[time-nuts] beaglebone black, debian, NTP client
attila at kinali.ch
Tue Jan 5 08:43:20 UTC 2016
On Sat, 2 Jan 2016 11:47:09 -0000
"David J Taylor" <david-taylor at blueyonder.co.uk> wrote:
> I'm also using PPS with the BBB - you even commented on my Web page!
Yes, I know. But I didn't mention your webpage, because there is something
weird going on with your system. The jitter you are seeing is very high.
And it depends on the load of the OS that seems to have many unnecessary
processes running. Even if you don't use the timer unit, like Dan Drown
did, you shouldn't see a jitter higher than 2-4us on the PPS pin (that's
approximately half the interrupt latency of the BBB including kernel/software
induced latency). But yours goes up to +/-12us, ie is 6-12 times higher.
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
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