Re: 3.22 not sending PPS to SHM

[David Taylor]

On 11/01/2021 19:31, Gary E. Miller wrote:
> It means you only have one time source being sent to ntpd (or chronyd)..
> Which could be only serial time or only PPS time.
>
> RGDS
> GARY

Thanks, again, Gary.

So in the case of the Raspberry Pi, with no DCD or whatever serial PPS 
signal, the only source of PPS is the GPIO pin 18 (in my case). 
ntpshmmon shows just NTP0.  When I use servers 127.127.28.0 and 
127.127.28.1, SHM0 shows a valid non-zero offset (serial output delay), 
but SHM1 shows no connection:

pi@RasPi-22:~ $ ntpq -pn
     remote           refid      st t when poll reach   delay   offset 
 jitter
==============================================================================
x127.127.28.0    .SHM0.           0 l    6   16  377    0.000   43.709 
 0.940
 127.127.28.1    .SHM1.           0 l    -   16    0    0.000    0.000 
  0.000
o127.127.22.0    .PPS.            0 l    4   16  377    0.000    0.000 
 0.001
*192.168.0.20    .GPS.            1 u    1   32  377    1.308    0.004 
 7.783

They type 22 server shows a PPS line just as I would expect.

My expectation was that for a stand-alone Raspberry Pi I could use 28.0 
as the "time of day" ref-clock, and 28.1 as the "PPS" ref-clock.  Is it 
correct that the 28.1 ref-clock in that RPi configuration will not 
provide PPS. and I should use a combination of 28.0 and 22.0 instead? 
Or am I missing something?

Thanks,
David
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