a CIA riddle - please run these tests

From: groepaz_at_gmx.net
Date: Thu, 18 Jun 2020 19:37:54 +0200
Message-ID: <9391920.tdPhlSkOF2_at_rakete>
Howdy Hackers!

While debugging a certain thing in VICE [1] we discovered a strange thing
which doesnt quite match what we thought we knew about the CIAs. Perhaps there
is actually a 3rd kind of CIA in the mix :) We need a couple people to run a
few test programs [2] and report the results to find out what we are really
looking at.

Please first note down:
- what machine are you testing (c64/c128)
- what ASSY is it (ASSY number on the motherboard)
- what CIAs are on the board. write down ALL markings (eg: MOS 6526 / 1888
216A)

Now run the "delay2-new" and "delay2-old" programs. Green border means "test
passed", and will generally tell if you have a "new" or "old" CIA. (Contrary
to popular belief this can NOT be reliably determined from whats written on
the chip)

After that, run the other programs.

4.prg 5.prg 6.prg should pass on any type of CIA (green border means passed)
*-new.prg should pass on "new" CIA and fail on "old" CIA
*-old.prg should pass on "old" CIA and fail on "new" CIA

To confirm the above, make sure to really run ALL programs and please tell
which fail and which do not. Especially interesting are results that are
different from the above expected behaviour. Also interesting are tests done
on C128D and/or using a CIA with timestamp 4485 as William used in that bug
report.

Thanks!

[1] Bug report: https://sourceforge.net/p/vice-emu/bugs/1219/
[2] Test programs: https://sourceforge.net/p/vice-emu/bugs/_discuss/thread/
538e31942f/ba33/attachment/cia-shiftregister-tests.zip


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Received on 2020-06-18 20:02:55

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