[Coco] again 3.5" drive

[Jim Hickle]

The CoCo floppy controller and floppy drives
 use pins 10 thru 16 for these signals (odd numbered
lines are grounded):
10 - Drive Select 0
12 - Drive Select 1
14 - Drive Select 2
16 - Motor On

Each drive is jumpered as 0,1 or 2.
Line 16 turns on motors of all drives.


PC controllers are different:
10 - Drive 0 Motor On
12 - Drive Select 1
14 - Drive Select 0
16 - Drive 1 Motor On

ALL drives (all two of 'em) are jumpered as Drive 1.
Cable lines 10 thru 16 are twisted for Drive 0
(remember it is jumpered as Drive 1).  Since these
lines have been reversed, the drive still gets 
Drive Select on line 12 and Motor On on line 16.

If you use a PC cable on a CoCo, drives on the
controller side of the twist will behave normally.
I haven't tried it, but I assume that a drive jumpered
as Drive 2 would respond to commands for Drive 0 at
the CoCo.


--- John T Chasteen <johnchasteen.2 at juno.com> wrote:

> Jim You are up early. Please discuss more detail on
> twisting 10 thru 16
> Thanks
> John 
> On Thu, 24 Apr 2008 05:44:20 -0700 (PDT) Jim Hickle
> <jlhickle at yahoo.com>
> writes:
> > 
> > 
> > Diego Barizo <diegoba at adinet.com.uy> wrote: This
> time it worked 
> > out.
> > I twisted the wires and now it's drive 0
> > Weird. I could have sworn that I tried using a PC
> cable with the 
> > twisted 
> > wires and didn't work...
> > >> 
> > Different lines are flipped on the PC: PC floppy
> cables twist lines 
> > 10 thru 16.
> > 



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