Can't get GPS/PPS to work

Philipp Ammann philipp.ammann at
Fri May 20 10:55:20 UTC 2022

Hi Hal,

Am 19.05.22 um 03:34 schrieb Hal Murray:
> I don't see anything obviously wrong.
> If I was chasing this, I would turn on clockstats.  You may want to remove the 
> minpoll/maxpoll, to reduce logging clutter.  That will also simplify things 
> slightly.
> clockstats will give you a line of counters every polling interval.  I forget 
> what they mean, but the details are in the documentation.  (and/or code)
> On Linux, you can sanity check the PPS with:
>   cat /sys/devices/virtual/pps/pps0/assert
>   cat /sys/devices/virtual/pps/pps0/clear
> One should count, the other should be stopped (ntpd turns it off).

Thank you for the hint. Will try that if I need further debugging :)

> Does the uBlox Neo-7M default to 9600 baud and NMEA?

The Neo-7M supports only 9600 Baud.

> Is ttyAMA0 tangled up with Bluetooth on the Pi 4?  (I forget how to kill Bluetooth.)

Bluetooth is disabled using "dtoverlay=disable-bt" in config.txt. AMA
seems to be an ARM-specific name for a serial port.



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