On Mon, 3 Jun 2002, Nyef wrote:

> On Mon, 3 Jun 2002, David A. Gatwood wrote:
>
> > On Mon, 3 Jun 2002, Nyef wrote:
> >
> > Heh.  Well, the chip isn't exactly documented....
>
> My point exactly. ^_-
>
> What, exactly, does SWIM _really_ stand for, anyway? A quick search with
> Google turns up at least three different possibilities...

Super Woz Integrated Machine, from
_Guide_to_the_Macintosh_Family_Hardware_, section "IWM and SWIM" of
chapter 2, page 80.

> > > > 2.  Yes, HDSEL can be set in either place.  You should probably control it
> > > > on the chip where possible, despite what classic Mac OS does.
> > >
> > > Huh. I'd have thought that it would depend on the way the hardware is set
> > > up. Is this a wired-OR setup?
> >
> > Not sure.  Don't have a wiring diagram.  (Well, I probably do, but I don't
> > care that much. ;-)  To be safe, set it in both places.
>
> I'll check to see if the chip-only version works on my IIcx once I get it
> working again (-if- I get it working again)... Gonna try replacing the
> internal battery tomorrow...

According to GttMFH (Chapter 9), some systems wire floppy pin 12 (SEL) to
Via (1)'s PA5, while others wire it to HDSEL from the SWIM.

From looking at diagrams, machines using VIA (1) PA5 are: SE, II, SE/30,
Mac Portable (that huge thing they made once), IIx, IIcx, IIci. The IIfx
ran it off of HDSEL.

Since HDSEL is a no-connect on machines that use VIA(1)'s PA5, I think
it's safe to set in both places.

Take care,

Bill