Faster/wider CPU...

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Dave
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Faster/wider CPU...

Post by Dave »

I know that Gold Cards, etc use much trickery to make a 68020or 68040 forget who they are and pretend to be a 68000.However, there are faster 68000 and 68008 processors that should easily interface with the existing design without the great trickery of the Gold Card designs...

Does anyone have any thoughts or knowledge on this?


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Dave
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Re: Faster/wider CPU...

Post by Dave »

To clarify, I'm looking at the 68EC000. I like the idea of a 16MB QL, and there's a faster 10 MHz part as well as the 8 MHz part. Can of worms, I know, I know... :)


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Re: Faster/wider CPU...

Post by Zerover »

I think the one you want is the MC68HC001, which is 8-bit compatible. It can address 16MiB and runs up to 16MHz.


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Re: Faster/wider CPU...

Post by Dave »

The EC and HC variants both do that. I can, however, obtain EC variants for less than half the cost of a similarly clocked HC.

I'm curious if there's a simple way to have a faster CPU than the 7.5MHz of the 68008, and/or if there's a simple way to have wider memory accesses, and still use the onboard facilities, like the gold cards do, but without lots of heavyweight custom logic.

I am looking at whatever comes out of this thread being an open-source design.


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Re: Faster/wider CPU...

Post by Dave »

A few people (okay, two!) have asked me what I'm doing...

I have a 68EC000 chip accessing 2MB of RAM, booting JS ROMS and producing the corrupted output of an otherwise successful boot. I'm working on resolving the video issue, and getting the keyboard side up (hello 8049 and friends!)... but I have no plans to get microdrives, serial or joystick ports working at this time. I do want it to take standard expansions so I can use a floppy disk interface, etc.

It's just personal exploring at this stage, but if anything comes of it, I'll share.

Photos to come.


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Dave
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Re: Faster/wider CPU...

Post by Dave »

I can get 68EC000FN16 for $4 each.


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Re: Faster/wider CPU...

Post by twellys »

Now I'm a contractor, I'm starting a FPGA that interfaces to a 68020...

... and yes, their service life is 30 years.

Now, how old is the QL? ;)


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Re: Faster/wider CPU...

Post by Dave »

Here's my thing: I want to "do something" and I don't know how to work with FPGAs. I'll sit here and play with what I 'sort of' know. It is only playing, after all...

If I could team up with people (even given my limited skills) and contribute towards some kind of new machine, I'd be ecstatic, but it doesn't seem very likely to happen...

I'm very open-minded.


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Re: Faster/wider CPU...

Post by Dave »

And there's the catch :) I can't program worth a damn anymore. I tried :) Just never got it back. However, the PCB design aspect,that's all still inside my head, so that's something I can do.

I looked at FPGAs, but there's so much foundation knowledge I don't have, and I don't know enough to know what's missing.

Combine that with re-using QL custom logic (easy) vs. recreating it (hard)...

Would you like to do a custom QL-on-a-chip for us? If you did, you'd gain amazing street-cred. That said, I know someone has been working on one for several years and as of their last public update it gets to the F1/F2 screen and no further.

A bunch of skilled people like you and well-intentioned people like me should get together and make something cool happen.


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Re: Faster/wider CPU...

Post by Dave »

The thing I have been playing with is very modular - everything is a daughter card, so the video system, floppy interface, memory, serial ports etc are separated out to their own daughter cards.

This way, if someone wants to put in a fast original CPU or modern equivalent, they're free to.

That said, I see the attraction of a small cut-down redesigned "Issue 8" QL PCB, even if it is not very practical.


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