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Communication between 2 or more duino's


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#1 Flores

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Posted 23 August 2010 - 07:47 PM

Any thoughts experiances on connecting 2 or more netduino's over a 5 meter distance? I have no idea, and was thinking of an ethernet shield, is that a good idea? Is there something better/cheaper? Thanks

#2 greg

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Posted 23 August 2010 - 07:54 PM

Any thoughts experiances on connecting 2 or more netduino's over a 5 meter distance?

I have no idea, and was thinking of an ethernet shield, is that a good idea? Is there something better/cheaper?

Thanks


Just use a XBee wireless. It's straight serial comm through the UART so it's easy.

#3 Chris Walker

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Posted 23 August 2010 - 07:57 PM

As greg mentioned, XBee would work well. Also, you could use 2 RS232 shields and a serial cable.

#4 Flores

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Posted 23 August 2010 - 07:57 PM

Just use a XBee wireless. It's straight serial comm through the UART so it's easy.


Thanks but,

forgot to mention: I want it te be wired, not wireless. And I want to connect 3 or more..

#5 CW2

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Posted 23 August 2010 - 08:53 PM

And I want to connect 3 or more..

What topology?

#6 greg

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Posted 23 August 2010 - 09:31 PM

What topology?


3 or more you've got a couple choices - you can use I2C to do it and give each a different address or you can use ethernet.

Personally, as a network engineer I'd say ethernet but there aren't any ethernet drivers for the netduino (yet!).

#7 Chris Walker

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Posted 23 August 2010 - 09:39 PM

3 or more you've got a couple choices - you can use I2C to do it and give each a different address or you can use ethernet.

Personally, as a network engineer I'd say ethernet but there aren't any ethernet drivers for the netduino (yet!).


The I2C on the ARM7X chip is master-only. We'll see what we can do on speeding up Ethernet support...

Chris

#8 pascal06

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Posted 23 August 2010 - 09:41 PM

3 or more you've got a couple choices - you can use I2C to do it and give each a different address or you can use ethernet.

Personally, as a network engineer I'd say ethernet but there aren't any ethernet drivers for the netduino (yet!).


+1 for Ethernet.
It's seems that I2C .net MF implementation (like SPI) is always master. So, we cannot use I2C to cummunicate between 2 Netduino(s). Or we need to write another driver.
And I2C is very slow for that distance.

Pascal

#9 greg

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Posted 23 August 2010 - 09:45 PM

The I2C on the ARM7X chip is master-only. We'll see what we can do on speeding up Ethernet support...

Chris



Woops - I remember seeing that but forgot.

Ethernet is your best option then if you want wired communication.

Personally XBee is a great option - inexpensive, mesh topology, wireless, variety of ranges and best of all - SIMPLE. :)

But again, as a network engineer I'd love to be able to send/receive TCP and UDP from my netduino. Come on Chris - get cracking! :)

#10 pascal06

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Posted 23 August 2010 - 09:49 PM

The I2C on the ARM7X chip is master-only. We'll see what we can do on speeding up Ethernet support...

Chris


I2C master-only is a limitation of ARM7X or .NET micro framework ?
Perhaps I'm wrong, but when I read the datasheet, it's seems that the ATMEL used on netduino support both mode, no ?

Pascal

#11 Chris Walker

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Posted 23 August 2010 - 09:56 PM

I2C master-only is a limitation of ARM7X or .NET micro framework ?
Perhaps I'm wrong, but when I read the datasheet, it's seems that the ATMEL used on netduino support both mode, no ?


From the AT91SAM7X512 datasheet:
One Two-wire Interface (TWI)
– Master Mode Support Only, All Two-wire Atmel EEPROMs and I2C Compatible Devices Supported

A driver for SPI slave mode could be written, but I2C slave would require a "bit banged driver."

Chris

#12 pascal06

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Posted 23 August 2010 - 09:59 PM

From the AT91SAM7X512 datasheet:
One Two-wire Interface (TWI)
– Master Mode Support Only, All Two-wire Atmel EEPROMs and I2C Compatible Devices Supported

A driver for SPI slave mode could be written, but I2C slave would require a "bit banged driver."

Chris


Thanks for that clarification :unsure: ...

Pascal

#13 Flores

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Posted 24 August 2010 - 06:18 AM

The I2C on the ARM7X chip is master-only. We'll see what we can do on speeding up Ethernet support...

Chris


That would be realy cool. Would even do greater distances and could use a switch for connecting them..

#14 Szymon

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Posted 24 August 2010 - 10:40 AM

That would be realy cool. Would even do greater distances and could use a switch for connecting them..


In the meantime I recommend reading the "Making Things Talk" book that dicusses many other communication technologies.
http://oreilly.com/c...g/9780596510510

Maybe it will give you some ideas. In any case let us know what you came up with.




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