[ntp:questions] Time syncing with something other than ntpd

Jakob Bohm jb-usenet at wisemo.com
Fri Feb 3 19:17:30 UTC 2017


On 01/02/2017 12:56, David Taylor wrote:
> On 01/02/2017 10:59, Jakob Bohm wrote:
> []
>> As I am looking at the BBB myself, here are some extra questions:
>>
>> 1. Do you know if anyone has tried using the real-time coprocessors on
>>   the BBB to more accurately track the PPS signal?
>>
>> 2. I presume the BBB could be put in a shielded case (I see some
>>   offered online).  Any experience with that?
>>
>> Enjoy
>> Jakob
>
> Jakob,
>
> (1) No.  Do you mean using the counters to record the timing of the PPS
> more precisely?
>

No, I was thinking about the two "PRU" 200MHz low latency I/O
controllers on the chip, one of those could be made to run its own
little timing PLL loop directly watching the PPS GPIO pin, then
allowing the ARM CPU (running NTPD) to check the high resolution delta
between its own (NTP/Linux) time and the PPS synced loop.


> (2) No, but without the BBB radiates more interference than the RPi.
>


Enjoy

Jakob
-- 
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
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