Re: Kit-Based Lisa

From: Kevin Keith <krfkeith_at_email.domain.hidden>
Date: Tue, 18 Mar 2008 13:38:38 -0700 (PDT)

OK! Thanks for the help!

On Mar 18, 3:11 pm, Ray Arachelian <r..._at_email.domain.hidden> wrote:
> Kevin Keith wrote:
> > The only parts that won't be like the real Lisa is the floppy drive
> > and the video.  Other than that, it will be exactly the same.  Unless
> > someone here knows where I can find a GCR floppy drive, I think this
> > makes the most sense.  Also, does anyone know if the technical
> > documents for that COP421 is?
> I don't know enough about the real COP421 to answer that, however both
> the set of functions of the GCR floppy and how the 68K sees the COP421
> are documented in the Lisa Hardware Guide.  Also, the Lisa schematics.  
> So start there.
> The HWG has full documentation on the 6504 floppy.  You could build a
> circuit that does the same kind of thing.  If you can figure out how to
> adapt a 1.44 floppy drive to encode GCR, and you probably could - for
> example the CatWeasel controller allows for Macintosh floppies to be
> read by a PC controller and takes care of the multi-speed translations,
> you could even get GCR compatibility.  You might want to add a solenoid
> and mechanism to push the eject button and you'll have the auto-eject.  
> You'll also want to look at Inisde Mac for Sony 400K details as the 1983
> HWG refers to the twiggy drives.
> If you do go with a full COP421 - say you find the way to dump the code
> inside one and say you can find all of its documentation, you'll still
> need at that point to either build an interface to the mouse and
> keyboards you wish to use.  So it's probably best to ignore that path,
> and build something that behaves the same way as the 68K expects the
> COP421 to behave.
> Of course having a copy of the actual COP421 code will help far more.
> But start with the Lisa HWG - specifically the 1983 version.
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