C64 vs C64c
B. Slone
brian
Daniel Morrow
128/128d in c64 mode as I have never heard of any incompatibility
between the c64 and c64c (although the c64c does have a different
processor) and the only program for the c64 that doesn't work right on a
128/128d in c64 mode is a version of Rescue on Fractulous.
Cameron Kaiser
>Is the C64c 100% compatible with the C64? Software i mean.
Slightly incompatible if you're using a BN/E board, but only on really
obscure packages (SMON comes to mind). Other than that, yes -- I've heard
of nothing else that won't run on a 64C.
--
Cameron Kaiser * cdkaiser.cris@com * powered by eight bits * operating on faith
-- supporting the Commodore 64/128: http://computerworkshops.home.ml.org/ --
head moderator comp.binaries.cbm * cbm special forces unit $ea31 (tincsf)
personal page http://calvin.ptloma.edu/~spectre/ * "when in doubt, take a pawn"
Jason
> Is the C64c 100% compatible with the C64? Software i mean.
Well, apart from the sound differences (none of which will halt a
program, they just won't be the same) the only difference I'm aware of
is the early run of the C64c that doesn't appear to be able to do some
variations of Linecrunching and VSP. And that said, I've never *seen*
said machine but I'm told the game "Touchlight" was aborted because it
couldn't be fixed to work on it...
Pity really, it was a *bloody* good game...
--
Jason =-)
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David St. Hubbins
only one problem my moondust cartrige wont play the music on a c64c
B. Slone (bsl...@earthlink.net) wrote:
: Is the C64c 100% compatible with the C64? Software i mean.
:
: brian
:
:
Nicolas Welte
>
> "B. Slone" <bsl...@earthlink.net> writes:
>
> >Is the C64c 100% compatible with the C64? Software i mean.
>
> obscure packages (SMON comes to mind). Other than that, yes -- I've heard
> of nothing else that won't run on a 64C.
Hey, SMON isn't an obscure package. It's a very good ML monitor which
was published in early '85 by the German 64'er magazine. The only
problem with SMON on E-board machines is with the trace command. But
there's a fix available which just changes one CIA timer setting.
And this leads us to the real cause of the incompatiblity: Not the 8500
CPU, the 856x VIC-II or the 8580 SID and not even this 68pin PLA monster
are responsible. It's the good old 6526 CIA which gives the problems,
and it looks like a pure coincidence that all of those 'bad' CIAs were
used in E-boards. BTW, the 128DCR is also equipped with that CIA and
suffers from the same problem as all E-board C64. Early C64 with the
large boards and early C128s (flat and the plastic D model) did have the
old CIAs and worked fine with SMON.
My guess is that all 1987 and later CIAs are slightly different to the
older ones, but other than by the production date they can not be told
apart. It doesn't matter if it is a 6526 or a 6526A. In 1987 or '88 I
had to replace the CIA in my C64 and after that it would crash in the
'15 seconds copier' program. It was just the same CIA problem as with
the SMON and I could fix it after some time. But I never managed to fix
the brother program '17 seconds copier', which is just the 40track
version <:-)
Based on the knowledge that the CIA is responsible, it should be
possible to write a test program that tells you which CIA type is
installed. And the crash of SMON and the copier does not count as a
test!
Nicolas
Cameron Kaiser
>Hey, SMON isn't an obscure package.
Okay, okay, obscure on the other side of the pond. :-) When people say SMON
around here, everyone thinks SuperMON.
>It's a very good ML monitor which
>was published in early '85 by the German 64'er magazine. The only
>problem with SMON on E-board machines is with the trace command. But
>there's a fix available which just changes one CIA timer setting.
Which setting is that?
I know that some CIAs also have a flawed TOD. Possibly related?
Nicolas Welte
> >problem with SMON on E-board machines is with the trace command. But
> >there's a fix available which just changes one CIA timer setting.
>
> Which setting is that?
The change was just to load one of the timer registers with a larger
value than in the initial release. Don't remember if it was timer A or B
and how it is configured. I think I will look up the change and then
everyone can disassemble that part of SMON himself.
> I know that some CIAs also have a flawed TOD. Possibly related?
No, it was definitely not the TOD clock. It's time resolution is too bad
for being of any use for controlling a program. It only resolves 1/10 of
a second.
Nicolas
Cameron Kaiser
>> I know that some CIAs also have a flawed TOD. Possibly related?
>No, it was definitely not the TOD clock. It's time resolution is too bad
>for being of any use for controlling a program. It only resolves 1/10 of
>a second.
No, what I mean is, was the problem in the CIA also affecting the TOD? Since
you noted that it appears to need a timer value adjustment, a *possible*
check is to see how accurate the TOD is (versus what, of course :-).
Martin Brunner
>Is the C64c 100% compatible with the C64? Software i mean.
The C64c has another sound chip. Som, all digi-sounds are too quiet on
the C64c and won't sond well. You can fix by soldering a resistor to
the new SID (look at http://mjk.c64.org/). I tried this on my C128d
and this fix worked with every game, only Space Taxi was the
exception. It has still bad digi-sound.
Also the music wave forms are different, but the only game I played,
where the music sounds different is Impossible Mission II.
--
Martin Brunner (mbru...@forfree.at)
http://members.xoom.com/flexman/index.html
[Peugeot 404 - C64 Game Solutions - Selfmade Freeware]
Nicolas Welte
>
> Nicolas Welte <we...@chemie.uni-konstanz.de> writes:
>
> >> I know that some CIAs also have a flawed TOD. Possibly related?
>
> >No, it was definitely not the TOD clock. It's time resolution is too bad
> >for being of any use for controlling a program. It only resolves 1/10 of
> >a second.
>
> No, what I mean is, was the problem in the CIA also affecting the TOD? Since
> you noted that it appears to need a timer value adjustment, a *possible*
> check is to see how accurate the TOD is (versus what, of course :-).
You can always run a loop for some time and then calculate how many
cycles it takes and measure the timer or TOD against that standard.
But I'm still in doubt that this TOD clock problem is related. I got the
impression that this TOD flaw only appeared in a small batch of
manufactured CIA chips, but this timer issue I mentioned seems to be
built into all 6526 CIAs manufactured since 1987. I never had a 8521
CIA, maybe these are different? I guess I could check that with the 8520
I have. Might even be a test for this TOD clock stuff, because the 8520
doesn't have the TOD clock at all! And if it is not there, it can't be
responsible for the inaccuracy or whatever of another timer ;-)
Nicolas
StukaBlitz
sid sounds better but that could be bad chip on the 64cs part
Clint Woodworth
Stuka...@aol.com
Nicolas Welte
>
> I have a 64 and a 64 c and the colors on the older 64 seem more sharp and the
> sid sounds better but that could be bad chip on the 64cs part
The C64C with the small rev E board has a different video chip (856x
series), and it is worse than the latest models from the 656x series.
Most noticeable are vertical stripes in the picture and bright sparks
which occur from time to time (especially in demo programs with heavy
usage of VIC tricks). Unfortunately all C128 models also suffer from
this new technology.
Nicolas
StukaBlitz
individual 64c I have.
Clint Woodworth
Stuka...@aol.com
Oliver Klee
Indeed, the picture is sharper and the colours are a bit pale.
The bright sparcs occur when a colour register is written whilst being
displayed (e.g. changing the border colour in $D020 when the raster
beam is in the border). This is very nasty for demos that are
programmed on a C64 with the old VIC.
There are two different kinds of vertical stripes, those occuring at
each clock cycle and those occuring in the middle between two cycle
(each cycle correspond to the width of 1 char displayed).
I don't know the exact reasons for the stripes, but they may have
something to do with memory access by the CPU and the VIC.
I remember one kind of stripes disappearing on a C128 if switched to
2MHz mode.
--
/\ Odi/Smash Designs - musician, journalist and programmer.
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