[Coco] New MPI project for brazilian clones

[RETRO Innovations]

On 1/21/2016 8:38 AM, camillus gmail wrote:
> Hi,
>
> Ask for Jim on this list, he is at the brink of releasing his project of an MPI. Based on CLPD , so iI heard it is capable of having more slots, the first proto I saw was at cocofest 2015 an it had two boards, the interface that plugs into the coco and the slots are on other board. The connection is made by two flatcables.
> I'm not sure what the status is now, but you can always inform on this list.
>
>
> cb
> On 1/21/2016 5:00:52 AM, Daniel Campos <daniel.campus at gmail.com> wrote:
> Hi,
>
> We are gathering here in Brazil to make a MPI that would be usable on the
> CP-400 and other brazilian clones as well. This MPI will be a little
> different because it will have a flat cable to connect on the tiny CP-400
> slot.
> We are thinking to follow and adapt this design here:
>
> https://sites.google.com/site/tgmaxx/tandy-color-computer/expansion-interface
>
> Anyone have tried to build this project before? It works well on
> CoCo1/CoCo2 machines?
>
> Thanks!
> Daniel
>
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> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco
>
I am here, lurking and working on the MPI.

The good news is that the unit works well.  The cable length was an 
issue, but I believe I have moved beyond that.

I used the same design as a base, but moved all of the functionality 
into a CPLD, as it minimized the design a lot and the cost as well.

A picture of the unit is on page 12:

http://www.glensideccc.com/data/library/newsletters/gccc35_2nl.pdf

If the pinout of the CP-400 is similar, you should be able to just make 
a new "head end" and use the same expander design.

The design is open source (HW CC-BY-SA, and CPLD firmware GPLv2), but I 
have not published yet as I am making final changes, including:

I am adding a relay to turn the unit on only when the computer is 
powered, or at least give the option.
I am adding an LED on the xpander so folks can tell if it is powered (so 
they do not pull or insert carts)


As Camilus notes, although the unit shows 4 (5) cart slots, the CPLD can 
handle switching 8 slots.

Jim


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