Zephyr applications use the nrf52840_pca10056 board configuration to run on the nRF52840 Preview Development Kit (PCA10056) hardware. It provides support for the Nordic Semiconductor nRF52840 ARM Cortex-M4F CPU and the following devices:

  • NVIC
  • RTC
  • UART
  • GPIO
  • RADIO (Bluetooth Low Energy)
  • Segger RTT (RTT Console)
nRF52840 PCA10056 Preview DK

nRF52840 PCA10056 Preview DK (Credit: Nordic Semi)

More information about the board can be found at the nRF52840 PDK website [1]. The Nordic Semiconductor Infocenter [2] contains the processor’s information and the datasheet.


nRF52840 PDK has two external oscillators. The frequency of the slow clock is 32.768 kHz. The frequency of the main clock is 32 MHz.

Supported Features

The nrf52840_pca10056 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 are not supported by the Zephyr kernel. See nRF52840 PDK website [1] and Nordic Semiconductor Infocenter [2] for a complete list of nRF52840 Development Kit board hardware features.

Connections and IOs


  • LED1 (green) = P0.13
  • LED2 (green) = P0.14
  • LED3 (green) = P0.15
  • LED4 (green) = P0.16

Push buttons

  • BUTTON1 = SW1 = P0.11
  • BUTTON2 = SW2 = P0.12
  • BUTTON3 = SW3 = P0.24
  • BUTTON4 = SW4 = P0.25
  • BOOT = SW5 = boot/reset

Programming and Debugging

Applications for the nrf52840_pca10056 board configuration can be built and flashed in the usual way (see Build an Application and Run an Application for more details); however, the standard debugging targets are not currently available.


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 Build an Application and Run an Application for more details).

Here is an example for the Hello World application.

First, run your favorite terminal program to listen for output.

$ minicom -D <tty_device> -b 115200

Replace <tty_device> with the port where the board nRF52 DK can be found. For example, under Linux, /dev/ttyACM0.

Then build and flash the application in the usual way.

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build & cd build

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=nrf52840_pca10056 ..

# Now run ninja on the generated build system:
ninja flash


Refer to the Nordic nRF5x Segger J-Link page to learn about debugging Nordic boards with a Segger IC.

Testing the LEDs and buttons in the nRF52840 PDK

There are 2 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/nrf52840_pca10056/board.h.