[Coco] 4 Port MPI PCB artwork (so far)

[Gene Heskett]

On Wednesday 04 March 2015 02:20:28 RETRO Innovations wrote:
> On 3/3/2015 3:50 AM, Gene Heskett wrote:
> > Thats looking closer Jim. Change the leds to horizontal mounts so
> > they shine straight down, & out from under the cart,
>
> I just moved them over.
>
> > add the gnd, 5v, +12
> > and -12 connections for psu and it should be about ready to test.
>
> Added
>
> > How
> > about a 4 wide dip switch to set the powerup default slot?
>
> I put the proper slide switch
> Here is the update: http://s6.postimg.org/g0u1mwfep/PCB1_2.png
>
>   * 3V3 regulator added
>   * slide switch added
>   * standoff holes added
>   * 5 pin DIN added, to use this PSU
>    
> (http://www.jameco.com/1/1/27755-p25a13d-r1b-3-wire-ac-input-regulated
>-ac-dc-switching-triple-output-table-top-power-supply.html , though any
> source for P25A13D-R1B will work)
>   * Mini USB added

Interface electronics are in the CPLD?

>   * All lines routed
>   * All power caps added
>
> Now, it's time to consider the size of the PCB.  There is some fat
> that could potentially be trimmed on the side, and a bit on the other
> side. Something to consider.

Production real estate decisions. :)  Probably based on what the board 
houses need to fit max number up on their bigger starting sheets.  OTOH, 
they are probably pretty good at putting somebody else's job's on the 
remaining 3" of width left over from your order.  Might not hurt to ask 
them how that works.

> I came up with a potential idea for a cheap 8 slot unit, using the
> last remaining IO pin on the CPLD and the fact that I will probably
> use IDE cables for the cabling.  It might be possible to "daisy chain"
> 2 4 port MPI main units, and just set a jumper on one to be the
> "second 4", or "slave" if you like IDE parlance. Something I am
> kicking around, as it would not require building a new PCB, just
> repurposing the existing one.

That seems like it would bring up a cable routing problem, unless a 
series connection scheme was used.   I think, its too early for my 
thinker, no caffeine yet either. :(  Adding a card edge pattern to the 
far end, with a separate stacking connector pair, with 2 card edge 
sockets of suitable width to do a 180 degree turnaround so the second 
one is stacked, bottom to bottom & headed back the other way, or maybe a 
wide dual row header & a short cable to make the turn around?  The 
cable, with IDC sockets crimped on would give more flexability.  That 
would have carts sticking out front and rear.  Dunno.  Just throwing it 
out to see if it sticks. :)

What SW are you using to do this?  Apparently its a bit easier to use 
than eagle, and this of course is too big for the free eagle.

> Jim

Cheers, Gene Heskett
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