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Re: [beagleboard] Re: Auto-Identify expansion boards


Gerald Coley Apr 17, 2009 12:44 PM
Posted in group: BeagleBoard
Nice way to keep the conversation going! I would like to be able to handle this. The rub here is the addressing. Let me think on ths and see how we can manage it. I know a way, but I need to see how it flows in a practical implementation. Can we set a limit of two stacks?
 
Gerald


 
On Fri, Apr 17, 2009 at 2:40 PM, Preston Wilson <rpwil...@gmail.com> wrote:

How will this work with multiple (stacked) cards?  Or is that off
limits?

I hate throwing this out there, as I have to leave, and I won't be
able to participate again until much later.

I think it is a good idea, and I have built two expansion cards, so I
have an interest in what is chosen.

-Preston

On Apr 17, 3:36 pm, Gerald Coley <ger...@beagleboard.org> wrote:
> Well, that may not be an bad idea, but I don't know if I can handle that. I
> just used up my last of 8 arms doing the EEPROM piece. Octo Man is all
> booked up!
>
> Gerald
>
> On Fri, Apr 17, 2009 at 2:34 PM, Dirk Behme <dirk.be...@googlemail.com>wrote:
>
>
>
> > Gerald Coley wrote:
> > > I think this is a good idea. I will work to come up with a standard on
> > this
> > > from a HW perspective. It will be an I2C based EEPROM of the lowest cost
> > I
> > > can find. Once I come up with that and the addressing, I will let
> > everyone
> > > know.
>
> > > We will need someone in the community to own the data format and how we
> > > format the data in the EEPROM.
>
> > Do we need a "Beagle ready" logo for expansion boards which comply
> > with this standard, then? ;)
>
> > Dirk
>
> > > On Fri, Apr 17, 2009 at 1:50 PM, Dirk Behme <dirk.be...@googlemail.com
> > >wrote:
>
> > >> It seems we get more and more expansion boards connected to Beagle's
> > >> expansion connector. Different expansion boards might need different
> > >> pin mux and other configuration changes in SW, e.g. in U-Boot and/or
> > >> Linux kernel.
>
> > >>  From the discussion at this list and at IRC we learned that
> > >> especially the pin mux configuration is confusing again and again. It
> > >> would be nice if we could avoid that each expansion board needs its
> > >> own U-Boot and Kernel (<= recompilation, x binaries). So best would be
> > >> to autodetect if and which expansion board is connected to Beagle and
> > >> then configure it automatically by SW. Example is OMAP Linux kernel
> > >> multi boot feature based on machine ID or Beagle rev Bx/rev C
> > >> detection based on GPIO states.
>
> > >> But for this we need a way to make SW able to detect which expansion
> > >> board is connected.
>
> > >> Idea was now to have something like an I2C EEPROM on *each* expansion
> > >> board which can be read by SW to get an explicit ID from each board.
> > >> This could use Beagle's i2c2 on the expansion connector (Overo could
> > >> use i2c3, btw).
>
> > >> What do you think?
>
> > >> If you like this, what do we have to standardize to make this work?
>
> > >> Best regards
>
> > >> Dirk