nRF52 Adafruit Feather

Overview

The nRF52 Adafruit Bluefruit Feather hardware provides support for the Nordic Semiconductor nRF52832 ARM Cortex-M4F CPU and the following devices:

  • NVIC

  • RTC

  • UART

  • GPIO

  • FLASH

  • RADIO (Bluetooth Low Energy)

  • Segger RTT (RTT Console)

nRF52 Adafruit Feather Board

nRF52 Adafruit Feather Board (Credit: Adafruit)

More information about the board and its features can be found at the Adafruit Feather nRF52 Bluefruit Learning Guide [1]. The Nordic Semiconductor Infocenter [4] contains the processor’s information and the datasheet.

Hardware

  • nRF52832 ARM Cortex-M4F processor at 64 MHz

  • 32.768 kHz crystal oscillator

  • 512 KiB flash memory and 64 KiB of SRAM

  • Battery connector and charger for 3.7 V lithium polymer batteries

  • Charging indicator LED

  • 2 User LEDs

  • Reset button

  • SWD connector

  • USB serial converter

Supported Features

The nRF52 Adafruit Feather board configuration supports the following hardware features:

Interface

Controller

Driver/Component

NVIC

on-chip

nested vectored interrupt controller

RTC

on-chip

system clock

UART

on-chip

serial port

GPIO

on-chip

gpio

FLASH

on-chip

flash

RADIO

on-chip

Bluetooth

RTT

on-chip

console

Other hardware features have not been enabled yet for this board.

Connections and IOs

The Adafruit Feather nRF52 Bluefruit Learning Guide [1] has detailed information about the board including pinouts [3] and the schematic [2].

LED

  • LED0 (red) = P0.17

  • LED1 (blue) = P0.19

Push buttons

  • DFU = SW0 = P0.20

  • RESET = SW1 = P0.21/reset

Programming and Debugging

The nrf52_adafruit_feather board is available in two different versions:

Applications for the nrf52_adafruit_feather board configuration can be built, flashed, and debugged in the usual way. See Building an Application and Run an Application for more details on building and running.

Flashing

Flashing Zephyr onto the nrf52_adafruit_feather board requires an external J-Link programmer. The programmer is attached to the X1 SWD header.

Follow the instructions in the Nordic nRF5x Segger J-Link page to install and configure all the necessary software. Further information can be found in Flashing. Then build and flash applications as usual (see Building an Application and Run an Application for more details).

Here is an example for the Hello World application.

  1. Build the Zephyr kernel and the Hello World sample application:

    west build -b nrf52_adafruit_feather samples/hello_world
    
  2. Connect the Adafruit nRF52 Feather to your host computer using USB

  3. Run your favorite terminal program to listen for output.

    $ minicom -D <tty_device> -b 115200
    

    Replace <tty_device> with the port where the nRF52 Adafruit Feather board can be found. For example, under Linux, /dev/ttyUSB0.

  4. Flash the image:

    west build -b nrf52_adafruit_feather samples/hello_world
    west flash
    

    You should see “Hello World! nrf52_adafruit_feather” in your terminal.

Debugging

The nrf52_adafruit_feather board does not have an on-board J-Link debug IC as some nRF5x development boards, however, instructions from the Nordic nRF5x Segger J-Link page also apply to this board, with the additional step of connecting an external debugger.

Testing the LEDs and buttons on the nRF52 Adafruit Feather

There are several samples that allow you to test that the buttons (switches) and LEDs on the board are working properly with Zephyr:

You can build and flash the examples to make sure Zephyr is running correctly on your board. The button and LED definitions can be found in boards/arm/nrf52_adafruit_feather/board.h.

References