Re: CFFA V2.0

[bieling@terra.es (Jorge Chamorro Bieling)]

Liam Busey <buseyl@yahoo.com> wrote:

> Vince Briel wrote:
> > I recently got my CFFA to work with my original Apple II. To do that I had
> > to swap out the integer basic ROMs for applesoft so that I could boot
> > prodos. I have a ROM card somewhere but it also has integer basic. Can't I
> > just swap out the integer basic in the ROM card so I can boot prodos 1.0?
> >
> > Is there an easier way to boot prodos on a original II that has integer
> > basic in ROM?
> 
> Hi Vince, I've not verified this but it is my understanding that if you
> put a firmware card in one of the Apple's peripheral slots (not slot 0)
> and activate it, the firmware on the card will replace the firmware on
> the board without interfering with a language card. If this is the
> case, a 64K Apple II with an active Applesoft firmware card in one of
> its peripheral slots is effectively a 64K Apple II+ and will therefore
> allow much more flexibility in running Prodos.
> 
> Liam

Liam,

I think that both the firmware card and the language card drive low the
/INH signal on the peripheral slot in order to disable onboard ROM and
to gain control of the ROM address space.

But if a firmware card is plugged in and activated (with the switch set
to on), whenever the language card is activated :

-It will drive /INH low to disable onboard ROM,
-but /INH will already be driven low by the firmware card, and
-The ROM on the firmware card won't be disabled by this action,

And a bus fight will happen for reads in the range $d000-$ffff.

Hmm, I'm thinking that you could still perfectly write to the language
card, though, so this combination would basically behave as a
Write-Only-Memory... :-)

Well I never tried that, so I may be perfectly wrong.

Regards,
-- 
Jorge Chamorro Bieling