I'm developing a Python 3 app on a Raspberry Pi running Wheezy (Debian
7.8). I need help selecting the right version of Chrony to use and
configuring PPS. My GPS is an Adafruit Ultimate GPS Hat using ttyAMA0
with PPS on GPIO pin 4. My app is a mobile one. It may have internet
access via
Rob,
Thanks for replying.
A little more info: my system is a Raspberry Pi 2 B. I have been able
to get ntp to work with pps via GPIO pin 4. Had to recompile ntp to
activate the pps support.
Don't let the above fool you into thinking I know what I am doing. I
have some level of expertise
On 18/02/2016 22:48, Deven Hickingbotham wrote:
$cat /sys/class/pps/pps0/assert
1455831692.018636856#178
Are you seeing those?
Yes, but just one timestamp per execution:
pi@gps ~ $ cat /sys/class/pps/pps0/assert
1455835119.289108505#4272
pi@gps ~ $ cat /sys/class/pps/pps0/assert
Bryan,
I changed chrony.conf to include:
refclock SHM 0 precision 1e-1 offset -0.135 delay 0.5 refid NEMA
refclock SHM 1 offset 0.00135 delay 0.1 refid PPS
refclock SOCK /var/run/chrony.ttyAMA0.sock offset 0.00135 delay 0.0
refid SOCK
Now 10 minutes after restarting chronyc sources outputs:
On Thu, 18 Feb 2016, Deven Hickingbotham wrote:
On 2/18/2016 4:12 PM, Bryan Christianson wrote:
OK _ are you stopping gpsd, restarting chronyd then restarting gpsd? Order
matters (well it used to anyway)
Yes, I did that. No change in the chronyc sources output. GPS apps like
cgps -s work.
First off, thanks for all of the responses! I'm testing your
suggestions as fast as I can and if I apologize if I don't directly
reply to a suggestion.
Does /var/run/chrony.ttyAMA0.sock exist? If not, then it is hard to read
from
it. Your gpsd does not seem to be writing to SHM0
Yes, it
William G. Unruh | Canadian Institute for| Tel: +1(604)822-3273
Physics | Advanced Research | Fax: +1(604)822-5324
UBC, Vancouver,BC | Program in Cosmology | un...@physics.ubc.ca
Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/
On Thu, 18 Feb
William G. Unruh | Canadian Institute for| Tel: +1(604)822-3273
Physics | Advanced Research | Fax: +1(604)822-5324
UBC, Vancouver,BC | Program in Cosmology | un...@physics.ubc.ca
Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/
On Thu, 18 Feb
Tom,
refclock SHM 0 refid GPS precision 1e-1 offset 0. delay 0.2 noselect
refclock SOCK /var/run/chrony.ttyAMA0.sock refid PPS lock GPS
I made the above changes, restarted chrony, waited 10 minutes and:
pi@gps ~/SystemFiles $ chronyc sources
210 Number of sources = 6
MS Name/IP address
William G. Unruh | Canadian Institute for| Tel: +1(604)822-3273
Physics | Advanced Research | Fax: +1(604)822-5324
UBC, Vancouver,BC | Program in Cosmology | un...@physics.ubc.ca
Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/
On Thu, 18 Feb
Bill,
On 2/18/2016 4:06 PM, Bill Unruh wrote:
pi@gps ~ $ cat /sys/class/pps/pps0/assert
1455835119.289108505#4272
Yes, as should be, assuming that it was about 33 sec between the one
above and
below, and then about 3 sec. However I am worried that you are getting
such differences in ms. What
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