Adafruit Feather nRF52840 Express


Adafruit Feather nRF52840 Express Adafruit Store

  • Cortex-M4 processor 64MHz
  • 1 MB of FLASH and 256KB of SRAM
  • Arduino IDE support, CircuitPython support
  • BLE Nordic SoftDevice radio stack
  • pre-programed the chip with our UF2 bootloader, which can use either commandline UART programming with nrfutil
  • 21 GPIO, 6 x 12-bit ADC pins, up to 12 PWM outputs (3 PWM modules with 4 outputs each)
  • Pin #3 red LED for general purpose blinking, NeoPixel for colorful feedback
  • Battery connector with USB battery charging and with analog pin to measure battery voltage

How to use it with CircuitPython

CircuitPython a derivative of MicroPython that runs on the Adafruit microcontrollers. It’s designed to lower the barrier for entry to learning programming and electronics.

The chip comes with pre-programed UF2 bootloader which allows you to drag-n-drop CircuitPython files onto the mass storage.

To install CircuitPython double-click the reset button of the Feather, it will then mount as mass storage on your computer. Copy the latest UF2 file from onto it. It will restart and then show a new drive called CIRCUITPY.

On the mounted CIRCUITPY mass storage you now find a python file where you can put your code. And thats it! Check out the link for Getting Started with CircuitPython and Bluetooth Low Energy

Some of the example code requires additional libraries, you can download the latest matching CircuitPython library bundle from GitHub. From there manually copy the ones you need into the mounted lib folder.


  • Do not connect anything to it with more than 3.3V
  • Red LED is board.D3
  • I2C Pins need a pullup resistor