AVR-Chat

I'm confused.  The OP only said a few inches to a vague less than a couple
of feet.  I can easily envision a single board where the path length is "a
few inches", and thus it would seem unnecessary to insert buffers or
whatever just because the "few inches" had an off-board segment.  I'm faced
with the same situation, although only distances of up to maybe a foot or
so, so could someone please give an answer based on distance rather than one
that came across to me as just blind adherence to an on/off-the-bus, er,
board, rule.   Or, alternately, explain exactly why an off-board segment of
just a few inches demands buffering or such.   Thanks, Steve

 

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Julian Higginson
Sent: Monday, January 05, 2009 9:01 PM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Comms between AVR's

 

Of course, with the infrared, you also can move away from point to point and
have much more flexibility in data addressing to and from different units,
too (if you want to spend time making your own basic data transport layer) 

Also... a wired option for multiple listeners/responders to a message is
RS485 (again, you might want some kind of transport layer in the
communications section of your firmware)

Julian Higginson
Bruttour International P/L
http://www.bruttour.com.au
Ph: +612 9987 1581

-----Original Message-----
From: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com>
[mailto:AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> ] On
Behalf
Of Julian Higginson
Sent: Tuesday, 6 January 2009 1:08 PM
To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> 
Subject: RE: [AVR-Chat] Comms between AVR's

What kind of network topology?

If you can work out a way to do point-to-point I'd go USARTS if you have at
least one spare on each AVR.
Nice and simple to use, and opens up all sorts of other comms options if you
want.
As John said, if you're going off-board, buffered signals are important. Use
standard RS232 chips. 

Or if you want something a bit more fancy - maybe try using the USARTS with
infrared transmitters/receivers?

Julian Higginson
Bruttour International P/L
http://www.bruttour.com.au
Ph: +612 9987 1581

-----Original Message-----
From: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com>
[mailto:AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> ] On
Behalf
Of Brian
Sent: Tuesday, 6 January 2009 11:34 AM
To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> 
Subject: [AVR-Chat] Comms between AVR's

What is the common comms method to use to commuicate between AVR's 
(mega series) for short distances (USART, SPI, IIC, CAN), a few inches 
to less than a couple of feet (not on the same board)? This could be 
for 2 or more AVR's. I am using IIC for my eeprom and RTC.

Brian

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