13 Mar
2005
13 Mar
'05
8:45 p.m.
From: "Pete Turnbull" <pete at dunnington.u-net.com>
Sent: Friday, March 11, 2005 3:38 PM
On Mar 11 2005, 12:44, Randy McLaughlin wrote:
I have tried to research the issue further but can I find no authoritative
references to pin 2 being anything but an RPM select line.
Other websites like mine do claim it is use for write current but provide no
references to show it.
If anyone has an authoritative reference stating it was not used to select
rotational speed I will be happy to change my website stating that it does
have multiple uses.
Until then I have changed my site to say other sites state otherwise but
include hyper-links to the manufacturer docs stating that it is for two
speed drives (ala early IBM AT).
Please note I am not looking for what people remember it does but actual
documents from a manufacturer. I tested it with a TEAC FD-55GFR and sure
enough it slowed the RPM when grounded.
Randy
www.s100-manuals.com
From: "Michael Sokolov" <msokolov at
ivan.harhan.org>
> Changing the RPM is an option on SOME
drives, and for PeeCees to
work it
> must be OFF. It is very useful for Classic
Computers, though.
>
> The high density select signal (pin 2) may or may not switch RPM,
but it
> always switches the write current.
No, I have refered to the TEAC site and to WDC:
WDC referes to pin 2 as speed select, their controller can be used
with
either single speed or dual speed 1.2mb drives:
http://www.wdc.com/en/library/legacy/controllerboards/1006mm1.pdf
Michael is correct, the exact function varies from drive to drive, and
it always involves changing the write current. Some drives have
several jumpers to affect this. I could show you several from my
collection like that. Some controllers work at two speeds, some at two
data rates. Some of the WD controllers can be configured either way.
--
Pete Peter Turnbull
Network Manager
University of York