Re: ][+ ROM Card

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

Terence J. Boldt <ter@interlog.com> wrote:

> >Ummmmm....Wait a minute...can you do that with a //e?  I thought the ROM
> >cards were intended to operate in Slot 0, which the //e doesn't have...??
> >
> >I do remember working with one machine that had a ROM card...it was an
> >Apple ][ with an Applesoft ROM card, which was kind of nice...
> 
> 
> I have two of those ROM cards and some //e computers.  Yes it does work in
> any slot.

You have to be rather careful if you have two of these cards installed
(or one at the same time as the language card in slot 0 of a ][+),
because they all use the INHIBIT signal to override the motherboard
memory.  If two of the cards are active at the same time, they will
cause a data bus clash.

I don't recall offhand whether they try to use the DMA IN/OUT chain to
avoid conflicts, but even then they would only be fully safe if in
adjacent slots.

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