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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Dr_Righteous on May 20, 2003, 04:50:46 PM
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I was looking over the pinouts for the 68040 and 68060 and discovered that they're nearly identical... There are a couple differences, but I'm not sure they really matter.
Has anyone out there tried taking an A3640 card, changing out the regulator to make it 3.3v... Changing out the occilator for 50MHz... Cutting off the center pins of the 68060 and seeing if the system worked?
Obviously you'd lose the advantage of added memory and a few new features... But you'd end up with an upgrade far cheaper than a Cyberstorm MK3 if it worked.
Any thoughts?
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One thing to remember is that the 68060 doesn't use a double clock for anything. A 25MHz 68040 is run from a 50MHz clock in 100% of the cases I've seen. A 50MHz 68060 is run from a 50MHz clock. There's one pin for bclk and one for pclk (unless my memory is wrong, I have looked at a 68k cpu for 2 years now), on the 040 these are different but 060 the same. I think :-)
Except for this there's a couple of odd differences I don't remember at the moment. Anyway, it is doable, because Motorola made 040-060 upgrade kits which only had a PGA to PGA converter with a voltage regulator on it. Everything else was done by rewiring...
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Just found it:
The 68060 has an extra bus arbitration pin, BTT. This is not present in earlier devices. It is used for the 68060 high-speed modes. It must be pulled high with a resistor so it won't be used. It's a bi-directional pin, so the chip will see the pull-up and not use it.
Basically, I guess this means the chip would be more effective with specialized glue logic, but I don't really think any 68060 accelerator for Amiga uses this arbitration mode anyway...
Good luck :-)
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Yes, the occilator on the card is a 50MHz one... But the question is where is the halving taking place? If it's occuring before the pCLK pin, then it's being driven with 25MHz... In which case I'll have to change out my occilator with a 100MHz one.
Either way, I'm working on an adapter board to just plug the 68060 into the 68040 socket... Adding of course the extra power and ground connectors, and high/low pulls to the other pins. Should make for an interesting project!
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oh please let it work, if it does.. drop a "extensive" thingy in here, so we all may gaze in admiral.. and offcourse, i will steall all your work of the pages, and go find me a cheap second handed card somewhere to try it on...
Best off luck!
B!
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Actually, I'm working on the schematic for a processor adapter board... One that'll plug directly into the CPU socket (just like the Sonnet Quaddoubler). It'll be publicly released because I'm all about the community :-D
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Thinking about doing the same thing...Any luck so far?
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If it works then count me in, even if it has been 1,5 year ago since those postings !! I´m still interested. Still don´t have a Cyberstorm, only two A3640´s !! :-)
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At $296 I don´t think many people are interested, considering you have to buy the 060 as well... :-)
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oh indeed but he has asked, i've answered :-)
The URL was only for reference pourpose.
BTW . . .have you an idea how much it could costs a project like that?
-1 PGA socket for the 060
-1 PGA socket for the 040
- 1 voltage regulator
PCB- Logic-project and bla, bla . . .
Its not so overprized as you think . . . and even if you can find the sockets at a human price in small batches ;-)
Happy XMas
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Won´t it be easier to overclock a 68060 from 50 Mhz to 100 Mhz ???
Damn, I wished it were easier with that 3640 project ... :-)