[ntp:questions] Re: 1pps signal,20us width
fxw115 at yahoo.com
Mon Nov 15 21:26:18 UTC 2004
It is FreeBSD 5.1, I do not have similar problem with
I used black box RS232-485/422 converter. I watched
the signal using ocsilliscope, it is clean +-12V
signal. However, the signal is distorted(rounded) a
little at rising upper left edge. Is it a problem?
--- rtxo <gnu at wraith.sf.ca.us> wrote:
> Fei Wu wrote:
> > I tried not to stretch the PPS pulse and feed it
> > RS232 port ( my pc like server ). I got the
> > error:
> > refclock_atom: time_pps_kcbind failed: Operation
> > supported.
> This seems like your kernel is not an RFC2783
> capable system. Linux needs the "PPSKit" patch, and
> freebsd 4.x should support ppsapi.
> > Does the error confirms that the pulse is too
> > for my machine?
> No, it sounds like your kernel is the problem.
> Also, you should make sure that the TTL signal has a
> proper level converter to the rs232 signal levels,
> best compatibility with pc motherboards. An MC1488
> work best. A MAX232 will also work, but adds a
> of 1.5 microseconds latency.
> questions mailing list
> questions at lists.ntp.isc.org
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