I2C buss

e14 Contributor over 13 years ago

Can an Arduino UNO communicate to 4 other UNO's via the I2C buss?

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michaelkellett over 13 years ago in reply to e14 Contributor +1

@Andrew, I agree with you that a very long test may not be that informative but there are also (reasonably common) cases when error detection does little to help. If, for example, the system timing is…
e14 Contributor over 13 years ago in reply to gdstew +1

If anyone interested in defining "distance" problems would like to check I believe page 60 of the most recent I2C manual "UM10204", has a note with regards to bus lengths above 10 cm requiring careful…

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0 phoenixcomm over 13 years ago

you might be able to extend the distance MAYBE by using shielded twisted pair. or change the driver receiver to a pair of Differential transmitters and receivers.

enjoy,
Cris H

And please lets not have any more pissing contests.
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0 mcb1 over 13 years ago in reply to phoenixcomm

@Christina

I agree with the last line.

Unfortunately the OP has probably gone into hiding, rather than sharing the answers for what he wanted to pass and why he selected I2C.

RS485 is a great medium and simple. We use it on some noisy communication cables over 1.2km long and it works great, plus it is isolated.

Mark
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0 michaelkellett over 13 years ago in reply to mcb1

@Mark,

Sorry to be a pain but RS485 isn't isolated http://en.wikipedia.org/wiki/RS-485

although it has some virtues.

Shame the OP has gone to ground but on balance this thread has probably provided a good deal more light than heat

MK
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0 mcb1 over 13 years ago in reply to michaelkellett

Michael
Unfortunately Maxim might like to disagree.
http://www.maximintegrated.com/datasheet/index.mvp/id/1020

So I'm not sure who isn't playing by the rules.

It is a shame the Op has gone to ground (although not surprising) as we may have to been able to resolve his issue.

Mark
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0 michaelkellett over 13 years ago in reply to mcb1

Hello Mark,

Maxim make an isolated RS485 transceiver, but isolation is not part of the RS485 spec. There are isolated transceivers for RS232 (eg LTM2882) and a great many other interfaces as well. If you like you could design an isolated I2C interface (http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=slyt403).

So the point was that RS485 doesn't imply or require isolation.

MK
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0 michaelkellett over 13 years ago in reply to mcb1

Hello Mark,

Maxim make an isolated RS485 transceiver, but isolation is not part of the RS485 spec. There are isolated transceivers for RS232 (eg LTM2882) and a great many other interfaces as well. If you like you could design an isolated I2C interface (http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=slyt403).

So the point was that RS485 doesn't imply or require isolation.

MK
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