.. _nrf21540dk_nrf52840: nRF21540 DK ########### Overview ******** The nRF21540 DK (PCA10112) shows possibility of the Nordic Semiconductor nRF21540 Front End Module connected with nRF52840 ARM Cortex-M4F CPU. The CPU provides support for the following devices: * :abbr:`ADC (Analog to Digital Converter)` * CLOCK * FLASH * :abbr:`GPIO (General Purpose Input Output)` * :abbr:`I2C (Inter-Integrated Circuit)` * :abbr:`MPU (Memory Protection Unit)` * :abbr:`NVIC (Nested Vectored Interrupt Controller)` * :abbr:`PWM (Pulse Width Modulation)` * RADIO (Bluetooth Low Energy and 802.15.4) * :abbr:`RTC (nRF RTC System Clock)` * Segger RTT (RTT Console) * :abbr:`SPI (Serial Peripheral Interface)` * :abbr:`UART (Universal asynchronous receiver-transmitter)` * :abbr:`USB (Universal Serial Bus)` * :abbr:`WDT (Watchdog Timer)` .. figure:: img/nrf21540dk_nrf52840.jpg :align: center :alt: nRF21540 DK nRF21540 DK (Credit: Nordic Semiconductor) More information about the board can be found at the `nRF21540 website`_. `nRF21540 Product Specification`_ contains the processor's and front end module's information and the datasheet. Hardware ******** The nRF52840 on the nRF21540 DK 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 nrf21540dk/nrf52840 board configuration supports the following hardware features: +-----------+------------+----------------------+ | Interface | Controller | Driver/Component | +===========+============+======================+ | ADC | on-chip | adc | +-----------+------------+----------------------+ | CLOCK | on-chip | clock_control | +-----------+------------+----------------------+ | FLASH | on-chip | flash | +-----------+------------+----------------------+ | GPIO | on-chip | gpio | +-----------+------------+----------------------+ | I2C(M) | on-chip | i2c | +-----------+------------+----------------------+ | MPU | on-chip | arch/arm | +-----------+------------+----------------------+ | NVIC | on-chip | arch/arm | +-----------+------------+----------------------+ | PWM | on-chip | pwm | +-----------+------------+----------------------+ | RADIO | on-chip | Bluetooth, | | | | ieee802154 | +-----------+------------+----------------------+ | RTC | on-chip | system clock | +-----------+------------+----------------------+ | RTT | Segger | console | +-----------+------------+----------------------+ | SPI(M/S) | on-chip | spi | +-----------+------------+----------------------+ | UART | on-chip | serial | +-----------+------------+----------------------+ | USB | on-chip | usb | +-----------+------------+----------------------+ | WDT | on-chip | watchdog | +-----------+------------+----------------------+ Other hardware features have not been enabled yet for this board. See `nRF52840 Product Specification`_ and `nRF21540 DK Hardware guide`_ for a complete list of nRF21540 Development Kit board hardware features. Connections and IOs =================== LED --- * 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 Front End Module ---------------- * MOSI = P1.13 * MISO = P1.14 * CLOCK = P1.15 * CHIP SELECT = P0.21 * PDN = P0.23 * MODE = P0.17 * RXEN = P0.19 * ANTSEL = P0.20 * TXEN = P0.22 Programming and Debugging ************************* Applications for the ``nrf21540dk/nrf52840`` board configuration can be built, flashed, and debugged in the usual way. See :ref:`build_an_application` and :ref:`application_run` for more details on building and running. Flashing ======== Follow the instructions in the :ref:`nordic_segger` page to install and configure all the necessary software. Further information can be found in :ref:`nordic_segger_flashing`. Then build and flash applications as usual (see :ref:`build_an_application` and :ref:`application_run` for more details). Here is an example for the :zephyr:code-sample:`hello_world` application. First, run your favorite terminal program to listen for output. .. code-block:: console $ minicom -D -b 115200 Replace :code:`` with the port where the board nRF21540 DK can be found. For example, under Linux, :code:`/dev/ttyACM0`. Then build and flash the application in the usual way. .. zephyr-app-commands:: :zephyr-app: samples/hello_world :board: nrf21540dk/nrf52840 :goals: build flash Debugging ========= Refer to the :ref:`nordic_segger` page to learn about debugging Nordic boards with a Segger IC. Testing the LEDs and buttons in the nRF21540 DK *********************************************** There are 2 samples that allow you to test that the buttons (switches) and LEDs on the board are working properly with Zephyr: .. code-block:: console samples/basic/blinky samples/basic/button 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 :zephyr_file:`boards/nordic/nrf21540dk/nrf21540dk_nrf52840.dts`. Changing UART1 pins ******************* The following approach can be used when an application needs to use another set of pins for UART1: 1. Add devicetree overlay file to the main directory of your application: .. code-block:: devicetree &pinctrl { uart1_default_alt: uart1_default_alt { group1 { psels = , ; }; }; /* required if CONFIG_PM_DEVICE=y */ uart1_sleep_alt: uart1_sleep_alt { group1 { psels = , ; low-power-enable; }; }; }; &uart1 { pinctrl-0 = <&uart1_default_alt>; /* if sleep state is not used, use /delete-property/ pinctrl-1; and * skip the "sleep" entry. */ pinctrl-1 = <&uart1_sleep_alt>; pinctrl-names = "default", "sleep"; }; In the overlay file above, pin P0.16 is used for RX and P0.14 is used for TX See :ref:`set-devicetree-overlays` for further details. Selecting the pins ================== Pins can be configured in the board pinctrl file. To see the available mappings, open the `nRF52840 Product Specification`_, chapter 7 'Hardware and Layout'. In the table 7.1.1 'aQFN73 ball assignments' select the pins marked 'General purpose I/O'. Note that pins marked as 'low frequency I/O only' can only be used in under-10KHz applications. They are not suitable for 115200 speed of UART. References ********** .. target-notes:: .. _nRF21540 DK Hardware guide: https://docs.nordicsemi.com/bundle/ug_nrf21540_dk/page/UG/nrf21540_DK/intro.html .. _J-Link Software and documentation pack: https://www.segger.com/jlink-software.html .. _nRF21540 website: https://www.nordicsemi.com/Products/Low-power-short-range-wireless/nRF21540 .. _nRF52840 Product Specification: https://docs.nordicsemi.com/bundle/ps_nrf52840/page/keyfeatures_html5.html .. _nRF21540 Product Specification: https://docs.nordicsemi.com/bundle/ps_nrf21540/page/keyfeatures_html5.html