Updating RTC at every 24hours

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Hi all,

 

I have a project I am using RTC and GSM interfaced. I need to update RTC time by getting GSM time at every 24hour (Say at 12AM). In the sense when date changes I have to update my RTC Time.

 

What method can I use?

 

I am using Atmega164A, GSM900A,

 

Please help me in this.

 

 

Thank you In advance.

Last Edited: Fri. Apr 21, 2017 - 03:35 PM
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SNAP!

 

My Google was "get network time using sim900" and that thread was the top hit for that too :-)

 

The same search hit a load of useful looking threads. A brief summary is given in this:

 

https://importgeek.wordpress.com...

 

So the bottom line of it all:

AT+CCLK?

 

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I would suggest sync'ing your time shortly after 2 am, that way you will also automagicly adjust for standard/daylight savings as well as correcting for any clock drift.

Jim

 

 

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clawson wrote:
So the bottom line of it all:

AT+CCLK?

Not sure I trust that.

 

AT+CCLK is a GSM 07.07 Standard command: it usually relates to the module's local RTC - not the Network time.

 

The Blog refers to using AT+CENG to turn on "Engineering Mode". The SIM900_AT Command Manual_V1.11.pdf says nothing to indicate that this sets the RTC

 

http://simcom.ee/documents/?dir=...

 

 

But one thing is certain: it has nothing specifically to do with AVR.

Last Edited: Fri. Apr 21, 2017 - 03:23 PM