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Author Topic: some pics communicated together  (Read 6166 times)

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ScubaCap

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some pics communicated together
« on: March 03, 2008, 00:58:49 AM »
Suppose that we have one big net with several pics connected with a 2 or 4 wires as a canbus.

Is there any ready protocol and hardware? is it hard to develop one?

Alex

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Re: some pics communicated together
« Reply #1 on: March 03, 2008, 11:58:48 AM »
well you will need to make one nice error free self correcting and whatever else protocol for this, and also a very good way of connecting them, as each pic is not capable to send signal to many other...
You will need to have some good tests!

kam

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Re: some pics communicated together
« Reply #2 on: March 03, 2008, 12:21:17 PM »
I had once make a very nice protocol for connecting 254 pics together. I used 15 volts for the canbus and i had a  converter on every pic that had 2 transistors, one for receiving and one for transmittin. The same can bus was supplying pics with power. It had only 2 wires! And this was the great thing!

It worked but i had some very serious problems. I have still not solve them. I keep on trying.
You know, a protocol may get very hard job to do because you want it to be fast and reliable.

ScubaCap

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Re: some pics communicated together
« Reply #3 on: March 04, 2008, 22:17:28 PM »
So? Is this too complicated? Is this too difficult? I think there are some ready protocols that should fit me. I just hapens not to know them yet  :-\ :-\

kam

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Re: some pics communicated together
« Reply #4 on: March 05, 2008, 08:12:44 AM »
In a word: Yes, it is

Alex

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Re: some pics communicated together
« Reply #5 on: March 05, 2008, 19:33:09 PM »
Come on Kam it is not so complicated and difficult.
You need just to make a protocol for this. It is not like discovering the wheel or something.

manley_V

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Re: some pics communicated together
« Reply #6 on: March 05, 2008, 23:02:10 PM »
Actually alex, it is. It might look easy but it is not so easy. You cannot ensure an uninterrupted error free run so easy. It is just so many parameters that you need to think of:

What will happen on brown out
What will happen on error
What will happen on false trigger
What will happen on error reply
etc etc etc

And also, you must think of all the commands from start because afterwards is not very easy to change many things. What will be the length of each word? every sentense? etc etc etc
And the reply? Will be a reply? And the error corection? for so many pics, a simple odd/even correction is not enough.
It is really complicated

Alex

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Re: some pics communicated together
« Reply #7 on: March 06, 2008, 01:48:54 AM »
Maybe you are right. You have more expirience than me. I just thought it would be easier

kam

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Re: some pics communicated together
« Reply #8 on: March 07, 2008, 16:27:08 PM »
ManleyV is right and not only this. There are also several problems in how to connect the pics. There are several ways. And of course several problems to solve like what kind of cable to use, how external field can affect your cable, what voltage must you use etc etc etc.

It is dificult but not impossible of course. But you have to spend several hours.

manley_V

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Re: some pics communicated together
« Reply #9 on: March 17, 2008, 23:55:12 PM »
Kam, the next page (but only after you full-fill the one for the pic that you make right now, must be something for protocols and error correction technics. I have some really good articles to send you. I will mail them to you.
Get to work!  ;) ;)

kam

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Re: some pics communicated together
« Reply #10 on: March 18, 2008, 21:24:20 PM »
Sure,
I wait!