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The Adafruit Feather STM32F405 Express brings STM32 power to the Feather ecosystem, running CircuitPython at a blistering 168 MHz — making it one of the fastest CircuitPython-capable Feather boards. With 1 MB of flash, 192 KB of SRAM, USB Type C, an SDIO-connected SD card slot, and a STEMMA QT connector, it packs serious capability into the standard Feather form factor.

Most pins on this 3.3 V board are 5 V tolerant, making it straightforward to interface with a wide range of sensors and peripherals. The built-in USB DFU bootloader is used for firmware loading (this board does not use a UF2 bootloader).

Key Features

  • STM32F405 Cortex-M4 – 168 MHz with FPU, 1 MB flash, 192 KB SRAM
  • USB Type C – Power and data; uses built-in USB DFU bootloader for firmware loading
  • MicroSD Card Slot – Connected via SDIO on the bottom of the board
  • 2 MB SPI Flash – For CircuitPython code and file storage
  • STEMMA QT / Qwiic Connector – Plug-and-play I2C sensor connectivity with no soldering
  • Built-in NeoPixel – RGB status indicator
  • LiPo Connector and Charger – Built-in battery management
  • 5 V Tolerant Pins – Most GPIO pins accept 5 V logic levels
  • Rich Peripherals – I2C, UART, SPI, multiple ADCs, and DACs

Programming Support

  • CircuitPython – Digital IO, analogue in/out, I2C, SPI, and PWM supported; SDIO SD card and DisplayIO are not yet supported natively
  • Arduino – Supported via STM32duino; no auto-reset bootloader yet, so you must pull the BOOT0 pin high and manually reset before uploading
  • MicroPython – Solid support, though Adafruit does not provide MicroPython sensor libraries
Note: Compatible with nearly all FeatherWings. The RFM69/RFM9x radio FeatherWings are not supported due to platform-specific library requirements.

Ideal For

  • High-performance CircuitPython projects requiring fast execution
  • Data logging with the built-in MicroSD slot
  • Projects requiring 5 V tolerant GPIO
  • Battery-powered embedded applications

Package Contents

  • 1× Adafruit Feather STM32F405 Express

The Adafruit Feather STM32F405 Express appears in the following collections:

SKU AF-4382