[Coco] Coco 3 high-density floppy controller/IDE interface

[Chuck Youse]

For those who are interested, I threw together a web page.  Web designer
I am not, and one section needs to be filled in (the programming
details), but this should be enough to satisfy at least any initial
curiosity:

http://www.serialtechnologies.com/coco/fdc/index.html



On Thu, 2008-07-03 at 21:57 -0400, David Hazelton wrote:
> AS my Floppy controller has been dead for a few years, I'm interested in 
> the final product.  I could test it out, but since I haven't had my coco 
> running for a few years, due to my B&B controller needed a floppy boot 
> to load OS9.  I'm not sure I can debug any of it.
> 
> David Hazelton
> 
> 
> 
> Chuck Youse wrote:
> > Hi folks,
> >
> > I recently designed and built some PCBs built around the 82077AA-1 for
> > the Coco 3 - it's a floppy controller for DD/HD disks (so it supports
> > your standard 1.44MB 3.5" floppy).  Since I had the room I also threw on
> > an 8-bit IDE interface (typical waste-half-the-sector design).  
> >
> > I'm still cranking on the software to verify operation (and that the
> > Coco can keep up with the 14us data rate) but so far all signs are good.
> > Ultimately it should work nicely as a high-density, no-halt controller
> > for OS-9, if the software is properly tweaked - the 82077AA has a
> > 16-byte FIFO that should eliminate the HALT/NMI hack of the Radio Shack
> > design, if the Coco is running at 1.78MHz.
> >
> > As it's meant to take the place of a standard RS disk controller, it
> > also has the 8K EEPROM 28-DIP socket on it for Disk Basic (or whatever).
> >
> > I personally don't use RS-DOS, so I had no intention of patching Disk
> > Basic -- my ROM will simply allow automated booting either from floppy
> > or an attached IDE disk.  Also, I don't really plan on supporting
> > multiple drives, as there's little need for more than one floppy drive
> > when you've got a hard disk... but the controller itself actually will
> > support two drives on an PC-style twisted cable.
> >
> > Anyway, I've got an extra board or two (and schematics, etc.) if anyone
> > wants one for development purposes, either to patch Disk Basic or get in
> > on the no-halt OS-9 driver action.  At some point I may offer them for
> > sale a la Cloud-9, but I doubt there's really enough interest for that..
> >
> > C.
> >
> >
> >
> >
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> >
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> 
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