[Coco] Key-264K

[Phill Harvey-Smith]

Willard Goosey wrote:
> On Thu, Apr 23, 2009 at 04:53:42PM -0400, paulh96636 at aol.com wrote:
>> Key-264K lets you use both banks of 32k in a coco-2 which has 64kb prime ram installed.? You can run two
>> separate basic programs, one in each bank, or take advantage of the 64kb ram with one program.? Download the ZIP
> 
> Huh.  OK, I see (sort of) how that works.  I didn't know the CoCo2 had
> that kind of bank-switching tech installed.  Much becomes clear, now.

Yeah it's the page bit on the SAM, will page between two banks of 32K in 
the $0000-$7FFF range, but only in mode 0 (RAM/ROM) if you have 64K of 
ram. The page bit has no effect in mode 1 (all RAM).

Technically I suppose if you installed 32K of static RAM in the upper 
32K, plus apropreate disabling of the ROM, you could have nearly 96K of 
memory on a Dragon or CoCo 1/2.

> I'd never heard of it, but then I started with the CoCo3... ;-)

Where of course it's probably one of the SAM things that the GIME does 
not emulate.

Cheers.

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.