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RE : Solving the need for ISA or USB slots and Serial Ports




> -----Message d'origine-----
> De : owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org] De la
part
> de Timothy J. Salo
> Envoyé : mercredi 2 juillet 2003 20:10
> À : amsat-bb@AMSAT.Org
> Objet : Re: [amsat-bb] Solving the need for ISA or USB slots and
Serial
> Ports
> 
> > Date: Wed, 2 Jul 2003 11:14:51 -0400
> > Subject: Re: [amsat-bb] Solving the need for ISA or USB slots and
Serial
> Ports
> > From: David Beach
> >
> > How much effort/cost is required for an Ethernet interface on the
> > rotator controller, rather than USB/serial/parallel/etc? As more
people
> > end up with Ethernet on their home/ham computers, the idea of having
> > the rotator on the network seems appealing - 'just' connect it to
the
> > hub/router/switch and any machine could operate it. Anybody have
> > experience with this? Or thoughts in general?
> 
> If you are going to use Ethernet, you probably want to think about
> what protocols you want to run within the Ethernet frames.  With
> enough effort, you could encapsulate your rotor control protocol
directly
> within Ethernet frames.  However, an easier solution is to run
> IP over the Ethernet frames, and then run your rotor control protocol
> on top of IP (e.g., using TCP or UDP).  The advantages of IP include:
> 
> o	Many devices already support an IP stack, so your development
> 	would be limited to writing the rotor control application,
> 	rather than mucking around trying to implement network
> 	protocols directly on top of Ethernet.
> 
> o	IP potentially eliminates any distance limitations.  You
> 	could control your rotor from work, or from around the world.
> 	Of course, if you don't secure your Internet-attached
> 	rotor, then potentially anyone else on the Internet could
> 	control it as well.
> 
> My favorite embedded Ethernet single board computer (SBC)
> is the Dallas Semiconductor TINI board.  This SBC has a
> reasonably good Java implementation.  Some time ago, I
> wrote some Java software that beaconed APRS frames.  Since
> my balloon project hasn't yet gotten off the ground, the
> software also simulated the output from a GPS receiver.
> Of course, not having the patience for a (simulated)
> three-hour balloon flight, I transmitted beacons fairly
> quickly.  Unfortunately, the APRS Internet backbone
> filtered most of the packets, but I still got a nice
> track on FINDU.
> 
> The same software ran on my PC and on my TINI board with
> only two changes:
> 
> -	I had to remove one "include" statement
> -	The names of the serial ports are different on
> 	the PC and the TINI
> 
> Obviously, my next suggestion is that you write your
> software in Java, rather than a platform-specific
> language.  Using Java offers the prospect of running
> the same software on a variety of software platforms,
> including Windows PCs, Linux PCs, Linux non-PCs, etc.
> By the way, you might even be able to run your software
> on your Palm, although the GUI code will be radically
> different between the PC platforms and the Palm.
> 
> (Every time I write this, several people send me e-mail
> saying that they don't know Java, and have no interest
> in learning it.  I don't remember if it is the same
> people every time.  You may find that learning Java
> is a lot more useful than, say, 20 WPM code.)
> 
> 
> There are numerous non-Java embedded SBCs that come with
> an IP stack.  They could also be used, although you would
> be more likely to program them in a legacy, and largely
> non-portable, language such C.
> 
> By the way, the TINI processor is $50 - $67 (for 0.5 or 1.0 MB,
> respectively), and you probably want the $35 "socket" that
> provides power regulation and connectors.
> 
> -tjs
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the
author.
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The Tini board seems very interesting. I look to use it for a rotator
controller based Amsatdrive
(http://www.amsat-france.org/amsat-drive/index.htm). Currently, I wait
for  the Tini board which I ordered. 

I am very interested by your experience with this kind of hardware.

Java is an interesting language. I wrote the JCP ( Java Client for
Predict) software which is able to display satellites calculated by
Predict (http://www.qsl.net/kd2bd/predict.html) . 
The JCP software is available at http://www.avmdti.org .


Christophe Mercier
Secrétaire Amsat-France
mail to : c.avmdti@free.fr



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