[LinuxPPS] Some Info about the Project I'm working on

[Rodolfo Giometti]

On Thu, Sep 06, 2007 at 06:15:09PM -0500, Adam Becker wrote:

> I wondering if and how LinuxPPS could be useful for the project I'm
> currently working on. I'm working on an embedded PC104 stack with 3
> Pentium M processors. What I need to do is accurately sync the clocks on
> each of the processors because in testing the system we found that the
> clocks drifted significantly. I have a GPS with a PPS signal. The GPS
> data is tied to one of chips via RS232 and that chip's other 2 COMs are
> connected to COMs on the other processors. The PPS signal is currently
> wired to I/O pins on the parallel ports of each of the chips (this could
> be changed) and all three currently have Ubuntu 7.04 as their OS. 

I think you don't need at all the PPS signal routed to all CPUs, but
simply you should connect one CPU with the GPS antenna throught one
serial line (both data and PPS signal) and then configure NTPD on that
system in such a way it can set its clock by using the PPS signal.

Then, on the other two systems, you should configure the NTPD daemon
in order to sync with the first CPU throught the ethernet.

Ciao,

Rodolfo

-- 

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