Hi
> On Feb 21, 2017, at 9:50 PM, Trevor N. <q...@comcast.net> wrote: > > On Tue, 21 Feb 2017 07:37:34 -0500, BC wrote: >> >> Some 1588 chip sets have (or had, I havent looked recently) external sync >> pins. >> This does get into the whole, whats a motherboard / whats a peripheral >> debate. Plugging in a 1588 card to get that pin probably no longer counts >> as a simple solution. If plugging in a card *does* count then that opens up >> a lot of possible options. >> >> Bob > > I found while looking at the datasheets for newer Intel server > ethernet cards that they have the ability to timestamp GPIO pin > transitions, but none of them have their internal timebase > synchronized to a counter in the CPU. It looks like they are clocked > from a separate XO on the card. Everything on a motherboard traces back to this or that XO. None of the time sources are anything that would get you excited as a frequency standard. Linking them together can be exciting. Replacing this or that one with a better frequency source *is* possible in some cases. If you are going to replace one, why not replace several :) Bob > Maybe if it was synchronized to the > PCIe clock / BCLK they could take advantage of that new Always > Running Timer in Skylake processors. I'm surprised that Intel hasn't > made a big deal about it. Support for it was added in the Linux e1000e > driver early last year. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
