[time-nuts] GPS Week 1536 causing problems?

Magnus Danielson magnus at rubidium.dyndns.org
Tue Jul 7 03:13:19 UTC 2009


Hal Murray wrote:
>>>> Anyone else lose an 18x?
> 
>>> I lost one a while ago.  Similar.  It just stopped doing anything
>>> useful.
> 
>> Battery failure?
> 
> I don't think it has a battery inside.  That seems like a poor design.  Too 
> many reasonable use cases would include sitting in a drawer for extended 
> periods of time.

Providing an RTC has benefits, especially when considering week-rollover 
issues, since when the receiver wakes up it has no idea of date at all, 
pulling in the RTC time and date is a sufficient hint, and adjusting 
with detailed info from the GPS is a trivial extention. Then adjusting 
the RTC is not a hard thing to do every once in a while. The same 
problem could also be solved using EEPROM space. A byte would suffice.

Many of the GPS OEM boards I have seen has support for RTC battery. Is 
also used to keep CMOS for waypoints.

Cheers,
Magnus



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