[Coco] Floppies to PC or other OSs

[Phill Harvey-Smith]

On 14/02/2013 22:40, Frank Swygert wrote:
> Those should be CoCo compatible -- at least with a proper CoCo DECB
> chip. They look to be new manufacture, or are they new old stock? If
>  they are new, where did you get them?

They are new controllers made with surface mount LS parts but IIRC
otherwise identical to a classic Dragon Dos controller.

> I wonder if the 2797 is HD compatible, or if a HD compatible chip
> could be used in a CoCo controller? Would be nice since HD drives are
> the only easy ones to find now. DECB couldn't use the full capacity,
> but OS-9 could. You have to admit, even just using a fraction of the
> full capacity is better than no disk at all!

Yep the 2797 is compatible with HD if you switch it to 8" mode and 
supply it with a 2MHz clock, I experimented with this with an original 
DDos, though as noted I had to run in fast mode to keep up with the data 
rate. But that wouldn't be a problem on a CoCo 3 as the default is the 
1.7MHz speed.

On a CoCo 1, 2 or Dragon you have to use AD mode which means that the 
code has to run out of rom and be in the top 32K. This isn't a problem 
for Dragon dos or DECB but would make an OS/9 driver a little tricky :)

I may even have a version of DECB that I targeted at the 2797 somewhere, 
I seem to remember it was mostly just a matter of the 2797's status 
codes being slightly different as it does side selection internally and 
has a side select output that the 1793 does not. If you used a 2793 that 
is completely software compatible.

Cheers.

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.