Re: IIgs ROM 01 & Z80+

["Charlie" <charlieDOTd@verEYEzon.net>]

"KP" <kjpmail@gmail.com> wrote in message 
fab247ae-34ce-4494-a030-532022e128e7@l20g2000yqm.googlegroups.com">news:fab247ae-34ce-4494-a030-532022e128e7@l20g2000yqm.googlegroups.com...
>I have a Z80+ card in Slot 4 of my IIgs ROM 01.
>
> When I use it solely as "Your Card," it works.
>
> I then switch to "Mouse Port" for a GS/OS application, reset, run 
> the
> application, and the mouse works fine.
>
> I then switch to "Your Card," reset, boot a CP/AM disk (either 
> 5.1.1
> or 4), and CP/AM doesn't properly function.
>
> Turning off the IIgs and then turning it back on does not fix the
> problem; the Z80+ and/or CP/AM continue to malfunction.
>
> Opening the IIgs, re-seating the card, and re-booting the machine 
> set
> to "Your Card," and I get another successful use of the 
> Z80+/CP/AM.
> But as soon as I temporarily switch it to Mouse and then back 
> again, I
> get the same problem.
>
> Does this sound like anything familiar to anyone on here?  I am 
> going
> out of my mind trying to figure out what I need to do to 
> permanently
> fix this.

I don't know how this would have anything to do with your problem, 
but I do think you should be careful when you put cards that were 
meant for earlier Apples in an Apple IIgs.  If the older card uses 
the /INH line and does not mask the addresses when the line can go 
low it can cause bus contention (see Apple IIGS Tech Note #32). 
Supposedly, if that happens it can damage the Mega II chip.  I have 
no idea if your Z80 card uses the /INH line but I wouldn't want to 
take the chance until I found out for sure.  By the way, the Carte 
Blanche card with the included bitstream has z80 code that uses the 
/INH line.  I don't know enough about the z80 functionality to say 
if it is masked or not.

Charlie