Re: Apple IIc floppy port: is it compatible with Macintosh 400k drive?

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

In article <2i7t4d$8mr@news.u.washington.edu> whit@u.washington.edu (John Whitmore) writes:
> 	I've recently acquired an Apple IIc (a medium early model,
> with a low serial number).  It would be nice to have something
> a bit better than a singlesided 5.25" floppy drive, and it looks
> like (1) the disk controller is an IWM chip, and (2) the disk
> connector is identical to a Macintosh external floppy.
> 
> 	Is it possible to use my (old, otherwise disused) Macintosh
> 400k single sided floppy drive with this beast?

Definitely not.  The Mac 400k drive (and original 800k drive) will
only work on a Mac, or on a Universal Disk Controller card in an Apple
II.

The original IIc ROM doesn't support any type of 3.5" drive.  There is
a free ROM upgrade available through Apple dealers which adds support
for a UniDisk 3.5, which is no longer made by Apple.  You may be able
to get a second hand drive via the comp.sys.apple2.marketplace group.

To check whether your IIc will already support this drive, get into
BASIC and type PRINT PEEK(64447).  If it says 255, then you have the
original ROM and need a ROM upgrade to support the drive.  If it says
0, 3 or 4, then you can already use the drive.

You should also be able to get a motherboard upgrade at the same time
to fix a potential problem with the serial ports (accessing some
modems at 1200 bps or faster).

> 	And, parenthetically, what is the pinout of the mouse/joystick
> port (I'm pretty certain THAT isn't the same as any Macintosh
> mouse)?

The original Mac mouse, as used on the Mac 128, Mac 512 and Mac Plus
is the same as the IIc mouse.  You certainly can't use an Apple
Desktop Bus mouse (used by the Mac SE and later) on a IIc.

The mouse/joystick port has the same pinout as the IIe joystick port,
with a few pins being redefined to double up their functions.  The
mouse is detected by grounding one of the button inputs (a joystick
will have this input floating or connected to the 5 volt rail while the
button is pressed).

> 	Is there a good treatment of the IIc hardware in the
> literature (I suppose I could look up twelve-year-old magazines
> in the library, but a book would be more convenient)?

The Apple IIc Technical Reference manual is undoubtedly the best
source for anything you want to know about the IIc hardware and
firmware.  It is available from Resource Central for US$30.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand