Table of Contents
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Ground
1
3 5 7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
l 1
43
45
47
49
Write commands. When the signal logic level
is false (high), the input control l i nes and the
output status lines are disabled,
The Drive Select address is determined by a
select shunt on the circuit board. Drive Select
lines 1 through 4 provide a means of daisy
chaining a maximum of four drives to a con-
t roller. Only one can be t r u e ( l ow) at a t i m e .
An undefined operation mi ght r esult if t w o or
more drives are assigned the same address or
i f tw o or m o r e D r i v e S elect l i nes are i n t h e
t rue
( l o w ) s t a t e s i m u l t a n eously. A
S elect l in e m u s t r e m a i n s t a bl e i n t h e t r u e
(low) st at e u n t i l a n y o p e r a t ion i n p r o g r ess
(Step, Read/Write) is completed.
U sing S id e
S e lect o p t i on s 1 8 t h r o u g h 4 8 ,
Drive Select lines may be used as Side Select
lines for the TM848-2E (see Section 3.6).
D RIVE INTERFAC E L INES A N D
Pin
2
4
6 8
10
Two Sided (Strappable) (TM848-2E only)
12
14
16
18
20
22
24
Motor On Control 4
26
28
30
32
34
Direction Select (Side Select Option, TM848-2E only)
36
Step
38
Write Data
40
Write Gate
l A
Track v
'+8
44
Write Protect
46
Read Data
48
Alternate I/O
50
Alternate I/O
Dri v e
T ABLE 3 - 1
P I N A S S I G N M E N T S
Signal
Write Current Switch
Motor On Control 1
Motor On Control 2
True Ready, (Motor On Control 3, Optional)
Disk Change (Strappable)
Side Select (TM848-2E only)
In Use Indicator (Strappable)
Head Load Line/Motor Control
Index
Ready
Drive Select 1 (Side Select Option, TM848-2E only)
Drive Select 2 (Side Select Option, TM848-2E only)
Drive Select 3 (Side Select Option, TM848-2E only)
Drive Select 4 (Side Select Option, TM848-2E only)
DIRECTION SELECT AND STEP LINES
(TWO LINES)
When the drive is selected, a true (low) pulse
on the Step line, with a t im e dur at ion greater
than on e
motion. The direction of motion is determined
b y the logic state of th e D i r ection Select li n e
w hen a s t e p p u l se i s i s sued. The m o t io n i s
toward the center of the disk if the Direction
Select line is in the true (low) state. The direc-
t ion of motion is away f rom th e center of t h e
disk if th e D i r ection Select line is in the false
(high) state.
To ensure p r oper p ositioning, t h e
S elect line should be stable at l east 1 m i c r o-
second. prior to the corresponding rising edge
of the step pulse, and remain stable 100 nano-
seconds after it.
3-3
m i c r osecond, i n i t i a te s t h e a c c ess
D i r e c t i on
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