This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.



The FRDM-KW41Z is a development kit enabled by the Kinetis® W series KW41Z/31Z/21Z (KW41Z) family built on ARM® Cortex®-M0+ processor with integrated 2.4 GHz transceiver supporting Bluetooth® Smart/Bluetooth® Low Energy (BLE) v4.2, Generic FSK, IEEE® 802.15.4 and Thread.

The FRDM-KW41Z can be used as a standalone board or as an Arduino shield. This document covers usage as a shield; see NXP FRDM-KW41Z for usage as a standalone board.

Bluetooth Controller

To use the FRDM-KW41Z as a Bluetooth low energy controller shield with a serial host controller interface (HCI):

  1. Download the MCUXpresso SDK for FRDM-KW41Z from the MCUXpresso SDK Builder Website [1].

  2. Open the MCUXpresso IDE or IAR project in boards/frdmkw41z/wireless_examples/bluetooth/hci_black_box/bm

  3. Open source/common/app_preinclude.h and add the following line:

    #define gSerialMgrRxBufSize_c 64
  4. Build the project to generate a binary hci_black_box_frdmkw41z.bin.

  5. Connect the FRDM-KW41Z board to your computer with a USB cable. A USB mass storage device should enumerate.

  6. Program the binary to flash by copying it to the USB mass storage device.

  7. Remove the USB cable to power down the board.

  8. Configure the jumpers J30 and J31 such that:

    • J30 pin 1 is attached to J31 pin 2

    • J30 pin 2 is attached to J31 pin 1

    The jumpers should be parallel to the Arduino headers. This configuration routes the UART RX and TX signals to the Arduino header, rather than to the OpenSDA circuit.

  9. Attach the FRDM-KW41Z to the Arduino header on your selected main board, such as NXP MIMXRT1050-EVK or NXP FRDM-K64F.

  10. Set -DSHIELD=frdm_kw41z when you invoke west build in your Zephyr bluetooth application. For example,

    # From the root of the zephyr repository
    west build -b frdm_k64f samples/bluetooth/peripheral_hr -- -DSHIELD=frdm_kw41z