Re: Apple II II+ Mountain Comp Expansion Chassis

["Bill Garber" <willy46pa@comcast.net>]

"jim symolon" <jsymolon01@SPAMattbiBAIT.com> wrote in message
news:3VwSa.92212$wk6.25083@rwcrnsc52.ops.asp.att.net...
> Michael Pender wrote:
> >
> > This doesn't sound like a "feature" to me.   IIRC Apple cards get a slot
> > select signal that tells them they are needed.  With all 8 cards on at
the
> > same time it would be like a cocktail party with everyone talking at
once
> > because the Apple II bus doesn't have a bus control/negotiation
protocol.
>
> exactly my impression.  The way I would design it would be, the ROM on
> the apple card probably "maps" each slot on the expansion unit to active
> when softswitched.  Kind of like mapping memory areas on memory cards to
> memory addresses in the address space.

Judging from the placement of the cable on the interface card,
that would be replacing one of the 74LS138's which would expand
the slot capability. As you may not be aware the Apple II is capable
of defining the eight slots as 0-7 and then again as 8-15. If the box
contains firmware to feed the Apple II, there is no reason why all
8 of the slots in the box can't be defined from slot 7. If I'm wrong
please correct me, but I believe I am reading all these manuals in
the correct way. The slots can be used through locations C000-
C7FF and C800-CFFF.

Bill @ GarberStreet Enterprises };-)
Web Site - http://garberstreet.netfirms.com
Email - willy46pa@comcast.net



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