Re: Presence of a IIc memory card

[Jim Marek <jmarek@seimens-psc.com>]

The Apple II Mail Group wrote:

> Surely there is a hardware peek. I just don't know what it is. I'll look at the
> AppleWorks code and try to see what it does to get the memory (AM, RM, or XM)
> manager in.

Yes, there is a hardware peek. Since the IIc and IIc+ always treat the Apple
"slinky" card as a Slot 4 device, the peek location is 1148 ($47C). The contents is
set by a ROM routine called TestSize. The value is the number of 64K banks of
expansion memory.

I ran several tests on my IIc (with the memory expansion ROM: (64447) = 3) and IIc+
to see what values I would get. I have a 1 MB card. In all but the last of these
tests I had no disk in the drive. From the Basic prompt, I went into the monitor
(CALL -151) and typed 47C<return>. I also tried running the "slinky" diagnostic in
ROM by entering C40AG<return> in the monitor.

IIc:
After power on without the memory: (47C) = 0
      The diagnostic said there was 1 MB of memory but failed immediately.
After power on with the memory: (47C) = 16 (actually 10, hex.)
      The diagnostic said there was 1 MB of memory and ran successfully.

IIc+:
After power on without the memory: (47C) = 0
After power on with the memory: (47C) = 0
      The diagnostic said there was 1 MB of memory and ran successfully.
After running the diagnostic: (47C) = 16
After booting up ProDOS: (47C) = 16

I tend to think about checking a system's resources from a program, but if you want
a easy external check for a "slinky", the diagnostic test in ROM is really useful.