Path: utzoo!attcan!uunet!cbmvax!daveh From: daveh@cbmvax.UUCP (Dave Haynie) Newsgroups: comp.sys.amiga.tech Subject: Re: 32-bit LUCAS memory board Message-ID: <5338@cbmvax.UUCP> Date: 28 Nov 88 22:44:26 GMT References: <5322@cbmvax.UUCP> Organization: Commodore Technology, West Chester, PA Lines: 46 in article <5322@cbmvax.UUCP>, ditto@cbmvax.UUCP (Michael "Ford" Ditto) says: > Keywords: kickstart hardware hack > Summary: 32-bit kickstart: Two roms? > In article <1988Nov23.104910.15213@gpu.utcs.toronto.edu> anakin@gpu.utcs.UUCP (Anakin Research) writes: >> I would like to move the kickstart area into this 32-bit wide path. > How about this: The user buys *two* copies of the ROM from Commodore; you > have one hooked to the "high" side of the 32-bit data bus, the other to the > "low" side, with one chip's A1 tied high, the other low. Half of each chip > would be unused, but it sure sounds legal! (This is not to imply that anyone > should take my legal opinion seriously!) Perhaps someone who's looked at > the '020 bus spec more recently than I could confirm that it would work... That would work, assuming you didn't drive them too fast. They probably can go faster than the 68000/7MHz, but I'd have to check the specs to see what the limit is. >> I understand that many of you would like to have an MMU. > From what I remember about the '851, it's probably "too late" (i.e. you > would have wanted to design that in when you did the memory & 68000 bus > interfaces). It basically has to go "between" the '020 and the memory. That's true. Same kind of things apply to an external cache. Not much you can do with existing LUCAS boards to get the MMU in place. It would be pretty simple to relayout the LUCAS board for a 68030, and it's a heck of alot easier than redesigning it for a 68020 + 68851. Neither of which solve today's problems... > As for Unix compatibility, nobody else knows how to make that work either, > since we haven't documented what is needed (basically some software setup > that's done in the ROMs on the 2620). We also haven't announced whether > or not we are going to document it, but I hope we will. Me too. At the moment, the only way you could run Unix would be to leave a place that would accept the A2620 ROMs, and you'd have to clone some of the A2620 registers as well. No small task. Hopefully a better solution will be available, if we do provide documentation at a later date. In any case, you won't have Unix without an MMU. > -=] Ford [=- -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy Amiga -- It's not just a job, it's an obsession