Specifications
-DHIVE SELECT 4
--*)(------3-2----~r~--1
-DRIVE SELECT 3
--*)f------3-0-----~~1t---li
-DRIVE SELECT 2
--l)~(
----:-:------I~+-I----+r---ll.
-DRIVE SELECT 1
--*-----------~-+-~:-----...----1
~~
~~
~~
en
Cl Cl Cl Cl
..
-----I
..
II
..
+5V
MS
OPTIONAL
SIDE SELECT
FROM DRIVE
SELECT
-...t--.
-MOTOR ON
ALTERNATE}
1/0 PINS
~
-MOTOR ON
2 2
--+)ff---
4
--
a
--::.=
=4-=
::.
=,~
~)(~---It-=
= =
==
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=~
:
6
___
6
___
J1
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______
., I
18
::
-1!~~---18
II
II
II
NOTE
If
the MOTOR ON line
is
multiplexed,
the
terminator
pack at
U9
must
be remov-
ed from each drive except
the
last on
the
line. The
current requirement is
the
+
24
Volt current
times
the
number
of
drives on
the
line
that
have MOTOR
ON
active.
FIGURE
7·8.
MOTOR
ON
WITHOUT
SELECTING
DRIVE
CIRCUIT
7.9
MOTOR
ON
BY
OPTIONAL
MOTOR
ON
AND
DRIVE
SELECT
39216·26
This option would be advantageous to
the
user who requires
one
drive to be selected at
all
times, but
does
not
wish
to
keep
the
motor
on
for
all
drives.
In
this configuration, the dc spindle motor
is
controlled from DRIVE SELECT
and
the optional MOTOR ON line.
The
advantage
of this option would be
that
the
output
control signals could be
monitored without spinning the diskette thereby extending
the
head
and
media life.
When
the
system requires
the
drive to perform a read
or
write,
the controller would activate
the
MOTOR ON line (pin 18) which
in
turn would
activate
the
spindle motor. After the MOTOR ON line
is
activated, a
165
ms delay must be introduced
or
the
TRUE READY line must be monitored before a
read
or
write operation can be performed.
To
install this option on a standard drive,
move
the shorting plug at trace MS to
the
MMO position. Figure
7-9
il-
lustrates the circuitry.
7.10
MOTOR
OFF
DELAY
This
jumper
option delays the spindle
motor
from turning off for
16
revolutions (2.6 seconds) after
the
DRIVE
SELECT
or
optional MOTOR ON signal goes false (high). This allows
the
user to be able to read
or
write within 1
p,s
after
the
drive has been reselected, thereby eliminating the motor start time. This option
is
advantageous
for
the
user
who
wishes to perform copy routines, but
does
not wish to use
the
optional MOTOR ON input signal.
To
enable
the
MOTOR OFF DELAY
on
the
standard drive, jumper trace MD.
7-8