On Nov 5, 2013, at 5:24 AM, "John Dill" <[email protected]> wrote:
> The IRIG Time Code Generator used is from ITS (GPS/IRIG B Time Code
> Generator/Reader, Model 6115G), and it outputs an IRIG-B time code signal
> which does not have the year embedded in it, so it's pre-2004 standard.
...
> We have a CNIC-A2P3 board installed in a Compact PCI chassis.
Unfortunately, GE won't let me get either the hardware manuals for their ARINC
664 devices or the cpcap manual.
I'm guessing, perhaps incorrectly, from the "pcap" in "cpcap", that it provides
a libpcap-compatible API.
The folks at GE *could* have, somewhere in the path between the hardware and
the caller of cpcap:
gotten the current year number;
calculated the number of seconds between January 1, 1970, 00:00:00 UTC
and January 1, {current year}, 00:00:00 UTC (except for leap seconds - don't
ask, that's why I say "seconds-since-the-Epoch" rather than "seconds since the
Epoch");
added that to the "fractions of seconds since the beginning of the
year" value from the IRIG-synchronized counter;
when the IRIG time stamp overflows into the next year, increment the
year number and recalculate the "number of seconds since..." value;
and provide *that* value as the packet time stamp (which they *especially*
should have done if cpcap has what they intend to be a libpcap-compatible API!).
*Did* they do so, or do they just provide a "fractions of seconds since the
beginning of the year" value?
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