Re: Request for Product

["Michael J. Mahon" <mjmahon@aol.com>]

jboothbee@gmail.com wrote:
> cut up a IIe, keep 3 of the slots
> intact.  1 is for connecting to
> IIe MB, the other 2 are for
> plugging other cards into.  Cut
> up some ISA boards.  One
> will plug into "extraslot #1" and
> one will plug into your IIe.  You
> have 50 connections on each
> end that you need to solder.

That approach does not fit as neatly into a case, which
I believe was Sean's intent.

> Put a switch on the "extraslot"
> that switches +5 and +12v between
> the extraslot slot1/2.
>
> would switching the power off
> be enough to disable the other
> card, and allow for the powered
> card to be accessed on the bus?

No, that's not enough, nor should it be done at all.
Power should be left on on both cards at all times so
that unpowered bus tranceivers don't load the bus.

Instead, the select lines should be switched:  I/O Select,
Device Select, I/O Strobe.  That will be enough to switch
almost all cards (execptions would be that do their own
slot decoding on board--a dubious practice).

BTW, as long as neither switched card is active, it should
be possible to switch the select lines with the power on
without any problem.

-michael

8-voice music synthesizer using NadaNet networking!
Home page:  http://members.aol.com/MJMahon/