[chrony-users] Chrony PPS question

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I apologize in advance if this turns out to be the wrong forum for this question.

I have a BeagleBone Black that has a Trimble C1216 chip connected to it via /dev/ttyS4 (UART4) for NMEA and /dev/pps0 (GPIO_60) BeagleBone is running debian 9.3. The proper overlays have been configured in /boot/uEnv.txt and all indications in dmesg output are that /dev/pps0 has been registered successfully. If I repeatedly run grep ocp /proc/interrupts I appear to be getting the PPS interrupts. Connecting an oscilloscope shows the pulses coming in once per second. However, when I do ppstest /dev/pps0 it indicates the following:

time_pps_fetch() error -1 (Connection timed out)

No errors in gpsd and I see that I have 9 satellites from gpsmon (gpsd 3.9 recompiled to remove PPS support). However chronyc (chrony 3.2) sources indicates a Reach value of 0 which sort of makes sense since ppstest can't get the pulse.

Exerpt from dmesg output

[   21.283132] pps pps0: new PPS source ocp:bs_pinmode_p9_12_0x27_pinm
[   21.283252] pps pps0: Registered IRQ 88 as PPS source

I'm at a loss as to why I'm not seeing the pulses on /dev/pps0. Any thoughts or suggestions?

[   21.283132] pps pps0: new PPS source ocp:bs_pinmode_p9_12_0x27_pinm


minsamples 10
refclock SHM 0 offset 0.55 delay 0.2 refid NMEA noselect
refclock PPS /dev/pps0 lock NMEA refid PPS poll 4 prefer
keyfile /etc/chrony/chrony.keys
makestep 0.1 4
driftfile /var/lib/chrony/chrony.drift
log tracking measurements statistics
logdir /var/log/chrony
maxupdateskew 100.0
dumpdir /var/lib/chrony
logchange 0.5

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