The Project CHIP K32W061 Lock Example demonstrates how to remotely control a door lock device with one basic bolt. It uses buttons to test changing the lock and device states and LEDs to show the state of these changes. You can use this example as a reference for creating your own application.
The example is based on Project CHIP and the NXP K32W SDK, and supports remote access and control of a simulated door lock over a low-power, 802.15.4 Thread network.
The example behaves as a Project CHIP accessory, that is a device that can be paired into an existing Project CHIP network and can be controlled by this network.
The K32W061 lock example application provides a working demonstration of a connected door lock device, built using the Project CHIP codebase and the NXP K32W061 SDK. The example supports remote access (e.g.: using CHIP Tool from a mobile phone) and control of a simulated door lock over a low-power, 802.15.4 Thread network. It is capable of being paired into an existing Project CHIP network along with other Project CHIP-enabled devices.
The example targets the NXP K32W061 DK6 development kit, but is readily adaptable to other K32W-based hardware.
The CHIP device that runs the lock application is controlled by the CHIP controller device over the Thread protocol. By default, the CHIP device has Thread disabled, and it should be paired over Bluetooth LE with the CHIP controller and obtain configuration from it. The actions required before establishing full communication are described below.
The example also comes with a test mode, which allows to start Thread with the default settings by pressing a button. However, this mode does not guarantee that the device will be able to communicate with the CHIP controller and other devices.
Deployment of this firmware configuration requires the K32W061 board setups using the K32W061 module board, SE051 Expansion board and Generic Expansion board as shown below:
The SE051H Secure Element extension may be used for best in class security and offloading some of the Project CHIP cryptographic operations. Depending on your hardware configuration, choose one of the options below (building with or without Secure Element). NOTE: the SE051H is a derivative of the SE051 product family (see http://www.nxp.com/SE051) including dedicated CHIP support in addition to the SE051 feature set. See the material provided separately by NXP for more details on SE051H.
In this example, to commission the device onto a Project CHIP network, it must be discoverable over Bluetooth LE. For security reasons, you must start Bluetooth LE advertising manually after powering up the device by pressing Button USERINTERFACE.
In this example, the commissioning procedure (called rendezvous) is done over Bluetooth LE between a CHIP device and the CHIP controller, where the controller has the commissioner role.
To start the rendezvous, the controller must get the commissioning information from the CHIP device. The data payload is encoded within a QR code, printed to the UART console and shared using an NFC tag. For security reasons, you must start NFC tag emulation manually after powering up the device by pressing Button 4.
Last part of the rendezvous procedure, the provisioning operation involves sending the Thread network credentials from the CHIP controller to the CHIP device. As a result, device is able to join the Thread network and communicate with other Thread devices in the network.
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 to the OM15082 Expansion board attached to the DK6 board.
LED D2 shows the overall state of the device and its connectivity. Four states are depicted:
LED D3 shows the state of the simulated lock bolt. When the LED is lit the bolt is extended (i.e. door locked); when not lit, the bolt is retracted (door unlocked). The LED will flash whenever the simulated bolt is in motion from one position to another.
Button SW2 can be used to reset the device to a default state. A short Press Button SW2 initiates a factory reset. After an initial period of 3 seconds, LED2 D2 and D3 will flash in unison to signal the pending reset. After 6 seconds will cause the device to reset its persistent configuration and initiate a reboot. The reset action can be cancelled by press SW2 button at any point before the 6 second limit.
Button SW3 can be used to change the state of the simulated bolt. This can be used to mimic a user manually operating the lock. The button behaves as a toggle, swapping the state every time it is pressed.
Button SW4 can be used for joining a predefined Thread network advertised by a Border Router. Default parameters for a Thread network are hard-coded and are being used if this button is pressed.
The remaining two LEDs (D1/D4) and button (SW1) are unused.
Directly on the development board, Button USERINTERFACE can be used for enabling Bluetooth LE advertising for a predefined period of time. Also, pushing this button starts the NFC emulation by writing the onboarding information in the NTAG.
In case the OM15082 Expansion board is not attached to the DK6 board, the functionality of LED D2 and LED D3 is taken over by LED DS2, respectively LED DS3, which can be found on the DK6 board.
Also, by long pressing the USERINTERFACE button, the factory reset action will be initiated.
In order to build the Project CHIP example, we recommend using a Linux distribution (the demo-application was compiled on Ubuntu 20.04).
Download K32W061 SDK 2.6.4 for Project CHIP. Creating an nxp.com account is required before being able to download the SDK. Once the account is created, login and follow the steps for downloading SDK_2_6_4_K32W061DK6. The SDK Builder UI selection should be similar with the one from the image below. 
Start building the application either with Secure Element or without
user@ubuntu:~/Desktop/git/connectedhomeip$ export NXP_K32W061_SDK_ROOT=/home/user/Desktop/SDK_2_6_4_K32W061DK6/
user@ubuntu:~/Desktop/git/connectedhomeip$ ./third_party/nxp/k32w0_sdk/sdk_fixes/patch_k32w_sdk.sh
user@ubuntu:~/Desktop/git/connectedhomeip$ source ./scripts/activate.sh
user@ubuntu:~/Desktop/git/connectedhomeip$ cd examples/lock-app/nxp/k32w/k32w0/
user@ubuntu:~/Desktop/git/connectedhomeip/examples/lock-app/nxp/k32w/k32w0$ gn gen out/debug --args="k32w0_sdk_root=\"${NXP_K32W061_SDK_ROOT}\" chip_with_OM15082=1 chip_with_ot_cli=0 is_debug=false chip_crypto=\"mbedtls\" chip_with_se05x=0"
user@ubuntu:~/Desktop/git/connectedhomeip/examples/lock-app/nxp/k32w/k32w0$ ninja -C out/debug
user@ubuntu:~/Desktop/git/connectedhomeip/examples/lock-app/nxp/k32w/k32w0$ $NXP_K32W061_SDK_ROOT/tools/imagetool/sign_images.sh out/debug/
- with Secure element
Exactly the same steps as above but set chip_with_se05x=1 in the gn command
and add arguments chip_pw_tokenizer_logging=true chip_enable_ota_requestor=false
Note that options chip_pw_tokenizer_logging=true and chip_enable_ota_requestor=false are required for building with Secure Element. These can be changed if building without Secure Element
Note that “patch_k32w_sdk.sh” script must be run for patching the K32W061 SDK 2.6.4.
Also, in case the OM15082 Expansion Board is not attached to the DK6 board, the build argument (chip_with_OM15082) inside the gn build instruction should be set to zero. The argument chip_with_OM15082 is set to zero by default.
In case that Openthread CLI is needed, chip_with_ot_cli build argument must be set to 1.
In case signing errors are encountered when running the “sign_images.sh” script install the recommanded packages (python version > 3, pip3, pycrypto, pycryptodome):
user@ubuntu:~$ python3 --version Python 3.8.2 user@ubuntu:~$ pip3 --version pip 20.0.2 from /usr/lib/python3/dist-packages/pip (python 3.8) user@ubuntu:~$ pip3 list | grep -i pycrypto pycrypto 2.6.1 pycryptodome 3.9.8
The resulting output file can be found in out/debug/chip-k32w061-lock-example.
Program the firmware using the official OpenThread Flash Instructions.
All you have to do is to replace the Openthread binaries from the above documentation with out/debug/chip-k32w061-lock-example.bin if DK6Programmer is used or with out/debug/chip-k32w061-lock-example if MCUXpresso is used.
The example also offers the possibility to run in low power mode. This means that the board will go in a deep power down mode most of the time and the power consumption will be very low.
In order build with low power support, the chip_with_low_power=1 must be provided to the build system. In this case, please note that the GN build arguments chipwith_OM15082 and _chip_with_ot_cli must be set to 0.
In order to maintain a low power consumption, the LEDs showing the state of the elock and the internal state are disabled. Console logs can be used instead. Also, please note that once the board is flashed with MCUXpresso the debugger disconnects because the board enters low power.
Power Measurement Tool can be used inside MCUXpresso for checking the power consumption pattern: Window -> Show View -> Other -> Power Measurement Tool. The configuration for this tool is the next one:
Also, please make sure that the J14 jumper is set to the ENABLED position and no expansion board is attached to the DK6. A view from this tool is illustrated below:
Please note that that the Power Measurement Tool is not very accurate and professional tools must be used if exact power consumption needs to be known.
The app can be deployed against any generic OpenThread Border Router. See the guide Commissioning NXP K32W using Android CHIPTool for step-by-step instructions.
See Unlocking the Future of Project CHIP Webinar for an in-depth analysis of NXP capabilities for Project CHIP.