ESP32-C6 IO19, shared by the STEMMA QT connector and has a 5k pullup.	3.3V logic with pullup
STEMMA QT	Unknown	JST SH 4-pin STEMMA QT connector breaking out I2C SCL, SDA, 3.3V, and GND.	3.3V I2C connector
IO20NEOPIXEL_I2C_POWER	GPIO, Control	Power-control pin that must be pulled high for the STEMMA QT connector and onboard NeoPixel power.	3.3V logic control
IO0, IO5-IO9, IO12, IO15	GPIO	Digital pins; IO9 is shared with the Boot button and onboard NeoPixel, IO6 with A2, and IO5 with A3.	3.3V logic
IO9NeoPixel	GPIO, USB	Onboard RGB NeoPixel LED labelled Neo; controlled from IO9 and shared with the Boot button.	3.3V logic control
IO15Red LED	GPIO, USB	Onboard red LED labelled 15, controllable in code as board.LED / LED_BUILTIN / 15.	3.3V logic control
RST	Control	Reset pin tied to the reset button; tie to ground manually to reset the board.	3.3V logic reset
IO9Boot	GPIO, Control	Boot button input connected to IO9; also used for ROM bootloader mode and shared with the onboard NeoPixel.	3.3V logic input with pullup use

2 grouped source records remain in the details; diagram pads use verified individual pin evidence.

Pin details

22 connections

USB-C port
USB-C connector used for powering and programming the board; USB power charges the LiPoly battery when connected.
PowerVoltage · USB 5V input on USB pin when connected
LiPoly JST 2-PH
2-pin JST-PH connector for a 250mAh or larger 3.7/4.2V LiPoly battery; charges from USB when connected.
PowerVoltage · 3.7/4.2V LiPoly battery
GND
Common ground for power and logic.
GroundVoltage · 0V
BAT
Positive voltage to/from the 2-pin JST battery jack.
PowerVoltage · Battery positive, 3.7/4.2V LiPoly context
USB
Positive voltage to/from the USB-C jack when USB is connected.
USBVoltage · USB 5V when connected
EN
3.3V regulator enable; pulled up, connect to ground to disable the 3.3V regulator.
ControlVoltage · 3.3V regulator enable logic
3.3V
Output from the 3.3V regulator; Adafruit states the pins can supply 500mA peak.
PowerVoltage · 3.3V output, 500mA peak
A0-A5
Six analog-capable Feather pins; the ESP32-C6 Feather does not have a DAC, so no true analogue output.
AnalogVoltage · 3.3V logic
IO21SCK
SPI clock pin, mapped to ESP32-C6 IO21.
GPIO, SPIVoltage · 3.3V logic
IO22MOSI
SPI microcontroller out / sensor in pin, mapped to ESP32-C6 IO22.
GPIO, SPIVoltage · 3.3V logic
IO23MISO
SPI microcontroller in / sensor out pin, mapped to ESP32-C6 IO23.
GPIO, SPIVoltage · 3.3V logic
IO17RX
UART receive pin, mapped to ESP32-C6 IO17; connect to TX on the other device.
GPIO, UARTVoltage · 3.3V logic
IO16TX
UART transmit pin, mapped to ESP32-C6 IO16; connect to RX on the other device.
GPIO, UARTVoltage · 3.3V logic
IO18SCL
I2C clock pin, mapped to ESP32-C6 IO18, shared by the STEMMA QT connector and has a 5k pullup.
GPIO, I2CVoltage · 3.3V logic with pullup
IO19SDA
I2C data pin, mapped to ESP32-C6 IO19, shared by the STEMMA QT connector and has a 5k pullup.
GPIO, I2CVoltage · 3.3V logic with pullup
STEMMA QT
JST SH 4-pin STEMMA QT connector breaking out I2C SCL, SDA, 3.3V, and GND.
UnknownVoltage · 3.3V I2C connector
IO20NEOPIXEL_I2C_POWER
Power-control pin that must be pulled high for the STEMMA QT connector and onboard NeoPixel power.
GPIO, ControlVoltage · 3.3V logic control
IO0, IO5-IO9, IO12, IO15
Digital pins; IO9 is shared with the Boot button and onboard NeoPixel, IO6 with A2, and IO5 with A3.
GPIOVoltage · 3.3V logic
IO9NeoPixel
Onboard RGB NeoPixel LED labelled Neo; controlled from IO9 and shared with the Boot button.
GPIO, USBVoltage · 3.3V logic control
IO15Red LED
Onboard red LED labelled 15, controllable in code as board.LED / LED_BUILTIN / 15.
GPIO, USBVoltage · 3.3V logic control
RST
Reset pin tied to the reset button; tie to ground manually to reset the board.
ControlVoltage · 3.3V logic reset
IO9Boot
Boot button input connected to IO9; also used for ROM bootloader mode and shared with the onboard NeoPixel.
GPIO, ControlVoltage · 3.3V logic input with pullup use

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