[Coco] 3.5" floppy cable

[Darren A]

On Tue, Nov 12, 2013 at 1:34 AM, Kip Koon wrote:

> Hi Darren!
> I've looked at the floppy connector pin out for floppy drives quite a bit.
> I don't understand why swapping the "Motor Enable Drive 0" signal on pin 10
> with the "Drive Select 1" signal on pin 12 will cause a floppy drive that
> functions normally as drive 1 function as Drive 0.



It sounds like you're looking at a pinout of the connector on a PC
motherboard (or a PC floppy cable) rather than that of a floppy drive.
 There are no "Motor Enable Drive 0" and "Motor Enable Drive 1" signals on
a standard floppy drive, just a single "Motor Enable" on pin 16.  Pins 10,
12 and 14 on a floppy drive are Drive Selects 0, 1 and 2 respectively
(Shugart Interface).

The twist in a standard PC cable swaps both the Drive Select and Motor
Enable signals which allows separate motor control for each drive.  Using a
CoCo disk system, all drive motors spin but only one drive is 'selected'.

Darren