[Coco] Re: 64K Mode

[John E. Malmberg]

Brad Grier wrote:
> 
> I'm confused by this. Are you saying the P1 register at 0xffd4 and 
> 0xffd5 allows two banks of lower 32k ram? None of the 64k programs I 
> have write to this register. Are there any programs that do this?

The Color Computer SAM chip can access 64K of dynamic RAM, and almost 
32K of ROM or static RAM.

You can MAP either 32K in the bottom section, and swap the upper 32 K as 
  ROM / RAM.

There has been one example of a program that apparently is not currently 
available that takes advantage of this.

And there could easily be a ROM pack that would swap out the lower 32K 
as needed.

> According to my color computer reference manual, "Register P1 controls a 
> feature which is not used in the Color Computer. Therefore it should be 
> cleared at all times." Is that pre-64k?

The Motorola Manual explains all. :-)

-John
wb8tyw at qsl.net
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