|Manufacturer||Adafruit (and others)|
|Host port||USB Micro-B or USB C|
|Digital I/O pins||20 (typically)|
Feather is a form-factor for microcontroller boards created by Adafruit.
Several manufacturers make boards with different microcontrollers and feature sets.
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".
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.
- 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.
- 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
The Wio Lite boards from Seeedstudio all have USB-C.
- Wio Lite MG126. ATSAMD21 µC with ARM Cortex-M0 MCU. MG126 BLE module
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.
- Particle Xenon: nRF52840 only. Discontinued.
- Particle Boron: u-blox SARA 410 WiFi module
- Particle Argon: ESP32-D0WD WiFi coprocessor
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.
|Reset||LiPo battery connector|
|PF7||A0||18||VBAT (from battery)|
|PF5||A2||20||VBUS (+5V from USB port)|
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.