[time-nuts] An embedded NTP server

David J Taylor david-taylor at blueyonder.co.uk
Tue Dec 25 19:51:02 UTC 2012

Hello and Merry Christmas,

I made an embedded (S)NTP server. The software is still under
development and will eventually include a low-grade GPSDO but right now
even the simplistic algorithm is working quite well so I figured I'd share.


This is a low-level microcontroller implementation, there is no OS nor
ntpd in the traditional sense. Just enough logic to keep time using the
incoming PPS and timestamps, and a tiny VCXO to discipline. It's no
Thunderbolt and there is no clock output but it should be fantastic at
NTP. Before too long I will have adapters for connecting to Oncore
GT+/UT+ (and maybe M12, haven't checked) as well as Trimble Resolution T
and Resolution SMT using a ribbon cable instead of the jumper wires.

All open-source hardware and software. Pictures, details, and design
documents are in the eevblog thread. I'll let you all know if and when
I'm ready to sell them, for now I just wanted to show what I've got.

-- m. tharp

Fascinating, Michael, a most interesting development.  Excellent work!

I think you should be able to do better on the jitter as your algorithms 

"SNTP" does imply something else, so perhaps avoid calling it that, although 
if it doesn't respond to all the NTP management calls I'm unsure what it 
should be called!

Oh, and your Windows box is either poorly configured or broken - 
they can work much, much better than yours illustrates as I expect you know.

Merry Christmas!
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 

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