As a conclusion to this thread:
I could get overo i2c (master) talk with an atmega128 controller (slave) in a
cheap and easy way using the logic converters from sparkfun. No special
configuration is required when using i2c-dev, just use the tutorial code from
the kernel documentation.
Thank you for your help.
On Tuesday 14 July 2009 12:03:07 you wrote:
> Thank you all for your feedback. I will try today with the sparkfun level
> Tim Hunter
> On Tuesday 14 July 2009 10:02:57 Linux Punk wrote:
> > On Mon, Jul 13, 2009 at 6:03 PM, Timothy Hunter<tjhunter.dev@...>
> > > Hello,
> > > I am trying to get a gumstix overo+summit talk as an i2c master with a
> > > microcontroller (atmel atmega1280). Using i2c detect (i2cdetect -y -r
> > > 3) does not list the microcontroller, and the microcontroller does not
> > > trigger any i2c interrupt (it is properly configured as a slave). I
> > > also tested in boradcast mode with no result either.
> > > The overo core operates at 1.8V while the microcontroller works at 5V -
> > > could this be the problem? If so, do you have any schematics for
> > > bridging the microcontroller and the overo? In particular, we already
> > > have a number of ttl converters from sparkfun for the serial ports
> > > (these ones:
> > > http://www.sparkfun.com/commerce/product_info.php?products_id=8745 )
> > > Can they be of any use here?
> > > I have no problem soldering a few components together but these
> > > electrical questions are way beyond my knowledge of electronics. Thank
> > > you for your patience.
> > >
> > > Tim Hunter
> > >
> > > P.S.
> > > I do not know the status of the robotics expansion board for the overo,
> > > but it would be nice to have an interface that can readily talk with
> > > microcontrollers and serial ports without having to add logic level
> > > converters :)
> > SparkFun has a logic level shifting board here
> > http://www.sparkfun.com/commerce/product_info.php?products_id=8745
> > that claims to do i2c. I haven't tried it, but it'll probably work.
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