Floppy drive pin 2 question?
cctalk at randy482.com
Thu Mar 10 16:29:31 CST 2005
From: "Jules Richardson" <julesrichardsonuk at yahoo.co.uk>
Sent: Thursday, March 10, 2005 2:33 PM
> Just futzing around with this Manta board (SCSI floppy controller).
> The docs I have say that pin 2 of the floppy connector is normally an
> input to the controller from the drive, but that some drives expect pin
> 2 to be an output to the drive from the controller (e.g. for changing
> rotation speed on a drive capable of 300 and 360rpm)
> That sounds wrong to me; surely most drives either don't use pin 2 for
> anything, or they expect it to be an output from the controller (to cope
> with things like speed changes)
> What drives use it as a signal driven by the drive, and what for?
> I'm tempted to ignore the docs I have and configure it as an output from
> the controller - I'd just rather not blow up a drive or controller
> board :-)
I have a webpage describing disks and disk drives.
Pin 2 on a 34 pin floppy connector is a little used pin. It was used to
change the RPM on some 5.25" 1.2mb drives.
It changed the RPM from 360 RPM (pin 2 high) to 300 RPM (pin 2 low). This
was supposed to make it easier to read/write DD disks in a HD drive.
Only early AT controllers needed it, later controllers kept this pin high
and used an odd transfer rate.
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