Feather nRF52840 (Express, Sense)

Overview

The Adafruit Feather nRF52840 provides support for the Nordic Semiconductor nRF52840 ARM Cortex-M4F CPU and the following devices:

  • ADC

  • CLOCK

  • FLASH

  • GPIO

  • I2C

  • MPU

  • NVIC

  • PWM

  • RADIO (Bluetooth Low Energy and 802.15.4)

  • RTC

  • Segger RTT (RTT Console)

  • SPI

  • UART

  • USB

  • WDT

Adafruit Feather nRF52840 Express

Hardware

  • nRF52840 ARM Cortex-M4F processor at 64 MHz

  • 1 MB flash memory and 256 KB of SRAM

  • Battery connector and charger for 3.7 V lithium polymer batteries

  • Charging indicator LED

  • 2 User LEDs

  • 1 NeoPixel LED

  • Reset button

  • SWD connector (Express only)

  • SWD solder pads on bottom of PCB (Sense only)

  • LSM6DS33 Accel/Gyro (Sense only)

  • LIS3MDL magnetometer (Sense only)

  • APDS9960 Proximity, Light, Color, and Gesture Sensor (Sense only)

  • MP34DT01-M PDM Microphone sound sensor (Sense only)

  • SHT3X Humidity sensor (Sense only)

  • BMP280 temperature and barometric pressure/altitude (Sense only)

Supported Features

The adafruit_feather_nrf52840 board supports the hardware features listed below.

on-chip / on-board
Feature integrated in the SoC / present on the board.
2 / 2
Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo
Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

Connections and IOs

The Adafruit Feather nRF52840 Express Learn site [1] has detailed information about the board including pinouts (Express) [2] and the schematic (Express) [3].

LED

  • LED0 (red) = P1.15 (Express)

  • LED0 (red) = P1.9 (Sense)

  • LED1 (blue) = P1.10

Push buttons

  • SWITCH = P1.02

  • RESET = P0.18

Programming and Debugging

The adafruit_feather_nrf52840 board supports the runners and associated west commands listed below.

flash debug

Flashing

Flashing Zephyr onto both the Feather nRF52840 Express and Sense is possible using the SWD headers. Only the Express board has an SWD connector however.

Both the Feather nRF52840 Express and Sense ship with the Adafruit nRF52 Bootloader [7] which supports flashing using UF2 [8]. This allows easy flashing of new images, but does not support debugging the device.

  1. Build the Zephyr kernel and the Blinky sample application.

west build -b adafruit_feather_nrf52840 samples/basic/blinky

  1. If using UF2, connect the board to your host computer using USB.

  2. Tap the reset button twice quickly to enter bootloader mode. A mass storage device named FTHR840BOOT for (Express) or FTHRSNSBOOT (Sense) should appear on the host. Ensure this is mounted.

  3. Flash the image.

west build -b adafruit_feather_nrf52840 samples/basic/blinky
west flash

  1. You should see the red LED blink.

References