Re: Kit-Based Lisa

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.

http://pdf1.alldatasheet.com/datasheet-pdf/view/8264/NSC/COP421.html

But start with the Lisa HWG - specifically the 1983 version.

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. Received on 2015-07-15 16:43:00