Rasp Pi at +/- 1 us from GPS

Hal Murray hmurray at megapathdsl.net
Mon Nov 27 02:43:55 UTC 2017

devel at ntpsec.org said:
>> You don't need the RTC.  You can get the initial time over the net.

> But the time I can get from the DS3231 RTC after outages should have
> drifted in microseconds, or tens of or hundreds of. So very fast sync to
> TOS by pps-client once booted and GPS solution provided. ...  

I wasn't trying to discourage you from playing with the RTC, just pointing 
out that it isn't necessary in case somebody else wants to do something 

Actually, my comment about the network was misleading.  You already have GPS. 
 You can't deliver serious time until the GPS has started tracking satellites 
and such, and that gives you time.

It's actually tricky to get good time from most RTC chips.  You can easily 
read to a second, but you have to work harder to get better than a second, 
either by polling and watching for the seconds to change, or something like 
an interrupt on a second change.

These are my opinions.  I hate spam.

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