[ntp:questions] pps breaks when nmea is enabled for ntpd
Richard Cagley
rcagley at gmail.com
Sun Jun 16 00:54:49 UTC 2013
Very interesting. So, you just have this as your ntp.conf file?
server 127.127.20.1 mode 0 minpoll 4 maxpoll 4 prefer
fudge 127.127.20.1 flag1 1 flag3 1 refid PPS
When I do this I think only the GPS/127.127.20.0 line shows up in the
output. How do I know PPS is working? With just these two lines in my
ntp.conf file should I expect two lines in the output of ntpq -p?
I'll have to confirm this when I get co-located with the hardware tomorrow.
On Sat, Jun 15, 2013 at 10:10 AM, David Taylor <
david-taylor at blueyonder.co.uk.invalid> wrote:
> On 15/06/2013 02:03, Richard Cagley wrote:
>
>> I have a TI DM8168 processor and a u-blox gps.
>>
>> If I enable an internet server and pps, then pps works great
>>
>> server clock.redhat.com iburst prefer minpoll 4 maxpoll 4
>> server 127.127.22.0 minpoll 4 maxpoll 4
>> fudge 127.127.22.0 flag3 1
>>
>> However, if I add an NMEA server to my ntp.conf file like this
>>
>> server 127.127.20.0 mode 1
>> fudge 127.127.20.0 flag1 1
>> server 127.127.22.0 minpoll 4 maxpoll 4
>> fudge 127.127.22.0 flag3 1
>>
>> then pps stops working. I can kill ntpd and ppstest no longer works. It's
>> as though nmea is clobbering the serial port.
>>
>> It sorta feels like this, but there was no resolution
>> http://lists.ntp.org/**pipermail/questions/2011-**September/030347.html<http://lists.ntp.org/pipermail/questions/2011-September/030347.html>
>>
>> Can anyone help me. I've really been struggling with this.
>>
>
> On my FreeBSD system, to enable PPS on the type 20 (NMEA) driver, I just
> added flag1 and flag3 set to 1:
>
> ______________________________**___________
> server 127.127.20.1 mode 0 minpoll 4 maxpoll 4 prefer
> fudge 127.127.20.1 flag1 1 flag3 1 refid PPS
> ______________________________**___________
>
> It's running ntpd 4.2.7p368, and does have Internet servers as well.
> Excuse ant#y wrap....
>
> C:\Users\David>ntpq -pn pixie
> remote refid st t when poll reach delay offset
> jitter
> ==============================**==============================**
> ==================
> o127.127.20.1 .PPS. 0 l 3 16 377 0.000 -0.002
> 0.002
> uk.pool.ntp.org .POOL. 16 p - 1024 0 0.000 0.000
> 0.002
> +192.168.0.1 .PPS. 1 u 29 64 377 0.150 0.029
> 0.041
> +192.168.0.2 .PPS. 1 u 3 64 377 0.233 0.028
> 0.027
> -91.212.90.20 89.36.197.2 3 u 1057 1024 377 18.130 3.258
> 4.000
> -87.117.251.45 242.195.192.75 3 u 953 1024 377 19.668 2.265
> 4.685
> -109.123.121.128 158.43.128.33 2 u 53 1024 377 22.207 -9.700
> 11.722
> -85.119.80.233 193.47.164.28 3 u 323 1024 377 18.982 3.549
> 8.302
> -94.125.132.7 195.66.241.10 2 u 876 1024 377 20.969 2.886 6.127
> +94.125.129.7 195.66.241.10 2 u 280 1024 377 19.508 3.565 1.376
>
>
> I don't know whether that helps.
> --
> Cheers,
> David
> Web: http://www.satsignal.eu
>
>
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