The Swan MCU

The most extensible Feather-compatible MCU on the market, ready for the demands of real-world applications.

Swan MCU

An MCU built for the Notecard

  • Feather-compatible dev board, powered by an STM32L4+ @ 120 MHz with 2MB of Flash and 640KB of RAM
  • Expandable to 55 pins for access to additional I/O and buses
  • Plenty of Flash and RAM for edge ML workloads or complex applications
  • Support for C/C++, Arduino, and CircuitPython
  • CORTEX Debug connector, enabling the use of Visual Studio Code, IAR, and STM32CubeIDE with optional SWD programmer

Fly from POC to Production with Swan

Swan supported languages
Code your Way
Programmable via USB for Arduino and CircuitPython or an STLink for C/C++
Debug with Ease
Step-debug your Arduino or C/C++ code with an STLink programmer
Harness the Power
Access 55 pins on the STM32L4 via castellated edges and the Swan carrier board

Choose your Swan and Fly

The Swan is available as a Feather-ready board, part of a kit, or for embedded into a design for complete pin access.
Notecarrier AF with Swan Feather MCU

Feather Starter Kit for Swan

Includes a Notecarrier-AF, Blues Swan Feather, and a Notecard SoM with cellular.
Swan with carrier board

Swan with Swan Carrier

Includes a Blues Swan with carrier board for full 55-pin access to the Swan MCU.

Frequently Asked Questions

    Does the Swan require a Notecard?

    No! Swan is a standalone Feather-compatible MCU that can be used with FeatherWings, other Feather-based projects, and/or independently from the Notecard and Notecarriers.

    How can I get started with the Swan?

    Once you receive your Swan, you can follow the guides at to get started.

    Does the Swan require a CORTEX SWD Programmer?

    No, but we recommend getting one! Swan can be programmed over USB for both Arduino and CircuitPython use, but a programmer is required for using IAR or STM32CubeIDE. If you’re interested in step-debugging in VSCode, IAR, or STM32CubeIDE, an STLINK programmer is required, and we have an inexpensive option in the store.

    How can I access the additional GPIOs on the Swan's core STM32L4 MCU?

    The Swan embedded board is a single-sided PCB that includes a set of castellations to bring 55 I/O, power and ground pins from the STM32L4 on the board out to the edge. To access these pins, you can solder the Swan embedded to the Swan carrier board, or design your own PCB that leverages these pins.

    When do you expect the Swan Feather to start shipping to customers?

    The Swan Feather Kit, which includes the Notecarrier-AF, a Notecard, and Swan Feather is currently available for pre-order. We expect to begin delivering pre-orders on a first-come-first-served basis in late Oct 2021.

    Where is the Swan Datasheet?

    The Swan Datasheet is available at

    Can I use the Swan for Edge ML Workloads?

    Yes! If you’re interested in doing Edge ML or tinyML with Swan, you’ll find that its 120 MHz clock speed, 2MB of Flash and 640KB of RAM make it a great board for on-device inferencing. To learn more, check out our guide on using Swan with Edge Impulse.

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