> How does the pulse trigger the capture ? If some hardware line is polled, > how frequent is that polling ? The counter units may well be nanoseconds, > but the inherent uncertainty of the polling instant must be taken into > account.
> If instead there is no polling, but it is a hardware triggering, then could > you please give more details ? Thanks. The code we are talking about was originally intended to let NTP support PPS signals. The idea is that the kernel grabs a time stamp in the interrupt routine. The user can poll or wait for the next event. The details are in RFC 2783 - Pulse-Per-Second API for UNIX-like Operating Systems March 2000 http://www.faqs.org/rfcs/rfc2783.html Linux and *BSD generally support it. (For Linux, you need a recent kernel.) Details may vary. Check the source etc. It's probably an option when building the kernel and may not be turned on with the default distribution. I don't know about Windows. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ 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.