Zigbee + FreeRTOS End Device power consumption

RE: Zigbee + FreeRTOS End Device power consumption

Edvin — Mon, 05 Oct 2020 09:37:17 GMT

Hello,

Unfortunately, it doesn't look like the FreeRTOS implementation of Zigbee is power optimized, and there are no plans to do so in the nRF5 SDK.

Our zigbee team says:

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In order to suspend the task, while the timer is disabled, you have to implement ZB_COMMON_SIGNAL_CAN_SLEEP ZBOSS signal handler. Otherwise, you are simply leveraging only the ZBOSS IDLE state, not the ZBOSS SLEEP state (more information about those states can be found here: https://infocenter.nordicsemi.com/topic/sdk_tz_v4.1.0/zigbee_application_reference_component.html?cp=7_3_3_5_1#zarco_sleep).

For some guidance and ideas how to implement this, it might be good to look at the OSIF implementation in NCS:

- CAN_SLEEP handler: https://github.com/nrfconnect/sdk-nrf/blob/7a8861f03674ca0cf2f859de8ebbfebbfa0581ad/subsys/zigbee/common/zigbee_helpers.c#L455
- sleep routine (will be called by zb_sleep_now()): https://github.com/nrfconnect/sdk-nrf/blob/7a8861f03674ca0cf2f859de8ebbfebbfa0581ad/subsys/zigbee/osif/zb_nrf_pwr_mgmt.c#L30
- Poll function: https://github.com/nrfconnect/sdk-nrf/blob/7a8861f03674ca0cf2f859de8ebbfebbfa0581ad/subsys/zigbee/osif/zb_nrf_platform.c#L501

The Signal mechanism is used to wake up the ZBOSS task by other tasks that wants to send something over Zigbee, as well as to wake up the ZBOSS task earlier than the sleep period, passed to the sleep function as an argument.

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I still mean you can do quite complex things without using FreeRTOS, but I don't know what sort of device you are planning to develop.

RE: Zigbee + FreeRTOS End Device power consumption

Edvin — Tue, 29 Sep 2020 13:54:39 GMT

[quote user="sjf"]No, there is no chance to remove FreeRTOS since it is not a demo or a simple project.[/quote]

You may of course have your reasons, but I am just saying that you can do quite complex things without FreeRTOS, and possibly more effective. It is worth noticing that you can do quite a lot based on events.

However, Yes. It is the softdevice that has first priority on the radio. The Zigbee stack will ask the softdevice for timeslots in between the BLE events. The softdevice will grant timeslots to the zboss stack, so inside these the zboss stack controls the radio.

When you are using the mesh technologies in combination with BLE, the mesh technologies will have control of the radio most of the time. BLE is only used in short bursts.

I am still waiting for a reply from our Zigbee team. Stay tuned.

BR,

Edvin

RE: Zigbee + FreeRTOS End Device power consumption

sjf — Tue, 29 Sep 2020 11:40:01 GMT

Hi Edvin,

No, there is no chance to remove FreeRTOS since it is not a demo or a simple project. Radio power is automatically handled by SoftDevice?

What about Zboss stack? Was there any remarkable change from 4.0 to 4.1 about power? Is there any extra tunning in this stack to implement?

Regards,

RE: Zigbee + FreeRTOS End Device power consumption

Edvin — Tue, 29 Sep 2020 10:41:56 GMT

Can you please test either way?

Can you also see whether the current consumption is the same if you try one of the non-freertos examples? As far as I can tell, there are no changes on the FreeRTOS front between SDK 4.0.0 and 4.1.0.

Let me know if the current consumption differs a lot between the non-FreeRTOS and FreeRTOS examples. I will check with our Zigbee team if a higher current consumption is a known issue, and if there is a workaround for.

Is there a particular reason for why you need to use FreeRTOS?

BR,

Edvin

RE: Zigbee + FreeRTOS End Device power consumption

sjf — Mon, 28 Sep 2020 20:56:53 GMT

Hi Edvin,

Thanks for your response. But the increase on current consumption was ONLY after zigbee was initialized and when calling zboss_main_loop_iteration() function in the zigbee task,

Prior to that, the calling to sd_app_evt_wait() was not generating any issue like your link mentions

Regards

RE: Zigbee + FreeRTOS End Device power consumption

Edvin — Mon, 28 Sep 2020 13:54:31 GMT

Hello,

Can you please see my colleague, Susheel's, reply in this ticket:
https://devzone.nordicsemi.com/f/nordic-q-a/35073/high-power-consumption-of-softdevice

I see that this is at least not "patched" in the 4.0.0 Thread and Zigbee SDK.

Best regards,

Edvin