Powerbook 500 Series Developer Note

[Paralel]

I was looking through the Powerbook 500 series developer note:

http://tech-insider.org/mac/research/acrobat/9405-a.pdf

And thought it was interesting that the PDS slot was originally designed to allow for processor upgrades. Considering the Rev C. card cage actually contains a 68000 processor to translate PC card commands into commands that make sense for the '030 bus used in the 500 series, I can see how this would be possible. There really isn't much of a difference between the processor daughterboard connection and the PDS slot, they are both just meant as interfaces to the main '030 bus.

What do you guys think, is it possible to upgrade the processor through the PDS slot (even though it mentions that this function isn't enabled) on the 500 series? Or is it possible to make further use of the PDS slot than how it was used [implement a CardBus slot rather than just simple PCMCIA, etc...] Anything that can run on a '030 bus should be possible to implement, right? I have read that Sonnet successfully used it to add a 68882 FPU upgrade to the PB 500 series (although I will admit, I have never even seen a picture of one, so, while it is mentioned in more than one place, it's hard to say if this particular upgrade ever actually existed)

 

[Elfen]

There was a 603ePPC Upgrade for the 500 series, but I do not know of that was a logic board upgrade or a processor swap. I believe it was a CPU Card swap. 

Now this got me thinking. The 1400 CPUs are on a card as well, as well as the ROMs, I believe. As are other CPUs on a card, also contain their on ROMS. The problem where is being the compatibility of the 1400CU Card to the CPU Card connector on the 500 Motherboard. If it fits and is compatible, it could solve a lot of problems with the PCMCIA Booting on the 540. But would it accept the way the 500 has their PCMCIA set up? In the 1400, the PCMCIA is tied to the CPU through a buffering chip, not a through translator.

Again, it depends of it fits and if it is compatible. Unfortunately, the 190/5300/2300 has their CPUs on the motherboard. and not on a card. If it were on a card, I would think it would be ore compatible with the 500 series. Alas it never happened that way. This would undertake a lot of research before applying such a theory to work. And if it does work, it would no longer be a 500 series, but a 1400 series in a 500 series case.

 

[Paralel]

Any type of PowerPC processor is of no interest to me. I'm strictly 68k.

 

[Elfen]

That is understandable, as I can see the 68K being the better processor in a lot o things both Mac and non-Mac Related.

This leaves a big hole in what can be done with what was done. But I'm most certain that you can interface a 68851/2 to the 680LC40 on the 540c either directly or indirectly.