[hpsdr] [ATLAS] - proposed physical bus/pcb design 03March2006

[Phil Covington]

Philip Covington wrote:
> On 3/3/06, Lyle Johnson <kk7p at wavecable.com> wrote:
>   
>> Hello Phil!
>>
>>     
>>> For those interested, I'd appreciate if you'd please take a look at
>>> the documents and make questions/comments.
>>>       
>> In general I like what I see.
>>
>> A suggestion: I would like to see some small subset of a bus, maybe one
>> of the X buses so it will be supported with a 64-pin DIN connector - be
>> changes such that it is daisy chained between slots.  This makes it much
>> easier to set up things like JTAG chains, slot-based priority interrupt
>> schemes, and the like.
>>
>> Foe example Bus XC[0:7] could be broken into XC[0:3] as at present.  The
>> present wiring of XC[4:7] going to pins A[22:25] might be rewired like this:
>>
>> J1    J2    J3    J4    J5    J6
>> A22---A22   A22---A22   A22---A22
>> A23   A23---A23   A23---A23   A23--- to J1 A23 or n/c
>> A24---A24   A24---A24   A24---A24
>> A25   A25---A25   A25---A25   A25--- to J1 A25 or n/c
>>
>> I realize this can be done by cutting on the board, but the X traces are
>> inner layer and the Y traces are only on the 96-pin connectors.
>>
>> Alternately, this could be done on the Y traces and just accept the fact
>> that this is a "high end" feature and thus only supported on 96-pin
>> boards.  This restriction, however, means that any intervening boards
>> must also be 96-pin, which limits it usefulness.
>>     
>
> Hi Lyle,
>
> Actually, I had already made a provision for this possibility.  The
> XBUS (on the bottom of the board), and the YBUS (between the two plane
> layers) are routed between the J7-J20 pins on their respective layers.
>   The actual short traces (0.200" long) from the J7-J20 headers to the
> slot connectors (J1-J6) are all horizontally on the bottom layer of
> the board so you have full access to both the X and Y lines.
>
> I will post a bottom layer trace picture and the gerbers (for those
> who want to see them in a gerber viewer program) later today when I
> get a chance.
>
> 73 de Phil N8VB
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>   

Lyle,

I have posted a pdf of the bottom layer (layer 4 XBUS) here:

<http://www.philcovington.com/HPSDR/ATLAS/Atlas_layer4.pdf

73 de Phil

-- 
Philip Covington
Research Assistant 2 - Engineer
-----------------------------------------------------
Imaging Sciences Laboratory
Department of Astronomy
The Ohio State University
4064 McPherson Lab
140 West 18th Avenue
Columbus, Ohio 43210-1173
-----------------------------------------------------
Phone: 614 247 4374
email: pcovington at astronomy.ohio-state.edu
web: http://www.astronomy.ohio-state.edu


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