Re: IIGS Slot Management

[Hugh Hood <hughhood@earthlink.net>]

in article f5fdff10-aa6f-4426-bb75-1f3f697f4f88@googlegroups.com,
hafner.spam@gmail.com at hafner.spam@gmail.com wrote on 12/27/12 7:02 PM:

> 
> So my question is this - those of you with lots of cards in your IIGS
> machines, how do you manage them without losing the functionality built into
> those slots? 
> 

Chris,

I would recommend your considering manipulating the IIGS Slot Register
($C02D) from within your programs (either as a patch routine or as a
pre-launch routine) in order to 'toggle' between the built-in vs. 'Your
Card' options without having to visit the Control Panel and re-booting.

Basically, you read the contents of $C02D into the accumulator and use,
IIRC, the andbits operation to change just the bit corresponding to the slot
you want to 'toggle'.

I do this extensively to switch Slots 1 and 2 back and forth between several
printers and a serial connection to a Unix terminal host.

I would urge caution, however, if you use this technique on slots that have
a disk drive attached. Should you forget that you switched out your drive
and attempted to do a disk write operation, things could get very confused.

Here's a thread from a couple of years ago that might elaborate more,
although there is way more info there than you should really need. It dealt
specifically on toggling _from_ a 'Your Card' setting to the built-in serial
port setting from within the AppleWorks application. Going from a default
Control Panel 'built-in' setting to the 'Your Card' setting is much simpler
-- just flip a bit and go.

<https://groups.google.com/forum/?hl=en&fromgroups#!topic/comp.sys.apple2/_R
k6n4cOD5Y>

For more general info, just search on '$C02D' and 'slot register' and you
should find what you need, in addition to Page 282 in the "Apple IIGS
Firmware Reference".





Hugh Hood