Some boards (but not yours) have PPS-in direct timestamping. Some iMX6s have this. You’ll still need to mod the driver as it only handles PPS-out, but
it’s < 25ns accurate once running. There’s just far too much latency for PPS-in via GPIO to be useful. Richard H From: Andrey Volodin [mailto:andrevolo...@gmail.com] Sent: Mittwoch, 24. Juni 2020 16:26 Cc: linuxptp-users@lists.sourceforge.net Subject: Re: [Linuxptp-users] Fwd: Fwd: adding precision with PPS with PTP [linuxptp] on nvidia Jetson arm aarch64 device Dear Richard, Thank you for your response. How do we discipline the clocks to the global GPS time? using the software time stamping from /dev/pps0? using linuxptp scenario defined previously? How to implement a better source for PTP GM? Do you have any exact suggestions? Regards, Andrei On Wed, Jun 24, 2020 at 2:47 PM Richard Cochran <richardcoch...@gmail.com> wrote: On Wed, Jun 24, 2020 at 12:48:45PM +0000, Andrey Volodin wrote: > The initial host date/time in the example is set manually. > probably /dev/pps0 can be used at the host side to set the time/date more > accurately than using manual method defined above? so that the time > sdynchronized with the dup will come from the GPS pps timepulse [ sourced > in Ardusimple SimpleRT2K] ? So you want to discipline your two PHC clocks to the global GPS time? What are you trying to do? Remember that /dev/pps0 is using software time stamping, and as such it makes a relatively poor source for a PTP GM. Thanks, Richard
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