On 04/28/2011 09:15 PM, D Finnigan wrote:
The bus and I/O signals are always available to a peripheral card in slot 3,
even when the 80-column hardware and firmware are operating. Thus it is
always possible to use this slot for any I/O peripheral that does not have
built-in firmware.
Unless it (ab)uses the IOSEL signal for some other purpose than
firmware, which some cards do even though they have no on-board
firmware: e.g. Mockinboard, Phasor, Microsoft Softcard and other CP/M
cards. As they are, those won't work in slot 3 either. You'd need to
modify both the card's hardware and the software that uses it to use
DEVSEL instead of IOSEL, then it could work.
The number of cards that do work in slot 3 while there's something in
the Aux slot is thus fairly limited. I don't know much else except
accelerators that doesn't use IOSEL for anything. I think the Passport
MIDI Interface could work, IIRC it doesn't use IOSEL. Some simple
homebrew cards will probably work as well.