NRF52840 Thread example power down 10 mins after USB disconnect

[meetandyhere]

Hello,

I am trying the Thread Cloud COAP Client

<InstallFolder>\examples\thread\experimental\cloud_coap_client

on a NRF52840 PDK. I'm using Thread SDK v0.10.0. The example works as described.

However, when I unplug the board from USB, it goes into some kind of power down mode in approx. 10 minutes and loses connection to the Thread network. I can see LED1 is still on, but it is extremely faint. It is flickering, so trying to connect to the network, but it cannot do so. After a further 5-6 minutes of this, LED1 goes completely off.

I had a few questions about this behaviour:

1. Where in the code can I set the time between USB disconnect and going in power-down mode?
2. I know that the NRF52840 has System ON and System OFF power modes. Where in the code can I set which mode it should go in?
3. Is the behaviour of it not being able to connect to the Thread network when in low power mode expected? If so, can I change this behaviour or is there a fix planned?

Thanks in advance!

Regards

Andy

[Robert Lubos]

Hi, Unforunately the observer feature is not present in OpenThread's CoAP implementation. Althought there is an API to add "Observe" option to the header, there is no mechanism to handle Observe responses from the server. And just FYI, the aObserve paramter is the value of the Observe option, For more information about this mechanism, please refer to RFC 7641. An option to use the Observe mechanism is to use different CoAP implementation, for example the IoT CoAP that we use in the DFU example (you can find it inside DFU example folder in the recent release). Unfortunately there is no Thread example that demonstrates the use of it, but you can refer to the documentation: infocenter.nordicsemi.com/.../lib_iot_coap_addon_observe.html