[LinuxPPS] can't get ntp syncing with palisade and atom drivers

[Hal V. Engel]

On Thursday 11 December 2008 07:46:02 Ian Bobbitt wrote:
> I'm using kernel 2.6.27.8 with the ntp-pps-2.6.27-rc3-bis.diff patch
> applied. I'm trying the ntp-dev-4.2.5p149 development tag of ntp.
> Does anyone know what's going wrong and how I can get it going right?
>
> I'm able to see the pps signal if I use ppstest:
>
> [root at ntp pps]# ./ppsldisc /dev/ttyS1 &
> [1] 4742
> [root at ntp pps]# ./ppstest /dev/pps0
> trying PPS source "/dev/pps0"
> found PPS source "/dev/pps0"
> ok, found 1 source(s), now start fetching data...
> source 0 - assert 1229009608.010237952, sequence: 5 - clear
> 1229009609.010162833, sequence: 6
> source 0 - assert 1229009609.010267749, sequence: 6 - clear
> 1229009609.010162833, sequence: 6
> source 0 - assert 1229009609.010267749, sequence: 6 - clear
> 1229009610.010193935, sequence: 7
> source 0 - assert 1229009610.010297382, sequence: 7 - clear
> 1229009610.010193935, sequence: 7
> source 0 - assert 1229009610.010297382, sequence: 7 - clear
> 1229009611.010223822, sequence: 8
> source 0 - assert 1229009611.010328763, sequence: 8 - clear
> 1229009611.010223822, sequence: 8
> ^C
> [root at ntp pps]#

PPS is working but there are two things I notice that are a little odd.  First 
the PPS pulse is very short at about 105 microseconds.  This may not a an 
issue with your driver.  Second on any given sequence the assert happens AFTER 
the clear.  This last one indicates to me that the PPS pulse is inverted.

>
> If I use an external server for time I can sync to the pps signal:
>
> [root at ntp ~]# ntpq -p
>       remote           refid      st t when poll reach   delay
> offset  jitter
> =
> =
> =
> =
> =
> =
> ========================================================================
> +sd-pc.indiana.g 128.10.252.6     2 u   34   64   17    1.297
> -21.022  11.006
> oPPS(0)          .PPS.            2 l    7   16    3    0.000
> -24.351   0.987
> [root at ntp ~]#
>
> ------------------8<------------------
>
> server ntp.indiana.gigapop.net prefer
>
> ## 22 is PPS "ATOM" device
> server 127.127.22.0 minpoll 4 maxpoll 6
> fudge  127.127.22.0 flag2 1 flag3 1
>
> # Palisade driver, mode 1 is praecis in trimble emul mode
> #server 127.127.29.0 mode 1 prefer
> #fudge 127.127.29.0 refid CDMA

You have mode set to 1 which would indicate that you are using an " Endrun 
Praecis in Trimble emulation mode".  This that correct?  If it is not then 
this may be your issue.

>
> enable stats
>
> driftfile /etc/ntp.drift
> statistics loopstats
> statsdir /var/log/ntp/
>
> filegen peerstats file peers type day link enable
> filegen loopstats file loops type day link enable
>
> statistics clockstats
> filegen clockstats file clock type day link enable
>
> # don't let folks modify anything
> restrict default nomodify
> # but don't restrict localhost
> restrict 127.0.0.1
> ------------------8<------------------
>
> But when I try adding the time signal from the device, I can't sync to
> pps anymore, and I get a bunch of odd messages in dmesg (I have
> debugging on):
>
> ------------------8<------------------
> [IRQev] PPS clear at 266451 on source #0
> PPS event on source 0 at 1229010139.28085655
> capture assert seq #536 for source 0
> [IRQev] PPS assert at 266451 on source #0
> PPS event on source 0 at 1229010140.28021410
> capture clear seq #537 for source 0
> [IRQev] PPS clear at 266551 on source #0
> PPS event on source 0 at 1229010140.28125295
> capture assert seq #537 for source 0
> [IRQev] PPS assert at 266551 on source #0
> PPS_GETCAP: source 0
> PPS_SETPARAMS: source 0
> PPS_GETPARAMS: source 0
> PPS_GETCAP: source 0
> PPS_SETPARAMS: source 0
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> timeout 0.000000000
> PPS_FETCH: source 0
> ------------------8<------------------
>
> [root at ntp ~]# ntpq -p
>       remote           refid      st t when poll reach   delay
> offset  jitter
> =
> =
> =
> =
> =
> =
> ========================================================================
>   sd-pc.indiana.g 128.10.252.6     2 u   24   64    3    1.328
> -25.967   0.103
>   PPS(0)          .PPS.            0 l    -   16    0    0.000
> 0.000   0.000
> *GPS_PALISADE(0) .CDMA.           0 l    7   16   37    0.000
> -28.031   1.026
> [root at ntp ~]#
>
>
>
>
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