In message <[EMAIL PROTECTED]> you write: >Udo van den Heuvel wrote: >> If the commandline at http://time.qnan.org/ for shmpps really configures >> for low-to-high (i.e.: rising edge) then why do I see -180+ ms offset >> for my Garmin GPS 18 with rising edge configured? (...) >> So what is the correct way to tell ntpd what's going on? >> Is there some peculiarity going on? >> Or am I missing something obvious?
You are using a TTL (well, CMOS) level signal to drive the RS-232 input of your serial port. The expected level conversion that should be done is thus missing. This level conversion also does a signal inversion. The only thing to care about is that one uses the correct side of the PPS pulse. The "rising edge" (as seen in the CMOS level signal) is the proper edge to trigger on. The falling edge will exhibit the "200ms offset" symptom, along with jitter. Thus, the "proper" config depends on your hardware. If you don't understand your hardware setup, you will be confused. ../Steven _______________________________________________ timekeepers mailing list [email protected] https://fortytwo.ch/mailman/cgi-bin/listinfo/timekeepers
