[ntp:questions] got the Sure GPS on order, how do I program it

Chris Albertson albertson.chris at gmail.com
Wed Mar 7 05:59:52 UTC 2012

I think there are two options if you are going to use the PPS signal.

1) Treat the GPS as a "three wire" serial device without handshake,
that means TX, RX and Ground.  Then PPS to DCD pin 1.  Ignore any
serial handshake pins

2) Wire up the handshake pins on the RS232 cable but  send PPS to the
DCD pin 1 of another serial port or to a parallel port.  I think using
two ports is the only way to have both hand shake and PPS.

But if you look at real GPS receivers almost all of them are just
3-wire serial devices so #1 above is the only sensible option

> Hi Terje,
> (Anyone can answer.)
> I found this old message from April by you.  Here's part of it.
> quote on ->
> I.e. the proper programming setup seems to be:
> 1: Listen to incoming chars.
> 2: After a CRLF sequence, start a timer: If a new char arrives within
> less than 40 ms, goto 1.
> 3: Send '0', start timer waiting for CD to drop.
> 4: If CD drops before any new chars arrive, we are ready to send our
> command, so send it out before the 100 ms gps timeout.
> <- quote off
> So, here's my question.  Based on your comments, the Sure board is using,
> and driving the CD line for it's own purposes.  So, if we're soldering a
> wire to the CD line on the RS-232 connector, aren't we going to be in
> conflict with the boards own functions?
> Sincerely,
> Ron
> --
> (PS - If you email me and don't get a quick response, don't be concerned.
> I get about 300 emails per day from alternate energy mailing lists and
> such.  I don't always see new messages very quickly.  If you need a
> reply and have not heard from me in 1 - 2 weeks, send your message again.)
> Ron Frazier
> timekeepingdude AT c3energy.com
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Chris Albertson
Redondo Beach, California

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