Matter MCXW71 Lighting Example Application#

For generic information related to on/off light application, please see the common README.

Introduction#

This is an on/off lighting application implemented for an mcxw71 device.

The following board was used when testing this Matter reference app for a mcxw71 device: FRDM-MCXW71

Device UI#

The state feedback is provided through LED effects:

widget

effect

description

LED2

short flash on (50ms on/950ms off)

The device is in an unprovisioned (unpaired) state and is waiting for a commissioner to connect.

LED2

rapid even flashing (100ms period)

The device is in an unprovisioned state and a commissioner is connected via BLE.

LED2

short flash off (950ms on/50ms off)

The device is fully provisioned, but does not yet have full network (Thread) or service connectivity.

LED2

solid on

The device is fully provisioned and has full network and service connectivity.

RGB LED

on

The OnOff attribute of the On/Off cluster is true (simulating device turned on).

RGB LED

off

The OnOff attribute of the On/Off cluster is false (simulating device turned off).

NOTE: LED2 will be disabled when OTA is used. On FRDM-MCXW71 board, PTB0 is wired to both LED2 and CS (Chip Select) of the External Flash Memory. Since the OTA image is stored in external memory, LED2 operations will affect OTA operation by corrupting packages and OTA will not work.

The user actions are summarized below:

button

action

output

SW2

short press

Enable BLE advertising

SW2

long press

Initiate a factory reset (can be cancelled by pressing the button again within the factory reset timeout limit - 6 seconds by default)

SW3

short press

Toggle attribute OnOff value

SW3

long press

Clean soft reset of the device (takes into account proper Matter shutdown procedure)

The example application provides a simple UI that depicts the state of the device and offers basic user control. This UI is implemented via the general-purpose LEDs and buttons built in the MCXW71 board.

Building#

Manually building requires running the following commands:

user@ubuntu:~/Desktop/git/connectedhomeip$ cd examples/lighting-app/nxp/mcxw71
user@ubuntu:~/Desktop/git/connectedhomeip/examples/lighting-app/nxp/mcxw71$ gn gen out/debug
user@ubuntu:~/Desktop/git/connectedhomeip/examples/lighting-app/nxp/mcxw71$ ninja -C out/debug

Please note that running gn gen out/debug without --args option will use the default gn args values found in args.gni.

After a successful build, the elf and srec files are found in out/debug/. See the files prefixed with chip-mcxw71-light-example.

SMU2 Memory#

Additional memory is provided to the application by moving some Matter instances and global variables in the shared memory area from NBU domain.

Note: These instances and global variables are placed in SMU2 memory through name matching in the application linker script. They should not be changed or, if changed, the names must be updated in app.ld. See app.ld for names and SMU2 memory range size.

When compiling the application as an OT Full Thread Device (chip_openthread_ftd=true), using nxp_use_smu2_static=true gn arg will cause the following symbols to be moved to SMU2 area:

symbol name

file

gImageProcessor

OTAImageProcessorImpl.cpp

gApplicationProcessor

OTAHooks.cpp

Server::sServer

Server.cpp

ThreadStackManagerImpl::sInstance

ThreadStackManagerImpl.cpp

Additionally, using nxp_use_smu2_dynamic=true will cause the OpenThread buffers to be dynamically allocated from a 13KB SMU2 range after a successful commissioning process.

nxp_use_smu2_static and nxp_use_smu2_dynamic are set to true in the default example.

LED PWM#

In the default configuration, the onboard RGB LED pins are configured as GPIO pins. In order to enable the dimming feature, the pins need to be configured in PWM mode and synced with channels of the TPM (Timer PWM Module). To enable this feature, compile the application with: nxp_config_dimmable_led=true

If the feature is enabled, the LED brightness can be controlled using LevelControl cluster commands.

Flashing#

Two images must be written to the board: one for the host (CM33) and one for the NBU (CM3).

The image needed on the host side is the one generated in out/debug/ while the one needed on the NBU side can be found in the downloaded NXP-SDK package at path - middleware\wireless\ieee-802.15.4\bin\k32w1\k32w1_nbu_ble_15_4_dyn_matter.sb3.

Flashing the NBU image#

NBU image should be written only when a new NXP SDK is released.

  1. Install Secure Provisioning SDK tool using Python:

    pip install spsdk

    Note: There might be some dependencies that cause conflicts with already installed Python modules. However, blhost tool is still installed and can be used.

  2. Updating NBU for Wireless examples

    It is necessary to work with the matching NBU image for the SDK version of the application you are working with. This means that when you download your SDK, prior to loading any wireless SDK example, update your NBU image with the SDK provided binaries. For FRDM users, please write the following binary:

    middleware\wireless\ieee-802.15.4\bin\mcxw71\mcxw71_nbu_ble_15_4_dyn_matter_<nbu_version>.sb3

    Please note that <nbu_version> may vary depending on the SDK version.

    1. Place your device in ISP mode.

      • Make sure a jumper is placed on JP25

      • Press and hold SW4, press and release Reset, then release SW4

    2. Once the device is connected, you may find the assigned port by running:

      nxpdevscan

    3. Run the blhost command to write the sb3 file:

      blhost -p <assigned_port> receive-sb-file <path_to_SDK>\middleware\wireless\ieee-802.15.4\bin\mcxw71\mcxw71_nbu_ble_15_4_dyn_matter_<nbu_version>.sb3

Flashing the host image#

Host image is the one found under out/debug/. It should be written after each build process.

If debugging is needed then jump directly to the Debugging section. Otherwise, if only flashing is needed then JLink can be used:

  • Plug MCXW71 to the USB port (no need to keep the SW4 button pressed while doing this, e.g. ISP mode is not needed for host flashing)

  • Connect JLink to the device:

    JLinkExe -device MCXW71 -if SWD -speed 4000 -autoconnect 1

  • Run the following commands:

    reset
halt
loadfile chip-mcxw71-light-example.srec
reset
go
quit

Debugging#

One option for debugging would be to use MCUXpresso IDE.

  • Drag-and-drop the zip file containing the NXP SDK in the “Installed SDKs” tab:

Installed SDKs

  • Import any demo application from the installed SDK:

Import SDK example(s).. -> choose a demo app (demo_apps -> hello_world) -> Finish

Import demo

  • Flash the previously imported demo application on the board:

Right click on the application (from Project Explorer) -> Debug as -> JLink/CMSIS-DAP

After this step, a debug configuration specific for the MCXW71 board was created. This debug configuration will be used later on for debugging the application resulted after ot-nxp compilation.

  • Import Matter repo in MCUXpresso IDE as Makefile Project. Use none as Toolchain for Indexer Settings:

File -> Import -> C/C++ -> Existing Code as Makefile Project

New Project

  • Replace the path of the existing demo application with the path of the MCXW71 application:

Run -> Debug Configurations... -> C/C++ Application

Debug MCXW71

Running RPC console#

To build example with RPC enabled, use the following gn command: gn gen out/debug --args='import("//with_pw_rpc.gni") treat_warnings_as_errors=false'

The application runs an RPC server and processes events coming from an RPC client. An example of an RPC client is the chip-console, which can be accessed by running: chip-console --device /dev/tty.<SERIALDEVICE> -b 115200 -o pw_log.out

The console should have already been installed in the virtual environment. From the chip-console, a user can send specific commands to the device.

For button commands, please run rpcs.chip.rpc.Button.Event(index) based on the table below:

index

action

0

Start/stop BLE advertising

1

Factory reset the device

2

Application specific action (e.g. toggle LED)

3

Soft reset the device

To reboot the device, please run rpcs.chip.rpc.Device.Reboot().

OTA#

Please see mcxw71 OTA guide.