Re: IWM and un-suitable drives for Macs

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

Wayne Stewart <waynes@intergate.bc.ca> wrote:

> The IWM on my ROM 1 & 3 IIgs are 28 pin chips.
> The SWIM  on my Super drive card and a couple of Macs I checked
> are 44 pin chips. Which Macs used a 28 pin SWIM?

The original IWM is a 28 pin DIL package (dual in-line).  Later Macs use
the 44 pin PLCC package (square pack).  This is the smallest such
package which is commonly available, and it is quite likely that the 44
pin PLCC version is functionally identical to the 28 pin DIP version.

If my recollection is correct, the original Mac 128 has a 28 pin IWM
(I've seen the motherboard, but not recently).  This was probably also
true for the 512, and possibly the Plus.  I know that the Apple IIc uses
the 28 pin version as well.

The SE and II probably use the 44 pin PLCC version, and I'd expect that
all SWIM chips are 44 pin PLCC.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand