nrf52840: Nordic Semiconductor nRF52840 (nRF5 SDK)

This guide’s aim is to help you with using Contiki-NG for Nordic Semiconductor’s nRF52840 SoC.

This port supports the PCA10056 (nRF52840-DK) and PCA10059 (nRF52840-DONGLE) boards.

Port Features

The following features have been implemented:

  • Support for the 802.15.4 mode of the radio, including IPv6 using 6LoWPAN

  • Support for both TSCH and CSMA

  • No dependency on the SoftDevice

  • Contiki-NG system clock and rtimers

  • UART driver

  • Watchdog driver

  • RNG driver seeded from the hardware RNG

  • Temperature sensor driver

  • DK/Dongle LED and Button driver

  • Bootloader and DFU upload support

  • Real Time Transfer (RTT) I/O support

  • Native USB support

Note that this port does not support BLE.

The port is organized as follows:

  • nRF52840 CPU drivers are located in the arch/cpu/nrf52840 folder.

  • The nRF52 SDK is located in the arch/cpu/nrf52840/lib/nrf52-sdk folder. This will be installed automatically as a git submodule.

  • nRF52 DK and Dongle drivers are located in the arch/platform/nrf52840 folder.

Prerequisites and Setup

In order to compile for the nRF52840 platforms you’ll need:

  • An ARM compatible toolchain

The toolchain used to build Contiki-NG is arm-gcc, also used by other arm-based Contiki-NG ports.

If you use the docker image or the vagrant image, this will be pre-installed for you. Otherwise, depending on your system, please follow the respective installation instructions (native Linux / native mac OS).

  • GNU make

  • nrfjprog for programming the nRF52840 DK

nrfjprog is supplied as part of the nRF Command Line Tools and can be downloaded from the following link:

  • nrfutil for programming the nRF52840 Dongle

Follow the instructions to install nrfutil and the nrf5sdk-tools at

Getting Started

Once all tools are installed it is recommended to start by compiling and flashing examples/hello-world application. This allows to verify that toolchain setup is correct.

To compile the example, go to examples/hello-world and execute:

make TARGET=nrf52840

If the compilation is completed without errors flash the board:

make TARGET=nrf52840 hello-world.upload


This target supports all the common IPv6 examples available under the examples/ folder.

Compilation Options

The Contiki-NG TARGET name for this port is nrf52840, so in order to compile an application you need to invoke GNU make as follows:

make TARGET=nrf52840

In addition to this port supports the following variables which can be set on the compilation command line:

  • NRF52840_USE_RTT={0|1}
    Enables RealTime Terminal I/O. See VCOM and RTT for details.
    By default, RTT is disabled and IO is done using Virtual COM port.

  • NRF52840_NATIVE_USB={0|1}
    Enables the native USB port of the nRF52840 SoC.
    This will redirect I/O and SLIP to the native USB port (labelled nRF USB on the DK).
    Using the native USB port provides a performance increase when acting as a border router.
    By default, this is disabled for BOARD=dk and enabled for BOARD=dongle.

  • NRF52840_USB_DFU_TRIGGER={0|1}
    Enables the Nordic DFU trigger interface to allow for automatic reboot by nrfutil to the dongle’s bootloader when programming.
    Only available and enabled by default for BOARD=dongle.

  • NRF52_UPLOAD_SN=<serial number>
    Allows to choose a particular DK by its serial number (printed on the label).
    This is useful if you have more than one DK connected to your PC and wish to flash a particular device using the .upload target.

  • BOARD={dk|dongle}
    Allows to specify if the nRF52840 DK or Dongle is used.
    Dongle images are built with a bootloader-specific linker file and should be flashed using the .dfu-upload target.

Compilation Targets

Invoking make solely with the TARGET variable set will build all applications in a given folder. A particular application can be built by invoking make with its name as a compilation target:

make TARGET=nrf52840 hello-world 

In order to flash the application binary to a single nRF52840 DK board use <application>.upload as make target, e.g.:

make TARGET=nrf52840 hello-world.upload

In order to flash the application binary to all attached nRF52840 DK boards use <application>.upload-all as make target, e.g.:

make TARGET=nrf52840 hello-world.upload-all

In order to flash the application binary to a single nRF52840 Dongle use <application>.dfu-upload as make target, e.g.:

make TARGET=nrf52840 BOARD=dongle hello-world.dfu-upload PORT=/dev/ttyACM0

Where PORT is the name of the USB CDC-ACM port that the dongle is on.
If NRF52840_USB_DFU_TRIGGER has not been disabled, the dongle will reboot to bootloader automatically.
Otherwise the bootloader can be activated by pressing the RESET button once, until the red LED begins to pulse.

Notes when using the nRF dongle:

  • If NRF52840_NATIVE_USB is disabled, the serial output from the dongle can be accessed by attaching a USB to Serial converter to pins 0.29 (TX ->) and 0.31 (RX <-).

  • If nrfutil returns an error such as LIBUSB_ERROR_ACCESS when attempting to perform a DFU trigger the following udev rules might be required:

## Set /dev/bus/usb/*/* as read-write for all users (0666) for Nordic Semiconductor devices
SUBSYSTEM=="usb", ATTRS{idVendor}=="1915", MODE="0666"

To remove all build results invoke:

make TARGET=nrf52840 clean

Virtual COM and Real Time Transfer

By default, the nRF52840 port uses a Virtual COM port to output logs. Once the DK is plugged in a /ttyACM<n> or /ttyUSB<n> device should appear in your filesystem. A terminal emulator, such as picocom or minicom, can be used to connect to the device. Default serial port speed is 115200 bps.

When using the Virtual COM port, USB Mass Storage support must be disabled on the on-board J-Link debugger as it causes issues with serial communication (#1365):

$ JLinkExe

To connect to serial port using picocom invoke:

picocom -fh -b 115200 --imap lfcrlf /dev/ttyACM0 

In addition to Virtual COM the port supports SEGGER’s Real Time Transfer for low overhead I/O support. This allows for outputting debugging information at much higher rate with significantly lower overhead than regular I/O.

To compile an application with RTT rather that VCOM set NRF52840_USE_RTT to 1 on the compilation command line:

make TARGET=nrf52840 NRF52840_USE_RTT=1 hello-world

You can then connect to the device terminal using JLinkRTTClient. Note that a JLlink gdb or commander must be connected to the target for the RTT to work.

More details regarding RTT can be found at


For bug reports or/and suggestions please open a github issue.


All files in the port are under BSD license. The nRF52 SDK is licensed on a separate terms.