NTP Date/Time from nrfConnect v1.2.1

[dave_s]

For reasons beyond my control I need to do some changes to a nrf9160 project that was developed using nrfConnect v1.2.1.  I know the ideal situation is to upgrade it to the latest version, but it uses several deprecated config options that would require a lot of testing if I had to change.

I need to get the current time.. I thought I could easily do with the Date/Time module, but it looks like it isn't supported in v1.2.1.  Is there a way in that version to get the current time?  Or configure the modem to update the time as needed and then read the time from that?

[Håkon Alseth]

Hi,

 

Although I would recommend that you upgrade your project, you could cherry-pick the initial commit for the date_time library:

https://github.com/nrfconnect/sdk-nrf/commit/1e6e3e3530be53f5a61794fbc30c6c7f58f6f4d3

 

The current time can also be queried via AT%XTIME (if your connected network provides time):

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/xtime_set.html?cp=2_2_0_7_8_0

See this function for how to translate it: https://github.com/nrfconnect/sdk-nrf/blob/v2.6.0/lib/date_time/date_time_modem.c#L109

 

Kind regards,

Håkon

[dave_s]

Hi,

I changed my approach to get the time from the modem using modem_info_string_get with MODEM_INFO_DATE_TIME

Here is the response I get

24/04/19,18:50:33-20dy

What is the '-20dy' portion represent?

Is there way to retrieve the modem time in seconds since epoch?  Or do I need to parse the string to get the UTC date/time?

Is the format and string length always the same regardless of the date / time?

How / when does the modem time get updated?  Is there a way to know how recently updated it is?

[Håkon Alseth]

Hi,

 

The specific modem_info call will effectively call AT+CCLK, which should return a string similar to this:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fref_at_commands%2FREF%2Fat_commands%2Fnw_service%2Fxtime_set.html&cp=2_2_0_7_8_0

 

Q1: What modem fw version are you using?

Q2: How are you implementing the routine to fetch MODEM_INFO_DATE_TIME? Can you share this?

dave_s said:

Is there way to retrieve the modem time in seconds since epoch?  Or do I need to parse the string to get the UTC date/time?

You will need to add a routine for it, similar to this:

https://github.com/nrfconnect/sdk-nrf/blob/v2.6.0/lib/date_time/date_time_modem.c#L109

dave_s said:

Is the format and string length always the same regardless of the date / time?

string length returned is \0 terminated, length will vary

dave_s said:

How / when does the modem time get updated?  Is there a way to know how recently updated it is?

If the network supports and provides time, it is sent as a part of the EPS MM (EMM) PDU, as described here:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/xtime_set.html?cp=2_2_0_7_8_0

 

Kind regards,

Håkon

[dave_s]

Q1: What modem fw version are you using? mfw_nrf9160_1.1.2
Q2: How are you implementing the routine to fetch MODEM_INFO_DATE_TIME? Can you share this?  

    char sbuf[30];

    size = modem_info_string_get(MODEM_INFO_DATE_TIME, sbuf);

The string being returned is like this

24/04/22,15:18:34-20

which doesn't seem to match a standard format

[Håkon Alseth]

Hi,

 

That is the format of CCLK:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/cclkl_set.html?cp=2_2_0_4_22_0

 

You can use scanf to convert it into struct tm:

https://github.com/nrfconnect/sdk-nrf/blob/v2.6.0/lib/date_time/date_time_modem.c#L53-L65

 

Kind regards,

Håkon