sehrlich@lynx.northeastern.edu (01/18/91)
For those of you who wanted to know of some of the responses I
received from my question about the differences in the original
Apple ][c computer, here was one of the more informative responses
I got:
Hi there, I'm a friend of Pete's - a roving Hacker you might say.
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The Apple //c Family
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Changes have been made to the Apple //c since the original version
was introduced. The first change was made in order to support the
UniDisk 3.5 external drive, and included a set of ROM-based
machine-language routines called the PROTOCOL CONVERTER. The
latest version incorporates all the UniDisk 3.5 upgrade features, a
new version of the Protocol Converter called the SMARTPORT, and
support for an optional memory expansion card.
Note: Smartport is merely a new name for the Protocol Converter
all the specifications for the Smartport apply to the
Protocol Converter, and vice versa.
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Identifying Your Apple //c
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There are basically three version of the Apple //c:
o the ORIGINAL Apple //c
o the UNIDISK 3.5 Apple //c
o the MEMORY EXPANSION Apple //c
You can tell which Apple //c you have by checking the value of the
ID byte at ROM location 64447 ($FBBF in hexadecimal). The value of
this byte is 255 ($FF) in the original Apple //c, 0 ($00) in the
UniDisk 3.5 version, and 3 ($03) in the memory expansion version.
Checking the ID byte: You can check the value of the ID byte
from Applesoft by typing PRINT PEEK (64447).
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The Original Apple //c
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The original Apple //c is the oldest member of the //c family. It has
the following features:
o the 65C02 microprocessor
o 128K of RAM
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The UniDisk 3.5 Apple //c
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This is the Apple //c that introduced support for the UniDisk 3.5 drive.
It includes the following changes to the original Apple //c:
o the Protocol Converter, to support the UniDisk 3.5 external
disk drive
o a 256K IC to replace the 128K ROM
o some new serial port commands
o the Mini-Assembler
o two new Monitor commands (STEP and TRACE)
o built-in diagnostics
The UniDisk 3.5 Apple //c also includes improved interrupt handler
features and new external drive startup procedures.
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The Memory Expansion Apple //c
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The Apple //c that supports an optional memory expansion card
supports all of the features of the UniDisk 3.5 version. It includes
the following changes:
o an internal conncetor to support an optiona memory expansion
card.
o 4 64Kx4 RAM ICs to replace the 16 64Kx1 ICs
The Apple //c that supports the memory expansion option also recognizes
the I/O port ("slot") entry points in the firmware. The mouse, located
at port 4 in the original and UniDisk 3.5 versions, is now at port 7.
The memory expansion card uses port 4 in the new Apple //c. What this
means is that ALL THE MOUSE I/O ENTRY POINT ADDRESSES HAVE BEEN CHANGED
FROM $C4XX TO $C7XX.
All of this neat info, per verbatim the:
Apple //c Technical Reference Manual
(c)1986
'njoy
-C
And for those of you who are wondering which version I have, I
discovered mine to be the Unidisk version.
Hope this helps.
Scott