Re: NetBSD as an NTP stratum 1 server

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Thu, Nov 16, 2023 at 02:41:42AM -0000, joelp%sdf.org@localhost wrote:
> Hello -- Does NetBSD support PPS output from a USB GPS? I'm
> using NetBSD 10 RC1.
> 
> I have a USB GT-U7 GPS module attached, and I have gpsd running on
> /dev/ttyU0 and receiving GPS data. This looks good.
> 
> After configuring ntpd, when I run ntpshmmon, I'm seeing NTP0, but no
> NTP2. If I understand correctly, NTP2 is PPS. This seems to be confirmed
> with ntpq -p, where I don't see a PPS peer.
> 
> I unfortunately couldn't find anything when searching on this topic.
> 
> My goal is to replace an aging RPi3 with a Rock64 running NetBSD as an NTP
> stratum 1 server.

If it's a pure USB device (with no additional wriring for a PPS signal)
it won't make a good stratum-1 server. USB signals have a 1ms jitter (minimum)
so I don't think you can get a clock more precise than +-1ms with this.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--