[Coco] Odd behavior

[Gene Heskett]

On Tuesday 17 December 2013 16:56:10 Chad H did opine:

> I've never owned or used a MPI.  Were they all CoCo 3 compatible?

Quick answer, No.

Long answer:  The decoding in them for slot selection responds to the data 
being sent to the gime, function as the memory mapper, by responding to 
writes to the gime at $FF90-9F.

The MPI's own control register is at $FF7F, so it can switch slots when the 
gimme is written.  There are conversion kits to isolate that, I believe 
Mark has then at Cloud9North that you can install if you solder well, or 
Mark can fix it.  The kit isn't all that much, but labor is still labor.

> Sent from my Transformer Infinity
> 
> Bill Gordon <cwgordon at carolina.rr.com> wrote:
> 
> I have been fortunate enough to happen upon another Coco3 that I could
> afford, but the ONLY problem with it is that it will NOT work with an
> MPI.
> 
> 
> 
> When the MPI is hooked up, the only display I get is a green screen-no
> garbage, no nothing.
> 
> 
> 
> That's even if the MPI is OFF or ON. Otherwise, the MPI works great with
> my original Coco3.
> 
> 
> 
> Ideas?
> 
> 
> 
> Thanks

Cheers, Gene
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