it could be done, then again, you could build the equivalent of a 33 mhz 68040 in ttl, you'd just need allot of time and space, a big fan and a very big power supply. it's just a matter of practicality. given that programmable logic chips are available with cheap or in some cases free software , that would be the way to go if you were really interested in trying to clone a swim chip. it might make a good project for an ee student, but you'd still have to reverse engineer the mac side of it (the drive side is pretty simple and somewhat documented) so it would probably be easier to just design a new widget that went into an expansion slot or had wire wrap wires soldered onto the key points of the logic board (or possibly a low profile clip over the 68k chip). i've actually considered building a small processor from discrete logic just for the experience, and that has been done both by industry and ee's/hobbyist (zen level master hobbyist that is!). i just have too many other things to do now.
on the other hand, the schematic from an ae hd + could be gotten without disassembly, though you'd have to hope all the chips have useful part numbers on them, and you just might be able to read any rom without taking it all apart, otherwise you'd have to want it bad enough to carefully desolder the rom without damaging it (not too hard if it's a dip, and still doable if it's surface mount), though of course you may still damage the board or the rom, and it might have a gate array, and by that time some of them had "security" features, though you can always record the signals while you exercise it. it would be a good project in reverse engineering, but as i've suggested, it's been my experience that most things can be reengineered more easily than reverse engineered (particularly later in time when higher tech parts are available than what the original used) if you have people clever enough to do the reverse engineering in the first place. that's true for most things at least, though i have seen one or two things that are easy enough to "enhance" without doing much reverse engineering (the really, really early cable boxes with a cabled remote being a prime example, it was all too easy to add any channel you wanted and turn the descrambling on and off, indeed the needed part could be had at radio shack for $10-$15, but that reflects mostly carelessness on the part of the equipment vendors and was corrected on most cable systems after several years (the remote cable plugged into the back very early on, making the signals very, very available!). not that i have any first hand experience of course, but i've seen the schematics.) Stuart Bell wrote: -------- > And before all that, the Woz Machine was implemented in TTL on the > controller boards for 5.25" drives on Apple IIs. I guess that the IWM > could be done in TTL; not sure about the SWIM. --------- -- The right of citizens to bear arms is just one guarantee against arbitrary government, one more safeguard against tyranny which now appears remote in America, but which historically has proved to be always possible." --Senator Hubert H. Humphrey. Here it comes again again <http://www.progressive.org/webex/wxmc042702.html><http://www.counterpunch.org/oden1.html> -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
