Re: Apple IIx

[Rubywand <rubywand@swbell.net>]

Jeff Blakeney writes ...
> 
> On Tue, 29 Jun 1999 18:02:49 -0500, Rubywand <rubywand@swbell.net>
> wrote:
> 
> >     Another bad decision was sticking with the old Slots. A pure GS could
> >have had Slots with complete addressing and some useful interface signals
> >which would have made graphics expansion via a Slot card  feasible.
> 
> Don't the slots already have all the addressing stuff?  After all, the
> 65816 only has 16 address lines and 8 data lines.  The data lines
> double as both the high byte of the address and as the data bus.
> Standard Apple II slots have 16 address lines and 8 data lines.
>

     What you want is to have all of the Address lines, including the
demultiplexed upper bits, available.


 
> What other interface signals are you have wanted?

     If you could get the output of the Video Controller IC to a Slot, it would
be easier to add a plug-in VGA video card which could pass through current video
modes and add new modes.



> 
> I think the biggest limiting factor on the slots in the 1 MHz bus.
....

     With no Mega and no FPI, you would not be slowing down the Slot bus (or
anything else).  Base system speed could have been set to 4MHz.



Rubywand