[En-Nut-Discussion] RFC: Ethernut Bus System

[danny-cvs]

I think it'd better to use PC104, but I doubt that Ehternut 2 can support
PC104 spec?
----- Original Message -----
From: "Dave Smart" <SmartFamily at mchsi.com>
To: <en-nut-discussion at egnite.de>
Sent: Thursday, April 03, 2003 9:23 PM
Subject: RE: [En-Nut-Discussion] RFC: Ethernut Bus System


> Solution 2:
>
> I'd cast my vote for solution 2, PC104 connectors. I'm only familiar with
> PC104 based on pix in trade mags and some casual reading way back when,
but
> I envision Ethernut 2 as the bottom board, so would not have pins beneath
> it. Thus, Ethernut 2 would be about the same height as today. The
additional
> boards would have the full up/down connection system, and thereby be
> stackable.
>
> I do have concerns about the overall height, but that can be accounted for
> in packaging. Today my add-on board is component side down into the
Ethernut
> board, with components carefully located to not interfere when mated. This
> makes a slim sandwich, which would be a bit taller with PC104 design, but
> not much.
>
> Additional thoughts - Perhaps smaller "break-out" connectors of the DIL
type
> as used today to gain access to _sets_ of I/O. What I'm thinking here is
> that many apps may only need small subset of the I/O. If there were
several
> smaller DIL connectors that each had a port, raw and logic power and
ground,
> and were arranged on even 2.54mm spacing, then a large (64pin) mating
> connector could straddle them all for some users needs, but in another app
> perhaps a single 16pin mate would be sufficient. (I hope this paints the
> same picture in your mind like mine)
>
> perhaps this will show the concept.
>
> * * * * * * *   * * * * * * *   * * * * * * * 3 sets of 14 pin headers
> * * * * * * *   * * * * * * *   * * * * * * *
>
> * * * * * * * * * * * * * * * * * * * * * * * * overlaid with single 48
pin
> header
> * * * * * * * * * * * * * * * * * * * * * * * *
>
>
> The other thought when you mention PC104, and again with perhaps enough
> knowledge of that system, is to be pin compatible to that environment. The
> perhaps standard PC104 options could be used, or if Ethernut ever migrates
> to another CPU that is already supported, the breadth of devices in that
> environment is quite wide.
>
> Solution 1:
> I don't know about the 96 pin DIN, but your comment "large" is a
deterrent.
>
> Solution 3:
> "unreliable" puts my thumb down.
>
> Solution 4:
> I'm always challenged to make things smaller, but perhaps this makes the
> cost go up significantly with a single source as well as risk of [lack of]
> availability?
>
>
>
>
> -----Original Message-----
> From: en-nut-discussion-admin at egnite.de
> [mailto:en-nut-discussion-admin at egnite.de]On Behalf Of Harald Kipp
> Sent: Thursday, April 03, 2003 6:07 AM
> To: en-nut-discussion at egnite.de
> Subject: [En-Nut-Discussion] RFC: Ethernut Bus System
>
>
> Hi all,
>
> As you may know, Ethernut 2 will be plug-in compatible to
> Ethernut 1.
>
> For long term planning I'm considering some kind of bus
> system for easy add-on board design. I already discussed
> this in some private emails, but would like to get more
> people involved.
>
> One thing I'd like to discuss are the mechanical connectors.
>
> Solution 1: Using 96 pin DIN 41612 connectors. Disadvantage
> is, that they are very large. Advantage is, that housings are
> easily available and, because this is a backplane system,
> it's very flexible.
>
> Solution 2: Using PC104 connectors. Disadvantage is, that
> stacking up boards is limited and component height matters.
> Advantage is, that they are 2mm pitch and much smaller than
> 1" pitch connectors.
>
> Solution 3: Using SIMM connectors. They are looking very
> unreliable to me, number of pins and board size is limited.
>
> Solution 4: Using one of those very tiny (down to 1mm pitch)
> connectors offered by some manufacturers without second source
> and build a backplane system.
>
> What do you think?
>
> Harald
>
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