Need advice for a CAN project

Presumably you were handed this project assignment by a real live human being -- perhaps you should do what folks in industry do when faced by a vague spec and ask for clarification?

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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

The ambiguity in the project spec is almost certainly intentional, and no doubt you will be marked at least in part on how you approach handling the uncertainty. "Do my homework for me" posts on Usenet probably score low. Entering into a meaningful dialogue with the professor with the aim of reducing ambiguity probably scores high.

pete

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pete@fenelon.com [Support no2id.net: working to destroy Blair's ID card fraud]

Oh, I don't think it's that bad. He states up front that he's an engineering student, and he's asking us to "shed light" on it, not answer it.

I mean, I once had a kid ask me to finish his senior project for him _for pay_ as a consulting project. I didn't realize it at first, but when it became clear to me what was going on I asked for his prof's phone number -- he said never mind, hung up and never called back. It was his manner than made me suspicions -- I think he was basically honest but desperate. Had he been a conniving rat he could have cloaked his approach well enough that I would have never realized what I was doing the work for.

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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

I just wonder what's going on in Indian educational units, as the newsgroups have been flooded with clueless students from India for a couple of weeks.

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Tauno Voipio
tauno voipio (at) iki fi

Judging from the place I work, the answer to that is "implement something that seems like a good idea, ignore the insufferable systems issues that will, as a result, plague all peripherally related products for the next 50 years, and delay the project's release until some other sucker can be found to take over the ISO files".

Read the News, programming is big there. Big money, the colleges have to push out the numbers. Just like the U.S. Dot Com boom.

At that level of skill, no problem for us Westerners. What seems wrong for the students is the cluelessness of the instructors.

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Tauno Voipio
tauno voipio (at) iki fi

They want you to make a device that can monitor a CAN network. Maybe you'll be anyalyzing a CAN network that controls audio routing through main or backup radios.

Whatever controller you choose for CAN (and there are a large number of them - look at maxim [dallas parts] , microchip and ST micro to name just a few) it won't do the physical layer for you.

For that you'll need a CAN transceiver (lots of those too - see TI for a typical selection good for either 3.3V or 5V logic).

The microcontroller you choose should have a CAN 2.0B controller onboard, and then you'll need to implement the higher level logic in software.

So your microcontroller interfaces to (or perhaps is) your logic device, and the CAN transceiver is what you need to get to the physical CAN bus (make sure it's terminated ;)

Cheers

PeteS

Hi guys,

Challenging assigment. What I would advice you is use a tool like CANOE for overall performance testing. And there's another tool called CANstressor. This tools enables you to introduce single faults. On the internet you can find more info. If you cannot find send me a mail (included in

select Contact) . You can also look on my site: and select CAN. here you'll find a lot of info regarding the CAN protocol.

Succes John Ploeg The Netherlands

Thanks a lot guys. Yea, we finally managed to corner our guide and asked him to give us a clearer picture. We kindda have an idea of what we are trying to do now. But is it possible to ( and I know I may sound really stupid in saying this) make a CAN controller instead of buying a ready made 1 from the market. You know.. maybe some kindda device for protocol conversion followed by a voltage converter...

Possible: sure. After all, the companies who make the CAN controllers you find on the market have to have built those things more or less from scratch, right?

But it would almost certainly be a complete and colossal waste of your time to do that, if the goal is to *use* CAN bus for something. Sort of like starting out on the project of building a car by planting a couple dozen rubber trees to eventaully have material for tires.

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Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.