Subject: Re: ARM Linux in space?

From: "Andy Dachs" <[email-masked]>
Date: Fri, 11 Sep 1998 17:05:58 +0100

> 
> Kahum kahum. I thought the Mitel Butterfly doesn't have an MMU?
>

Ahem, well yes.  That's what you get for skim reading the datasheet- a
misinterpretation of the difference between a memory control unit and a
memory management unit :-(

This is of course worse news for the guys doing the hardware.  We had
initially been hoping for the StrongArm but the Butterfly design has
already been done and so we had to live with that.  If anyone could point
us to a reference design for the StrongArm or 7110 the situation may be
rescuable.

Andy 

unsubscribe: body of `unsubscribe linux-arm' to [email-masked]

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From: Paul Koning <[email-masked]>
Date: Fri, 11 Sep 1998 13:03:57 -0400

>>>>> "Andy" == Andy Dachs <[email-masked]> writes:

 Andy> ...
 Andy> We had initially been hoping for the StrongArm but the
 Andy> Butterfly design has already been done and so we had to live
 Andy> with that.  If anyone could point us to a reference design for
 Andy> the StrongArm or 7110 the situation may be rescuable.

You might look at the EBSA-285 card (Strongarm SA110 with 21285 system 
control chip).  That's an eval board so it may not directly fit your
needs as is, but it is very close to what you specified.  About the
only thing it lacks is dual serial ports (it has only one).  But it
has a simple slave I/O bus ("X-bus") that could easily handle a small
daughtercard with the missing comms stuff.  Come to think of it, I
understand that the original developers build such a thing (because
the first protos of the 21285 didn't have a working serial port) using 
standard 16550 style UARTs.

The board is a mid-size PCI card, but if you wanted to build a custom
design based on it, you should be able to make it fit on half that
size.  The thing comes complete with full design files, so you can cut 
& paste at will...

	paul

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From: "Neil A. Carson" <[email-masked]>
Date: Fri, 11 Sep 1998 19:20:32 +0100

> standard 16550 style UARTs.

Yep, they did. The CATS at www.chaltech.com also has two serial ports.
Though it might not fit :)

	Neil

-- 
Neil A. Carson

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From: Philip Blundell <[email-masked]>
Date: Sat, 12 Sep 1998 01:18:59 +0100

>design based on it, you should be able to make it fit on half that

If it weren't for the SIMM you could probably fit it on roughly tbree square 
inches of PCB.  Shame really.

p.

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From: Dave Gilbert <[email-masked]>
Date: Sat, 12 Sep 1998 12:15:47 +0100 (BST)

> inches of PCB.  Shame really.

Which is why I wonder why they didn't use a SODIMM as used in notebooks.
They're a bit more pricy but about 1/4 of the size. (And at the price
of the EBSA285 anyway it wouldn't make much odds!)

Dave

 --------------------------------------------------------------------   
/ Dr. David Alan Gilbert      | Running Linux on Alpha(LX) |  Happy  \ 
\   gro.gilbert @ treblig.org |   & ARM(EBSA285,old Arc)   |  In Hex /
 \____________________________|___ http://www.treblig.demon.co.uk __/

---

From: Paul Koning <[email-masked]>
Date: Mon, 14 Sep 1998 09:35:20 -0400

>>>>> "Dave" == Dave Gilbert <[email-masked]> writes:

 Dave> On Sat, 12 Sep 1998, Philip Blundell wrote:
 >> >The board is a mid-size PCI card, but if you wanted to build a
 >> custom >design based on it, you should be able to make it fit on
 >> half that
 >> 
 >> If it weren't for the SIMM you could probably fit it on roughly
 >> tbree square inches of PCB.  Shame really.

 Dave> Which is why I wonder why they didn't use a SODIMM as used in
 Dave> notebooks.  They're a bit more pricy but about 1/4 of the
 Dave> size. (And at the price of the EBSA285 anyway it wouldn't make
 Dave> much odds!)

The usual design principle for eval boards is straightforward,
obvious, and reliable design.  Neither lowest cost nor smallest size
are design goals.

Given what the EBSA285 designers did, it should be a very simple
matter to cut & paste from the schematics to get something that best
fits your specific requirements.  (If it weren't for the fact that BGA 
attachment is a bit hard for the home shop of a radio amateur, I
probably would be well into that myself by now...)

	paul