[time-nuts] Beaglebone NTP server

Neil Schroeder gigneil at gmail.com
Mon Dec 8 06:39:37 UTC 2014


It can be but suffers from enough jitter to be unusable.

All current BBB out of the box kernels have PPS-gpio. Google PPS gpio DTS
bbb.

Enjoy :-)

On Sunday, December 7, 2014, Chris Albertson <albertson.chris at gmail.com>
wrote:

> On Sun, Dec 7, 2014 at 12:09 PM, folkert <folkert at vanheusden.com
> <javascript:;>> wrote:
>
> >
> > On my rpi the jitter is between 2 and 10us iirc but it is a while since
> > I tested it. A quick peak shows me currently 3us jitter. Not bad for a
> > userspace solution imho.
>
>
> Really?   The PPS to GPIO interface is handles in user space?  It is not
> interrupt driven?
> In the implementations I've seen the critical real time work is done inside
> the PPS interrupt handler and then of course ntpd runs in userland and can
> take as much time as it needs
>
> --
>
> Chris Albertson
> Redondo Beach, California
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