Yo Mike! On Thu, 9 Jun 2016 20:26:01 -0400 Mike <bellyac...@gmail.com> wrote:
> >> Is seeing NTP0 twice like this typical? > > Nope, should be impossible. Looks to be exactly 500 milliSec apart. > > Do you have a square wave output? Or a 2Hz output? > > > > How about you put ppstest on it to see. Except on the Pi you only > > see one edge, so can not tell square wave from 2 Hz. Got a scope? > > What is the GPS again? > GPS module is a ST22, SkyTraq Venus 6 chipset. > > http://www.perthold.de/BINARY/gps-st22.pdf Datasheet is here. Skytraq ships varying firmware, so that is not definitive. Worse that says this: "The 1PPS pin is multiplexed with some debug mode function whose mode is to be determined at end of power on reset cycle. To avoid incorrect function do not pull-up or pull- down this signal." What could possibly go wrong there? And the serial is connected directly to a RasPi? > It's an oddball corner case I'm sure... Yes, and the Skytraq are chatty, making 9600 suspect, but unrelated to the PPS issue. > If I hook it up to a PC, or with a serial to USB adapter will I be > able to see more about the edge being seen? Depends how good you are. I leave that to you. > mike@rpi-ticker:~ $ sudo ppstest /dev/pps0 > trying PPS source "/dev/pps0" > found PPS source "/dev/pps0" > ok, found 1 source(s), now start fetching data... > source 0 - assert 1465518012.001419932, sequence: 12052 - clear > 0.000000000, sequence: 0 > source 0 - assert 1465518013.001419316, sequence: 12053 - clear > 0.000000000, sequence: 0 > source 0 - assert 1465518014.001418700, sequence: 12054 - clear > 0.000000000, sequence: 0 > source 0 - assert 1465518015.001418086, sequence: 12055 - clear > 0.000000000, sequence: 0 > source 0 - assert 1465518016.001416472, sequence: 12056 - clear > 0.000000000, sequence: 0 > source 0 - assert 1465518017.001417858, sequence: 12057 - clear > 0.000000000, sequence: 0 No double pulse there. Looks good. Hmm, it just occured to me, it is your SHM0 that is sending 2 updates a second? Was it the SHM0? If so, that is not a problem, as long as the time stamps look right, it just means the NMEA is reporting 2x a second. The only thing we care about is the SHM1. I still need the debug output. Send me the result of this: # gpsd -nND 9 /dev/ttyXX |# fgrep PPS > gpsd.log RGDS GARY --------------------------------------------------------------------------- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588
pgpREyL8Ng_Fs.pgp
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