This post provides guidance on how to update the NBU firmware on MCX W72 and KW47 devices through several methods available: Bootloader Host Application (blhost), Secure Provisioning Tool, LinkServer.
The Narrow Band Unit (NBU) is a dedicated compute subsystem for the Narrowband Radio, present in select NXP wireless microcontrollers. It is comprised of an Arm® Cortex®-M33 and associated peripherals that, in conjunction with the Bluetooth Unit, support the Bluetooth LE protocol. Running at 96 MHz alongside a 2.4 GHz transceiver, the NBU operates independently from the main application core, offloading all radio processing from the primary CPU and freeing it for application tasks. While the NBU allows for flexibility for evolving requirements, firmware to implement radio protocols is intended to be developed and delivered by NXP.
Note: It is important that the NBU firmware version matches the SDK version of the application. After downloading the SDK and before running any wireless examples, update the NBU firmware using the binaries provided in the SDK folder.
The NBU binary file is located in the SDK folder. Go to the SDK root folder and open the path: \main\mcuxsdk\mcuxsdk\middleware\wireless\ble_controller\bin
To follow this guide, the following environment is required:
Software Setup
- Bootloader Host Application (blhost). Download here.
- MCUXpresso Secure Provisioning Tool. Download here.
- LinkServer for Microcontrollers. Download here.
Hardware Setup
Development boards associated with the MCX W72 or KW47 microcontroller families may be used. The ISP button varies by board and is referred to as ISP_button throughout this guide:
| Development board | ISP_button |
| FRDM-MCXW72 | SW3 |
| MCXW72-LOC | SW4 |
| KW47-EVK | SW4 |
| KW47-LOC | SW4 |
To set the board to the Bootloader ISP mode, press and hold the ISP_button, connect the development board via the MCU-Link connector to the PC, then release ISP_button.
Bootloader Host Application (blhost)
- Place the board in ISP mode by pressing and holding
ISP_button. Connect the USB cable to the MCU-Link connector and releaseISP_buttonafter the connection is established. - Verify the COM port assigned to the board by opening Device Manager in Windows and searching for Ports (COM & LPT). Identify and note the corresponding COM port number.
- Open a command prompt and change the directory to the location of the blhost.exe file:
(BLHost_root_location)\blhost_2.6.7\bin\win - Verify communication by running the following command, making sure to replace COMX with the COM port assigned to your device:
blhost.exe -p COMX get-property 1 - Update the NBU firmware image. First, erase the NBU memory:
blhost.exe -p COMX flash-erase-all 2 - Write the new firmware image using the following command. The write-memory command uses
0x48800000as the start address, which corresponds to the NBU memory base. Provide the full path to the binary file, or alternatively, copy the .bin file into the same directory as blhost.exe to simplify the command:blhost.exe -p COMX write-memory 0x48800000.bin
MCUXpresso Secure Provisioning Tool
- Create a workspace for the device. To use the keys same as the development board, select the processor relevant to the FRDM/EVK board.
- Place the board in ISP mode by pressing and holding
ISP_button. Connect the USB cable to the MCU-Link connector and releaseISP_buttonafter the connection is established.
To verify communication, click the UART tab, refresh the Port field selection and select the assigned COM Port identified. Click Test connection and confirm that the result displays OK. - In the toolbar, select the boot type as Plain unsigned or Plain with CRC.
- In the Build Image view, load the binary file in Source executable image, enter the start address as
0x48800000(which corresponds to the NBU memory base), and click Build image. - Navigate to the Write Image view, select Use built image, and click Write image.
A success message appears when the NBU firmware loading is complete.
LinkFlash Tool
For this method, a LinkServer debug probe must be available on the board. The steps on how to install the CMSIS-DAP/SEGGER J-link firmware are available here.
- Navigate to the main LinkServer folder in your computer and execute the
LinkFlash.exefile. - Place the board in ISP mode by pressing and holding
ISP_button. Connect the USB cable to the MCU-Link connector and releaseISP_buttonafter the connection is established. - In the LinkFlash tool, after the device is connected, click the Refresh button to update and set the probe target of the board.
- Go to the Program tab, click Browse, select the NBU firmware file, and enter the start address
0x48800000. - Ensure to check the boxes Mass erase before programming and Reset target after programming.
- To load the NBU firmware, click Program.
