Re: Apple II VGA video card and the IIgs

[bieling@terra.es (Jorge Chamorro Bieling)]

Charlie <charlieDOTd@verEYEzon.net> wrote:

> 
> The IIgs Super Hires mode pixel data resides at $2000 to $9CFF of the aux
> 64K bank which if I'm not mistaken is both bank $01 and $E1 (one shadows the
> other).
> Following the pixel data ($9D00 to $9DC7)are 200 scan line control bytes
> (one for each scan line). At $9E00 to $9FFF are the 16 color palettes.

Charlie,

Then you have to set some softwitch to enable bank $xx before writing to
the pixel map ?

Does the IIgs use the same mechanism as the IIe to access the memory in
banks beyond the first 64k "bank 0"?

Or, given that it has a 24 bit address space there are not "64 banks" to
shuffle in and out but a contiguous memory map instead and no
softswitches to set ?

Another way of making the same question is: The IIgs specific video
modes are accesible while the IIgs is in Apple II compatible mode of
operation (if such a mode exists, I think it does) ?

And if the memory map is not fragmented in banks, is there any chance
for a card sitting in a slot to guess somehow about the missing a17..a23
address lines ?

Is there IIgs-specific slot in the IIgs that is different from the Apple
II slots ?

And, the Apple-II-like slots in the IIgs are identical to the real Apple
II slots or not ? If not, what's the difference ?

Regards,
-- 
Jorge Chamorro Bieling