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Re: Microsoft Z-80 Card on Apple II+



Michael J. Mahon wrote:
In article <20030402080603.23178.00000614@mb-fh.aol.com>, quadrajet1@aol.com
(Quadrajet1) writes:


<< >   The reason I thought the AE card may work is it was made a lot later
than the

MS card.  Plus if I recall they made 2 versions, one with a red LED and one
with a green LED.  I think one was 4 Mhz, the other was 6?

Steven N. Hirsch replied:

No. They were all MS knockoffs and ran at an effective 2Mhz. You may be getting thrown by the speed rating of the CPU chip, which has nothing to do with how it actually operates in circuit.

I beg to differ, there was 2 different versions of the AE Z80 card.  I'd
have
to do some research on that, but most of my materials from that era is
buried.
We used to sell them back when they were new.  AE never really knocked
anything
off, they made it better.  I have seen Taiwan knockoffs that even copied the
silkscreen so the card would still say Microsoft (or whatever) on it.  But
you
could tell a mile away from the quality of the workmanship.


I do not have an AE Z80 card, but I suspect that what Steven meant
by "knockoff" is that the AE cards use the same address mapping
and clocking scheme.  This would make them "compatible" with
the SoftCard, but also susceptible to the same bus timing issues.

What Mike said. I knew the hardware designers at AE personally, BTW. Steve Malachek was responsible for the AE Z80+ card which I'm familiar with. It's possible that some redesign took place later, but I'm not directly aware of it. Many years under the bridge since then <g>..

Steve