[time-nuts] Lowest Power NTP Server

Tim Shoppa tshoppa at gmail.com
Sun Dec 1 22:42:46 UTC 2019


Didier, I'm not sure I saw Bob write that 5uS was his goal.

I don't think anyone would claim that ordinary cheap WiFi can achieve
consistent sub-millisecond variations in latency.

Tim N3QE

On Sun, Dec 1, 2019 at 5:06 PM Didier Juges <shalimr9 at gmail.com> wrote:

> You should look at latency. The ESP8266 has serial (SPI) flash and a
> relatively small internal cache. When the chip needs to load code from
> flash, that can take a while, compared to the 5uS target. Great for cheap
> IoT stuff, not so great for time sensitive, in my opinion.
>
> On Sun, Dec 1, 2019 at 2:01 PM David <david at mju.io> wrote:
>
> > I'd think one of the ESP32's would be a fine choice. They have some good
> > power management options to wake up periodically to do the work, making
> for
> > even lower power consumption.
> >
> > Looks like someone has already written some code that could be adapted?
> >
> > https://github.com/DennisSc/PPS-ntp-server/blob/master/README.md
> >
> > -David
> >
> > -------- Original Message --------
> > On Dec 1, 2019, 09:49, Bob kb8tq wrote:
> >
> > > Hi
> > >
> > > So something like one of the many ESP32 based boards?
> > >
> > > Of course when it comes to the “code from scratch” part there is the
> > problem that I’m
> > > pretty (most would say very …) lazy :) :) :)
> > >
> > > Bob
> > >
> > >> On Dec 1, 2019, at 12:29 PM, Poul-Henning Kamp <phk at phk.freebsd.dk>
> > wrote:
> > >>
> > >> --------
> > >>
> > >> You can do better than RPi, since a NTP server basically
> > >> only needs to understand two packets: IP/UDP at port 123
> > >> and ARP packets.
> > >>
> > >> There are WiFi enabled microcontrollers that could be taught how
> > >> to do that, but you'd have to write up your NTP daemon from scratch
> > >> which is not hard when you do not have to do the "sync clock from
> > >> remote servers" part.
> > >>
> > >>
> > >> --
> > >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
> > >> phk at FreeBSD.ORG | TCP/IP since RFC 956
> > >> FreeBSD committer | BSD since 4.3-tahoe
> > >> Never attribute to malice what can adequately be explained by
> > incompetence.
> > >
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