This application is used to create a Zigbee sleepy end device with the Silicon Labs EFR32xG21 Bluetooth Starter Kit board. It puts the device into EM2 mode for saving energy. For reaching optimization, this example disables some features like virtual VCOM, debug in EM2 mode, debug printing and so on. You can see the current consumption reduce significantly through this application.
- GSDK v4.4.0
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Silicon Labs EFR32xG21 Bluetooth Starter Kit (EFR32xG21 - BRD4180A radio board and WSTK BRD4001A mainboard).
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An external button.
The following picture shows the system view of how it works.
Note:
- btn0 and btn1 connect to PD02 and PD03 on BRD4180A, seperately. Pins on port C and port D do not have EM2/3 wake functionality. Thus, it is impossible to use btn0 on the switch to control the light, when the switch stays in EM2. Please change to another pin that connects to port A or B for such a function. For further information, please refer to the schematic of BRD4180A.
To test this application, you can either create a project based on an example project or start with a "Zigbee - SoC Switch" project based on your hardware.
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From the Launcher Home, add your hardware to My Products, click on it, and click on the EXAMPLE PROJECTS & DEMOS tab. Find the example project with the filter "sleepy switch".
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Click Create button on the Zigbee - SoC Sleepy Switch example. Example project creation dialog pops up -> click Create and Finish and Project should be generated.
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Build and flash this example to the board.
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Create a Zigbee - SoC Switch project for your hardware using Simplicity Studio 5.
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Copy all attached files in the inc and src folders into the project root folder (overwriting existing).
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Open the .slcp file. Select the SOFTWARE COMPONENTS tab and change some features in the software components:
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[Zigbee] → [Utility] → [Zigbee Device Config]: configure to Sleepy End Device as below:
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[Zigbee] → [Cluster Library] → [ZCL Framework Core]: disable Enable Command Line for Legacy CLI as below:
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[Zigbee] → [Utility] → [Debug Print]: disable some items as below:
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[Platform] → [Board] → [Board Control]: disable Enable Virtual COM UART as below:
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[Platform] → [Driver] → [Button] → [Simple Button]: uninstall btn1 instance and install btn0 instance, then configure it as below:
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[Service] → [Device Initialization] → [Peripherals] → [Energy Management Unit (EMU)]: disable Allow debugger to remain connected in EM2 as below:
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[Zigbee] → [Utility] → [Watchdog periodic refresh sample implementation]: configure refresh duration to 5000 as below:
- Build and flash the project to your device.
Note:
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Make sure to add this repository to Preferences > Simplicity Studio > External Repos.
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Do not forget to uninstall the bootloader by uninstalling Zigbee Application Bootloader component.
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There are some warnings in this project because of the disablement of some items in the Debug Print component for optimizing power consumption. We can ignore these.
For functional tests, btn0 on the switch can be used to start joining an existing network. A centralized network is required. After joining the network, btn0 can be used to send a toggle command to control the LED in the light device.
Energy Profiler is used to implement the EM2 current test. In accordance with "AEM Accuracy and Performance" section from UG172: WGM110 Wizard Gecko Module Wireless Starter Kit User's Guide, when measuring currents below 250 uA, the accuracy is 1 uA. For more precise results, it is necessary to measure the current using a high-accuracy DC analyzer.
Before current measurement, it is recommended to let the switch join a centralized network with a light, furthermore, use the command "aem calibrate" to run AEM calibration first.
When running Zigbee - SoC Switch example without any optimizations, the current of the device is approximately 12.8 mA.
The EM2 current of the switch after optimizing in the screenshot below is about 5.65 uA.
