Apple IIc Models and ROM numbers

[omn...@iinet.net.au]

So far as I can gather there were 3 model numbers ...A2S4000, A2S4100 & the A2S4500, the last being for the plus version.

What was the turning point from the 000 to the 100 model do we know? ROM255 was obviously the 000, and the ROM 0 version also?? Im guessing that the memory expansion capable version was the 100 model but cant substantiate this. Anyone?

Why I'm asking is Ive seen a mother board out there with a 132-0033-B MON chip, and I'm figuring this was when they removed support for the AppleTalk device that was cancelled. Still a ROM 0, but the latter version of it.

Just wondering if anyone knows.

[Eric Rucker]

The versions of //c by ROM revision, and a quick summary of what
changed (get ROM revision by doing PRINT PEEK(64447)):

ROM 255: A2S4000, 1984-04 to 1985-11, units after 1984-11 had a serial
port timing fix (74LS161 replaced with oscillator on production line).
Slot allocations are: 1, 2: SSC, 3: 80 col, 4: mouse, 5: easter egg, 6:
5.25" controller, 7: firmware to boot slot 6, drive 2
ROM 0: A2S4000, 1985-11 to 1986-09. Easter egg moved to slot 1 (causes
some annoying problems when trying to actually use the printer port for
input), SmartPort firmware in slot 5, S6D2 firmware removed,
unused AppleTalk firmware in slot 7
ROM 3: A2S4100 (but can be installed in A2S4000), 1986-09 to 1988-01.
New motherboard with memory expansion connector, new keyboard. RAM card
firmware in slot 4, vestigal AppleTalk firmware removed, mouse firmware
in slot 7.
ROM 4: A2S4100 (but can be installed in A2S4000), 1988-01 to 1988-08.
Improvement in RAM card firmware behavior when no additional RAM is
installed, fixes for keyboard buffering bugs introduced in ROM 3 (due to
screen hole allocations changing)
ROM 5: A2S4500, 1988-09 to 1990-11. New keyboard layout, 3.5" drive in
case instead of 5.25", 4 MHz accelerator on motherboard. Firmware
changes to support accelerator.

--
Eric Rucker - http://bhtooefr.org - bhto...@bhtooefr.org

[omn...@iinet.net.au]

ROM 255: A2S4000, 1984-04 to 1985-11

This is MON Chip 342-0272

ROM 0: A2S4000, 1985-11 to 1986-09.

This is MON Chip 342-0033-A..........so where does the -0033-B fit in?????

ROM 3: A2S4100 (but can be installed in A2S4000), 1986-09 to 1988-01.

This is MON Chip 342-0445-A

ROM 4: A2S4100 (but can be installed in A2S4000), 1988-01 to 1988-08.

This is MON Chip 342-0445-B

ROM 5: A2S4500, 1988-09 to 1990-11.

Have yet to get the MON Chip number for this one.

[omn...@iinet.net.au]

Okay...got the ROM 5

342-0625-A

Now just the 342-0033-A and B difference.

[Eric Rucker]

omn...@iinet.net.au wrote:
> Now just the 342-0033-A and B difference.

I recall having a ROM 0 //c with a EPROM - the difference might just be
EPROM vs. mask ROM.

[Hugh Hood]

in article ku5g4k$bom$1...@dont-email.me, Eric Rucker at bhto...@bhtooefr.org
wrote on 8/10/13 8:44 AM:

>
> The versions of //c by ROM revision, and a quick summary of what
> changed (get ROM revision by doing PRINT PEEK(64447)):
>

> ROM 0: A2S4000, 1985-11 to 1986-09. Easter egg moved to slot 1 (causes
> some annoying problems when trying to actually use the printer port for
> input),

Eric:

Thanks for posting the great info on the IIc ROM revisions, I think.

Just when I feel confident that I'm finally getting a grasp on all the
anomalies associated with the IIc serial ports, you reveal another about
which I was totally clueless.

Heck, this little 'feature' stayed with the machine up to and including the
IIc+, which I confirmed this morning with this little one liner:

From BASIC:

1000 IN#1 : INPUT A$ : PRINT A$

RUN

Rich Williams Ernie Beernick Mike Askins James Huston


Do you know if this 'feature' is confined to input from BASIC programs, or
does it also infect input from machine language programs?

I hoping for the former, but fear the latter.

Thanks again. Really good info.






Hugh Hood

[Bill Garber]

"Eric Rucker" <bhto...@bhtooefr.org> wrote in
message news:ku83rk$ao7$1...@dont-email.me...

More than likely, the -B would just be the -A
with a bug fix, similar to the 445 -A and -B.
They might have called it a ROM 1, but didn't.
It's hard to tell with Apple's naming convention.

Bill Garber
http://www.sepa-electronics.com

[Eric Rucker]

Bill Garber <will...@comcast.net> wrote:
> More than likely, the -B would just be the -A
> with a bug fix, similar to the 445 -A and -B.
> They might have called it a ROM 1, but didn't.
> It's hard to tell with Apple's naming convention.

Well, one way to find out.

Just checked ReactiveMicro's dump of 342-0033-A (was going to dump my
own - and looks like my EPROM vs. mask ROM idea was wrong, as mine is
mask - now I'm wondering what's in my dead ROM 0) but couldn't quickly
find the right way to do so)...

MD5 (Apple IIc MON $00 - 342-0033-A - 27256.bin) =
e0d67bb1aabe2030547b4cbdf3905b60

Anyone got a 342-0033-B ROM, and a good way to dump it?

[omn...@iinet.net.au]

Can you direct me to a good EPROM reader and burner? I have a 0033-B chip on the way and seeming I'm getting into all this, I may as well get one!

[Bill Garber]

<omn...@iinet.net.au> wrote in message news:9a4ea3
ef-6c90-4001-95...@googlegroups.com...

> Can you direct me to a good EPROM reader and burner?
> I have a 0033-B chip on the way and seeming I'm
> getting into all this, I may as well get one!

http://www.mcumall.com/comersus/store/comersus_dynamicIndex.asp

I have the GQ-4X. It does everything I need it for,
and more. Plus it's USB, so no parallel port needed.

Bill Garber
http://www.sepa-electronics.com

[omn...@iinet.net.au]

Ok, further to the 342-0033-B saga, Ive come across the briefest mention of it. It would seem to still be a ROM 0, but 3 brief words followed it.....ImageWriter II Firmware. So until we can do a compare of the A and B versions, this is the best I could dig up.

And along with another unconfirmed titbit....

Apple IIc's with a serial number higher then F6051FGA but still with the A2S4000 model number, are able to run the UniDisk drive, those before, no. Now wether they are still reporting themselves as ROM 255's I've no idea as I cant test this as yet myself.

The hunt continues.

[Eric Rucker]

omn...@iinet.net.au wrote:
> Apple IIc's with a serial number higher then F6051FGA but still with the A2S4000 model number, are able to run the UniDisk drive, those before, no. Now wether they are still reporting themselves as ROM 255's I've no idea as I cant test this as yet myself.

I would expect that serial number (which is actually F6051GFA, per
http://support.apple.com/kb/TA27890) to be the ROM 0 changeover, as that
was the entire reason for ROM 0's existence.

[omn...@iinet.net.au]

What struck me most was the fact that such a significant ROM change, and I don't mean difficulty wise, but capability wise, yet no model number change. Using up the last cases? I know it's all rather bland really, but I'm enjoying the chase.

[Eric Rucker]

omn...@iinet.net.au wrote:
> What struck me most was the fact that such a significant ROM change, and I don't mean difficulty wise, but capability wise, yet no model number change. Using up the last cases? I know it's all rather bland really, but I'm enjoying the chase.

It was the same hardware, though, and the older revision could be
upgraded.

Similarly, the IIGS didn't change model numbers from A2S6000 to A2S6100
until the ROM 3 (which was a different motherboard).

[omn...@iinet.net.au]

True, and I have seen some apple service notes mentioning all the newer ROMs, not including the IIc Plus 5, could be fitted to the oldest IIc MB, regardless of the memory expansion slots existence.