David Lord wrote:
David Lord wrote:
problem with ntpd refclock and pps via parallel port
Hi
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
levels.
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?
Gave up yesterday on desktop with pps using ppbus and pps0
from parallel port with local ntp server set as preferred.
Tried tonight on different system upstairs with pps using
ppbus from parallel port with gps nmea refclock to RxD.
NMEA showed reachable, then selected and then PPS(0) showed
reachable and eventually selected.
Removed parallel connection and it took some while for
PPS to show change in reach which then dropped from 377 over
a short period to 0. On reconnect of parallel port reach
moved back up to 377.
So at moment looks as though either refclock is essential or
some problem with parallel port on system I tried first.
David
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