I see that there are some unanswered questions in this thread.
The up-to-date answer to the original question is that AT+CCLK was added (modem firmware v1.0.x), and the time provided by the read command is based on network time if available. Not all network provide the time information, and the accuracy of the time also depend on the network. When time is not provided from the network, you must get the time by other means.
There is also the proprietary AT%CCLK command, which is similar, introduced in v1.1.x.
Regarding other methods to source time, please search other DevZone threads and create a new question for that specifically if you do not find an existing thread on the subject.
I see that there are some unanswered questions in this thread.
The up-to-date answer to the original question is that AT+CCLK was added (modem firmware v1.0.x), and the time provided by the read command is based on network time if available. Not all network provide the time information, and the accuracy of the time also depend on the network. When time is not provided from the network, you must get the time by other means.
There is also the proprietary AT%CCLK command, which is similar, introduced in v1.1.x.
Regarding other methods to source time, please search other DevZone threads and create a new question for that specifically if you do not find an existing thread on the subject.
we are using the "AT%CCLK?" at it works very nice.
but now for the challange... since the modem is synchronized with the LTE network and sends on the designated time slot, the modem knows the time in accuracy better than 1msec.
will it be possible to get a synchronization pulse once a complete second ellapses? similar to how the GPS works with PPS
that is:
1. send AT%CCLK2?
2. wait for a pulse on a hardware pin GPIO (or an internal signal)
3. get the string with [sec] resolution as we get from the "AT%CCLK?" command
Does NORDIC support something like this?
This will eliminate the need for GPS if the GPS is used only for accurate time reception
