On Sun, May 19, 2019 at 09:22:58AM -0400, Sanjay Bhandari wrote: > This seems to imply that the PPS timestamps are from the PHC. So one can > compute the offset from the GPS time, and use that to discipline the PHC > clock. > > I am a bit confused about this. Doesn't the PHC generate it's own > PPS?
Not necessarily. Not many PHCs have this capability. > Which is used when the -d option to phc2sys is used? That option is used when a PHC provides an interrupt to the kernel once a second, generating events in the Linux kernel PPS subsystem. But this won't help you unless the PHC is already synchronized to your GPS. That is problem you are trying to solve, right? > The phc2sys code seems to imply that the PPS timestamps for this are > the system clock. Is this correct? Yes, but see above. > Then what does it mean to "feed the PPS from the GPS into the PHC"? Connect a copper wire from the GPS's PPS output pin to an input pin on your PHC. HTH, Richard _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
