14 Mar
2005
14 Mar
'05
12:30 p.m.
From: "Randy McLaughlin" <cctalk at randy482.com>
Sent: Monday, March 14, 2005 1:29 PM
<snip>
You have mis-read the table.
Pin 2 can only change the speed to 300 RPM by lowering pin 2, with pin 2
high no matter what the drive runs at 360 RPM.
The density mode can be high with pin 2 high or low with pin 2 high
depending on jumpering.
The one and only standard the document gives for pin 2 is speed change.
All of the original AT controllers required two speed drives. Later
controllers added the 300K transfers.
Randy
www.s100-manuals.com
Randy
www.s100-manuals.com
I have now found references to more controllers/drives using pin 2 in a
variety of ways.
One controller seems to say it best calling pin 2 a general purpose
controller pin.
2.88 mb controllers use it one way, some 1.44mb drives use it another, some
5.25" drives use it for one thing other another.
I'll work up a description that warns people to carefully check the
references for the drive controller pair to make sure any and all pins not
defined by the SA400 are used the same for both.
The only two pins not described in the SA400 standard that seems to have
global acceptance are the 4th drive select and side select.
Randy
www.s100-manuals.com