Re: Apple //e motherboards

["David Wilson" <mcs6502@gmail.com>]

Eric Smith wrote:
> "David Wilson" <mcs6502@gmail.com> writes:
> > I wish they didn't. In a USA model IIe you can put some cards in slot 3
> > at the same time as a RAM card in the Aux Slot. Any card that only uses
> > /DEVSEL (the 16 byte I/O space) and not /IOSEL or /IOSTB (the 256 byte
> > and 2KiB memory areas) will work without affecting the 80-column
> > firmware - eg Stellation Mill 6809 co-processor card.
>
> Or (more commonly) a Microsoft Z80 Softcard or equivalent.

The Z80 Softcard is turned on and off by writing to the IOSEL ($CnXX)
space rather than the DEVSEL memory space. I am not sure if the IIe
disables the /IOSEL signal when SLOTC3ROM is false (like the IIgs does
for most slots not set to Your Card).