> Is there any way for a USB device to synchronise with the CPU clock (perhaps > via the USB framing) so that a special-purpose device could timestamp the PPS > occurrence with respect to CPU time ?
If you were designing a special purpose device, just add a counter to measure the time from the PPS until the CPU reads the info. Suppose you could control the USB timing. Each sample doesn't give you a number, only a yes/no or rather a before/after. It might work if you ask a bit after you expect the PPS and the next second ask a bit before. The question is how small can you make a "bit". -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.