Getting the network timestamp with CCLK doesn't work on our custom nRF9160 board

[Adam Varga]

Hello all!

Setup: nRF9160 SiP in SLM mode (mfw_nrf9160_1.3.5)

I want to get the time from the network using the AT+CCLK? or AT%CCLK? commands, and while it works perfectly on the nRF9160-DK, it doesn't work on our custom board. Other commands and functions (MQTT, HTTP, DFU download) work perfectly, so I'd think this is not a hardware issue.

If I set the time manually by CCLK="...", I can then retrieve the value by CCLK?, but I want to get the timestamp from the network.

Please see the screenshot below comparing the devboard and our board, after a cold restart. Both 91s have the exact same firmware loaded on them.

Any advice is much appreciated!

Adam

[Didrik Rokhaug]

Hi,

Are the two devices connecting to the same network?

You can check which network it is connected to with e.g. the %XMONITOR command.

Not all networks provide the time, so it might be that your custom board connects to a network that does not provide the time.

Best regards,

Didrik

[Adam Varga]

Dear Didrik,

Thanks for the tip, indeed: %XMONITOR returned different values:

Devboard:

%XMONITOR: 5,"vodafone HU","VFHU","21670","0D86",7,20,"00061901",184,6200,57,26,"","00001010","11100000","01001001"

Our board:

%XMONITOR: 5,"","","21630","2EE5",7,20,"00036702",169,6300,60,39,"","11100000","11100000","01011110"

Is there a way to force-connect to a particular carrier?

But, essentially, your note suggests to me that we should not rely on this feature, especially if our boards will be deployed internationally, using different carriers.

Do I see it correctly?

Adam

[Didrik Rokhaug]

Adam Varga said:

Is there a way to force-connect to a particular carrier?

You can use manual PLMN (network) selection with AT+COPS. However, this would stop the modem from looking for other networks. So, e.g. if the network you want to connect to don't have coverage in the area the device is, it will not look for other networks, even though it might have been able to connect to them.

We therefore generally recommend that you let the modem select the network automatically.

Adam Varga said:

But, essentially, your note suggests to me that we should not rely on this feature, especially if our boards will be deployed internationally, using different carriers.

Do I see it correctly?

Correct.

Instead of relying solely on the time (maybe) provided by the network, you can use the date_time library, which can be configured to use NTP as a backup.

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/libraries/others/date_time.html

[Adam Varga]

Thank you Didrik, your quick response is much appreciated!