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

[David Hazelton]

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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