Feather

Feather

Manufacturer	Adafruit (and others)
Host port	USB Micro-B or USB C
Microcontroller	Various
Voltage	3.3V
Digital I/O pins	20 (typically)
I/O Voltage	3.3V
Website	learn.adafruit.com/adafruit-feather/overview

Feather is a form-factor for microcontroller boards created by Adafruit.

Several manufacturers make boards with different microcontrollers and feature sets.

Description

The boards are bigger than a Pro Micro but smaller than a traditional Arduino board.

The form factor is defined in the Feather specification.

All mainboards have a JST 2-PH battery connector, capable of both running from and charging a 3.0-3.7V LiPoly battery. GPIO pins must be compatible with 3.3V logic.

All of Adafruit's boards support Arduino, and C/C++ with GCC.

An accessory board ("hat") for a Feather is called a "FeatherWing".

Boards

Adafruit Feather

There is a large number of Adafruit Feather boards.

By convention, Adafruit Feather boards have their main characteristics as part of their name.

The first part of the name often names the microcontroller:

• Feather 32u4 boards are based on the ATMega32u4 running at 8 MHz / 3.3V, which has USB hardware and much open source firmware support.
• Feather M0 boards are based on the Atmel/Microchip SAM D21 (ATSAMD21) with a ARM Cortex-M0 @ 48 MHz. Feather M4 boards are based on the Atmel/Microchip SAM D51 (ATSAMD51) with a faster ARM Cortex-M4F core @ 120 MHz. These boards support CircuitPython. The bootloader works as a USB storage device.
• Feather nRF52840 boards use the Nordic Semiconductor nRF52840 which is capable of USB, BLE and NFC. They come with Adafruit's bootloader and Nordic's "SoftDevice" for BLE already installed.

Some Adafruit Feather boards with other microcontrollers do not have hardware that can run USB HID, but instead use a USB-to-serial chip that can only be used for loading firmware over USB. "HUZZAH32" or "WROOM32" boards are based on the ESP32 that support Bluetooth but not USB.

A board named Express has a microcontroller only, where other boards are named after their additional functional units: often a communications module capable of one or more of Bluetooth / BLE, WiFi or LoRa. Some boards come with SD-card reader, but one has a small SPI Flash chip instead.

Notable boards:

• Adafruit Feather 32u4 Bluefruit LE: ATmega32U4 @ 8 MHz, with a Nordic nRF51822 coprocessor for BLE. A fork of QMK is known to exist. The board has a reputation of high power consumption (for a wireless keyboard)
• Adafruit Feather M0 Express: ATSAMD21 and a 2 MB SPI Flash chip.
• Adafruit Feather nRF52840 Express: Nordic Semiconductor n3253840 SoC with ARM Cortex M4F @ 64 MHz and support for USB, BLE and NFC among others
• Adafruit Feather RP2040 has the Raspberry Pi RP2040 SoC with 2 ARM Cortex M0 @ 133 Mhz, USB Type C, 8 MB Flash and a STEMMA QT/Qwiic port for I²C.

SparkFun Thing Plus

The SparkFun Thing Plus boards from SparkFun have a 4-pin JST connector for their "Qwiic Connect System" for I²C.

Notable boards:

• SparkFun Thing Plus - SAMD51. ATSAMD51J20 with ARM Cortex-M4F @ 120 MHz.
• SparkFun Thing Plus - ESP32 WROOM. ESP32-WROOM MCU with dual-core Xtensa LX6 @ 240 MHz. Micro-USB but no USB HID functionality. Dual-mode Bluetooth (classic and BLE)
• SparkFun Thing Plus - Artemis: AmbiqMicro Apollo3 µC with ARM Cortex-M4F @48 MHz (96 MHz turbo). USB C but no USB HID functionality. BLE

Wio Lite

The Wio Lite boards from Seeedstudio all have USB-C.

Notable boards:

• Wio Lite MG126. ATSAMD21 µC with ARM Cortex-M0 MCU. MG126 BLE module

Particle

All Particle boards come with Nordic Semiconductor nRF52840 microcontroller which has a ARM Cortex-M4F MCU @ 64 MHz, USB device and radio capable of BLE and NFC. All Particle boards have a Micro-USB port.

Notable boards:

• Particle Xenon: nRF52840 only. Discontinued.
• Particle Boron: u-blox SARA 410 WiFi module
• Particle Argon: ESP32-D0WD WiFi coprocessor

Pinout

Note: the pinout below is the one recommended by Adafruit, and the one used for AVR ATmega32u4-based boards respectively. Boards may have more or fewer pins.

Note also that a board can be longer than standard, but are not allowed to be wider.

AVR	Function	GPIO	↑USB↑	GPIO	Function	AVR
○			(picture)	○
Reset				LiPo battery connector
+3.3V
AREF
Ground
PF7	A0	18		VBAT (from battery)
PF6	A1	19		En
PF5	A2	20		VBUS (+5V from USB port)
PF4	A3	21		13		PC7
PF1	A4	22		12		PD6
PF0	A5	23		11		PB7
PB1	SCLK	15		10		PB6
PB2	MOSI	16		9		PB5
PB3	MISO	14		6		PD7
PD2	RX	0		5		PC6
PD3	TX	1		3	SCL	PD0
Ground				2	SDA	PD1
○				○

The En pin disables the 3.3V output pin when connected to ground. Every board should have an internal pull-up allowing this pin to be disconnected.

Some boards have a GPIO pin in the corner instead of Ground.