Very true. If your exchanging data for loose timing purposes (wall clock) over a UART whether it is binary coded or ASCII coded is immaterial. You will always introduce at least 1/16 of a bit time of jitter, if not one full bit time, allowing the uart to sync to start bit edge.
In full honesty I have never read the official NMEA-0183 specification. Just a sample from an unoffical NMEA0183.pdf <http://www.tronico.fi/OH6NT/docs/NMEA0183.pdf> *ZDA Time & Date – UTC, Day, Month, Year and Local Time Zone* *$--ZDA,hhmmss.ss,xx,xx,xxxx,xx,xx*hh* So for a GPS or a timing unit on a NMEA-0183 bus, do they report their best estimate of time to the nearest 10ms when the packet is sent? (since a PPS line isn't shared) On Tue, Jul 19, 2016 at 1:17 PM, Chris Albertson <albertson.ch...@gmail.com> wrote: > On Mon, Jul 18, 2016 at 10:44 AM, Scott Stobbe <scott.j.sto...@gmail.com> > wrote: > > I am happy to hear you issue was resolved. What I meant to say is the > > problem could also be mitigated using the UART's flow control, this could > > be done by the original GPS designers or by an end user if the CTS line > is > > pined out. > > The original GPS designers where sending NMEA-0183 data out to devices > that accept and use NMEA data. GPS was not the first to work with > NMEA. Lots of other instruments also output NMEA. I doubt they ever > would have envisioned people using NMEA data for precision timing. > Typically if you want to do precision timing you's use a GPS that > outputs some binary data format. NMEA-0183 does not have flow control > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > 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.