View Full Version : Just a C128 idea I was pondering...

February 1st, 2010, 01:07 AM
We all know that the C128 has the C64 built in, and the actual startup system is run by the Z80 in it. But I wonder...

If it has a C64 mode, is it possible, or even feasible to consider adding additional modes, such as the C16 and VIC-20 modes to it?

It's nothing I'm willing to undertake until I have enough duplicate systems to even attempt it (right now I only have one of each). But I'm curious if it's a possibility. I think it would be rather interesting to have all the entire series in one box.

Any thoughts on this? Or is it a pipe dream?

Keep in mind I'm only thinking about software and minor hardware compatibility (floppy, tape, modem, etc) not cartridges and other system-specific hindrances.

February 1st, 2010, 03:47 AM
The C128 is a C64 with more memory, an extra 80 column video chip, a Z80 and some more goodies. That means its 40 column mode is run by a VIC-II, its sound is a SID chip, its I/O is handled by two CIA's and so on.

The VIC-20 uses a VIC-I which does graphics and sound plus two VIA's. There were some VIC simulators on the C64, but those won't successfully duplicate the video or sound.

The C16 and Plus/4 use a TED chip which does graphics, sound and I believe a bit of I/O. Since it has 40 column video, rather simple sound and no sprites, I suppose a C64/128 could simulate it better than it can do a VIC-20. Yet the TED chip can produce a palette of 121 colours while the VIC-II natively only has 16 colours.

Now if you ask yourself if it would be possible to mount a VIC or C16 motherboard into a C128 case, that is a different task. Over the years people have dreamed about mounting a VIC and a C64 motherboards into a PC tower case and use an external keyboard. I'm not sure if anyone finished this kind of build, but it would be the closest thing I think.

February 1st, 2010, 09:39 AM
It was just something I was thinking about because the idea of having emulators (even some with hardware connection ability) I figured it would be plausible to at least link them together somehow (internally).

Of course, a secondary idea, since they are so radically different - yet similar - was a cartridge or other expansion module of some sort. But since you mentioned that above, having them remounted into another chassis, it brings up other possibilities...like a switchable subsystem, using the same I/O (for drives, etc - cartridges and such would still remain separate).

You have to admit, it would be dangerous, but if it could be done, wouldn't it be nice to have the entire series in one single box?

February 1st, 2010, 10:21 PM
That would be great, and even if the boards couldn't handle the same programs at the same time, they might be able to be in the same box (a C64 and a Vic 20) with switchable inputs/outputs.

The idea smacks of my little plan to make the C128 play Sega's Master System games with a converter of some kind (still thinking of it, haven't forgotten). I love the C= for some strange reason; any and all of them.


February 2nd, 2010, 12:05 AM
Same here. The idea of having a customized "all-in-one" computer never really left my head after all these years. Of course, being older and just a tad wiser, one realizes that several totally alien components don't coexist peacefully without some kind of...translation? conversion? Either way, it's something to tinker with. Perhaps even customize it in such a way that one no longer needs to buy ancient components such as drives, but only "slightly older" generic PC-type drives to install into a subsystem that already has the control system (from say, a 1571 or 1581) that's already in it.

Possibilities constantly bounce around in my head. Be interesting to team up with someone and actually get started on such an undertaking.

After all, I'd be willing to supply the computers to yank apart or cannibalize. heh