NTP Server for QNX 6.1 (or 6.2)

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Michael Nunan

NTP Server for QNX 6.1 (or 6.2)

Post by Michael Nunan » Thu Aug 08, 2002 6:11 am

Has anyone ported the NTP server code to Neutrino? I have an app with a
connected GPS board (serial with 1pps) that needs to discipline the CPU
clock. I believe that NTP will do what I want.

Thanks

David Gibbs

Re: NTP Server for QNX 6.1 (or 6.2)

Post by David Gibbs » Thu Aug 08, 2002 2:47 pm

Michael Nunan <m.nunan@ieee.ca> wrote:
Has anyone ported the NTP server code to Neutrino? I have an app with a
connected GPS board (serial with 1pps) that needs to discipline the CPU
clock. I believe that NTP will do what I want.
I think NTP stands for "Network Time Protocol" and is for receiving/
distributing time accross the network.

If you have a local accurate time source (GPS), and are only disciplining
the local CPU's clock, then NTP is kind of overkill.

You want:

-- get GPS time [ read() & translate ]
-- get OS time [ clock_gettime() ]
-- compare & determine drift
-- resynch clock [ ClockAdjust() ]

-David
--
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.

Robert Krten

Re: NTP Server for QNX 6.1 (or 6.2)

Post by Robert Krten » Thu Aug 08, 2002 2:58 pm

David Gibbs <dagibbs@qnx.com> wrote:
Michael Nunan <m.nunan@ieee.ca> wrote:
Has anyone ported the NTP server code to Neutrino? I have an app with a
connected GPS board (serial with 1pps) that needs to discipline the CPU
clock. I believe that NTP will do what I want.

I think NTP stands for "Network Time Protocol" and is for receiving/
distributing time accross the network.

If you have a local accurate time source (GPS), and are only disciplining
the local CPU's clock, then NTP is kind of overkill.

You want:

-- get GPS time [ read() & translate ]
-- get OS time [ clock_gettime() ]
-- compare & determine drift
-- resynch clock [ ClockAdjust() ]
which is what NTP does :-) Actually, FYI, a lot of the NTP software out
there has support for inputs from GPS time sources, radio clock sources,
etc.

It may be overkill, but it's "done" -- no need to reinvent.

Cheers,
-RK
--
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.

Peter Weber

Re: NTP Server for QNX 6.1 (or 6.2)

Post by Peter Weber » Fri Aug 09, 2002 7:36 pm

Do you get NMEA sentences over the serial line from the GPS?
If so, drop me a note I will send you a small library which translates the
NMEA and sync's your CPU.
It is written for 425 but compiles also on 6.1/2.
cheers, Peter
"Michael Nunan" <m.nunan@ieee.ca> schrieb im Newsbeitrag
news:ait1g6$3tg$1@inn.qnx.com...
Has anyone ported the NTP server code to Neutrino? I have an app with a
connected GPS board (serial with 1pps) that needs to discipline the CPU
clock. I believe that NTP will do what I want.

Thanks

Michael Nunan

Re: NTP Server for QNX 6.1 (or 6.2)

Post by Michael Nunan » Sat Oct 12, 2002 4:04 pm

Sorry for the delay.

I ended up doing it myself - but it is not trivial.
I am using a chipset specific set of binary, rather than NEMA, messages as
the timing is specified / fixed WRT the 1 PPS signal.
It seems to be working fine - I am managing to keep the CPU clock within a
couple of ms of GPS time.

"Robert Krten" <nospam86@parse.com> wrote in message
news:aiu0ua$qh3$1@inn.qnx.com...
David Gibbs <dagibbs@qnx.com> wrote:
Michael Nunan <m.nunan@ieee.ca> wrote:
Has anyone ported the NTP server code to Neutrino? I have an app with a
connected GPS board (serial with 1pps) that needs to discipline the CPU
clock. I believe that NTP will do what I want.

I think NTP stands for "Network Time Protocol" and is for receiving/
distributing time accross the network.

If you have a local accurate time source (GPS), and are only
disciplining
the local CPU's clock, then NTP is kind of overkill.

You want:

-- get GPS time [ read() & translate ]
-- get OS time [ clock_gettime() ]
-- compare & determine drift
-- resynch clock [ ClockAdjust() ]

which is what NTP does :-) Actually, FYI, a lot of the NTP software out
there has support for inputs from GPS time sources, radio clock sources,
etc.

It may be overkill, but it's "done" -- no need to reinvent.

Cheers,
-RK
--
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.

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