Re: [chrony-users] Chrony setup on Raspberry Pi with GPS PPS

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> On 7/10/2015, at 4:07 AM, Deven Hickingbotham <devenh@xxxxxxxxxxx> wrote:
> I'm looking for guidance on installing Chrony on a Raspberry Pi running Raspbian.  I have the Ultimate GPS Hat installed that provides PPS on pin 4.  I will have only intermittent internet connections, so the PPS should be the primary time source.  I want the time adjustment/correction to be immediate after boot up.  I don't want a smooth/gradual correction.

I have a raspberry-pi running both gpsd and chronyd and its working very well in an offline mode.

> Couple of newbie questions (in addition to any general guidance):
> 1. Does Chrony replace NTP?  I assume so, but I haven't found this explicitly stated.  If so, instructions on how to disable NTP autostart and enabling Chrony autostart would be helpful.

Yes = chrony replaces ntpd

> 2. Does PPS support require any special instructions when compiling Chrony?  I've seen references to timepps.h.  Is this file included with the Chrony source?  If not, where can it be found?
> 3. Examples of chrony.conf with PPS support?
> 4. After installation, what commands can be run to confirm that PPS is enabled?

I suggest you take a look at the gpsd documentation. This explains how you can use the gpsd daemon to feed PPS data to chrony

To make life simple I suggest your initial approach should be to use the debian (raspbian) packages, which will install the required startup scripts for both daemons

aptitude install gpsd

Get your configuration working with gpsd first. The documentation is good so that shouldn't be too much of a problem. The mail list (for gpsd) is also your friend if you run into problems

aptitude install chrony
Configure chrony as described in the gpsd docs

When you have it all running with the raspbian distributed software, then look at compiling/configuring more recent versions of both gpsd and chrony

Hope that helps
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