[Coco] Update: os9gen on 128k coco3, rs323 pack

[Steven Hirsch]

On Sun, 15 Feb 2009, Michael Furman wrote:

> I tried using the rs232 pak ROM and it seems to hang occasionally.

There's an obscure problem with interrupt handling that might be behind 
the hangs.  I have no personal experience with it, but it's written up in 
"Tandy's Little Wonder" (Farna Systems?).  IIRC, interrupts are not 
properly shared between the cartridge slot and the GIME with the end 
result being that SIO interrupts can be lost.  Again, just speculation 
that this is the issue!

> I'm using an MPI that has not been modified for use with a coco3.  I need to 
> order a new PAL and get this done.

If it's a small beige unit, you're looking at more than a PAL replacement. 
There's a gate that needs to be added in order to prevent address aliasing 
into a region that's owned by the GIME chip on the CoCo 3.

Not rocket science, but a good few hour's work.


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