Re: Slot 3 cards

[dempson@actrix.gen.nz (David Empson)]

> David Wilson wrote:
> 
> > My Platinum //e has an RGB card which plugs into both slot 3 and the Aux
> > slot connectors simultaneously.
>
> W Stewart <waynes@intergate.bc.ca> wrote:
>
> That's interesting, I didn't know anyone had made a card like that.
> On the otherhand the chances of finding a PAL IIe in Canada are  prettywell
> non existant. I've some RGB cards here but they're either Auxilary or regular
> slot. Any idea why that one would need both?

There are some signals that are only available in the standard slots,
and others which are only available in the auxiliary slot.

One possibility would be if the card has some I/O registers ($C0B0 to
$C0BF) to control the video output in some way, but also supports the
standard IIe auxiliary memory 80-column and double hi-res graphics
buffers.

Another possibility would be if the card contains firmware which
replaces the motherboard 80-column support, while retaining the required
entry points (XFER, AUXMOVE and the enhanced IIe interrupt handler).

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand