[ntp:questions] problem with ntpd refclock and pps via parallel port
snews at lordynet.org
Mon Feb 1 03:30:31 UTC 2010
David Lord wrote:
> David Lord wrote:
>> problem with ntpd refclock and pps via parallel port
>> on system A I had type 22 pps working ok from pps at ttl
>> level to DCD of serial port. This was a bit erratic and
>> temperature sensitive possibly due to mismatch of ttl/rs232
>> on system B, rather than add complication of ttl=>rs232
>> conversion I've connected pps to parallel port and changed
>> symlink to be /dev/pps0 => /dev/lpt0
>> With same NetBSD-5-PPS kernel as on system A, I am getting following
>> in ntp.log at startup:
>> refclock_atom: /dev/pps0: Interrupted system call
>> configuration of 127.127.22.0 failed
>> No PPS shown by 'ntpq -p'
>> A google for above here gave some messages from suggesting
>> use of atppc* at isa?, ppbus* at atppc?, pps* at pps?
>> so now I have dmesg with
>> atppc0 at isa0 ......
>> atppc0: capabilities=3<INTR,DMA>
>> ppbus0 at atppc0
>> lpt0 at ppbus0
>> pps0 at ppbus0
>> System B, NetBSD-5, doesn't have a refclock, just other
>> ntp servers but ntp docs appear to state this as being ok.
>> On system C, NetBSD-4.0.1, which is working ntp server with
>> MSF clock on serial via DCD, I've just tried link
>> pps0 => lpt0 and have same output from ntpd as from system B.
>> I've since rewired system C with MSF to serial dsr and
>> pps to serial dcd, restarted and ntpq shows
>> SHM(0)/MSFa and PPS(0) and after a short while get +SHM(0)
>> then oPPS(0) with system having drifted > 10ms whilst
>> rewiring and restarting but now back at < 1ms.
>> So does pps really need a refclock and/or does pps via
>> parallel work ok or not on NetBSD-5?
>> Tomorrow I'll rewire gps that just about works ok out of
>> bedroom window and give that a try on system A, NetBSD-5,
>> with both serial and parallel.
> Local TV = no signal so missed film I'd intended watching
> so instead:
> GPS + nmea driver + pps0 => tty0 ok
> then after relinking to pps0 => lpt0 that's also ok.
> only difference between that and non working setup is lack
> of refclock for timecode and using one of servers on lan
> set as preferred.
> I'd intended just running ttl => lpt for pps but looks like
> I'll also need rs232 with timecode signal.
Took parallel cable back to try on the pool server and on
swapping to use lpt0 I had original error that 127.127.22.0
refclock config failed. MSFa was still listed but no PPS.
Tried again with both serial dcd and parallel NACK connected to
pps output same as by chance when using breakout adaptor
upstairs. Restarted ntpd. Now have PPS(0) again. Will it sync?
YES. Is this a bug or feature of my hardware?
Anyway 5 minutes later and "+SHM", "oPPS(0)" and offset < 1ms.
Plus jitter possibly lower with the parallel port connection,
certainly no worse from this soon after restart.
1 Feb 02:20:24 ntpd: ntpd exiting on signal 15
1 Feb 02:20:27 ntpd: clock SHM(0) event 'clk_noreply' (0x01)
1 Feb 02:20:28 ntpd: clock PPS(0) event 'clk_noreply' (0x01)
1 Feb 02:25:55 ntpd: synchronised to ........., stratum 2
1 Feb 02:25:55 ntpd: kernel time sync status change 2001
1 Feb 02:29:01 ntpd: synchronised to SHM(0), stratum 0
1 Feb 02:32:19 ntpd: synchronised to PPS(0), stratum 0
st t poll reach delay offset jitter
+SHM(0)/.MSFa. 0 l 128 377 0.000 1.414 4.028
oPPS(0) 0 l 64 377 0.000 -0.520 0.595
LOCALPEER2 2 u 256 376 0.641 -0.102 0.072
LOCALPEER3 3 u 256 376 0.385 -0.052 0.451
+PUBSERVER1 2 u 1024 77 24.038 -0.262 0.106
-PUBSERVER2 2 u 1024 77 27.644 -1.099 0.086
-PUBSERVER3 2 u 1024 77 20.870 8.630 0.279
-PUBSERVER4 2 u 1024 377 19.243 -0.799 0.238
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