[Coco] Older MPI with CoCo 3

[Barry Nelson]

Exactly what you need to do will depend on exactly which version of the multipack interface you have and what the part number is. There are three versions that matter:
26-3024 (can be grey or white, usually grey in color)
26-3124 (white)
26-3124A (white)

The 26-3124A does not require any updates and is already compatible with the CoCo 3. I have never actually seen one of these units.
I have a 26-3024 and a 26-3124. I have updated my 26-3124 to work with my CoCo 3 using the method (more or less) described below.

For the 26-3124
http://www.coco3.com/community/2010/05/26-3124-mpi-coco-3-upgrade-1/

After this modification is applied, the M.P.I. data buffer is limited to the address range of $FF40-$FF7F as well as CTS* and SLENB*. All that is needed is a 74LS10 Triple 3-Input NAND, a spot of solder and some Kynar wire-wrap wire. This upgrade performs in an identical fashion to the Tandy MPI upgrade. 

For the 26-3024
http://www.reocities.com/idezilla/CoCoZilla/patchmpi.html

This is a patch created by Robin W. Drake that will make the Multipak Interface 26-3024 compatible with the CoCo 3 using the original PAL chip. It does require good soldering skills. You need a 74LS10 IC and Wire Wrap Wire.


> Corey Bryant coreybryant at classicpm.com 
> Mon Sep 28 19:44:06 EDT 2015
> I just picked up an older MPI off of EBay and I am under the impression that I'll need to swap out a chip or two in order for this thing to work with a CoCo 3.   What am I going to need for this?   Are the chips still available?
> 
> Thanks!
> Corey