[ntp:questions] Sure GPS - PPS not working

David Taylor david-taylor at blueyonder.co.uk.invalid
Mon Dec 9 19:47:40 UTC 2013


On 09/12/2013 18:11, Chris North wrote:
> Many thanks for your help, David. Having now sorted out the mess I had
> made of my Win 7 COM drivers, I have both 7 and 8.1 working properly.
>
> I'm considering a Raspberry Pi standalone server. But, even after
> reading your excellent account, I am not too confident about the Linux
> stuff. I'll probably get hold of a Pi for experimenting. Did you get the
> Sure GPS working with the Pi?

Chris,

I very much share your own confidence level in Linux.  I find myself 
even having to look up basic commands like how to move a file, delete a 
non-empty directory etc.  However, the folks here and elsewhere have 
been very patient, and very helpful, so the instructions on my Web site 
are part of my way of saying thanks to the community.  I won't say 
you'll have no problems, but there should be help or notes around.

I've not actually tried the Sure with a Raspberry Pi, as both my Sure 
cards were tied up with "real" NTP servers, and I wanted to try 
something a little smaller.  My current preference is a card which 
requires no soldering at all:

 
http://ava.upuaut.net/store/index.php?route=product/product&path=59_60&product_id=95

and which can take an external antenna connection so you can use a 
magnetic puck mounted in the best receiving location.  If you can get 
your Pi within sight of some sky you can try the Adafruiut module:

   http://www.adafruit.com/products/746

which can also have an external antenna via a rather small connector. 
There should be no trouble using the Sure card, though, but you would 
need to attenuate the signal down to 0..3.3 V rather than having it at 
RS-232 voltage level, or even TTL level.  The Sure board has 3.3 V PPS 
output, so that should be OK.  I don't recall testing the USB port, 
except perhaps in the very early days, but the RPi will take serial over 
USB - you may need the right drivers, though.

You'll have fun with the RPi - any disaster with the OS simply reprogram 
the SD card.  Get an 8 GB card if you intend to do much, for just an NTP 
server a 4 GB card will be fine, but 8 GB allows more scope e.g. if you 
want to do much recompiling.  You can backup the card onto a Windows or 
Linux PC easily.
-- 
Cheers,
David
Web: http://www.satsignal.eu



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