Control And Data Line Functions - Control Data Corporation BR8 SERIES Hardware Maintenance Manual

4.4.4 CONTROL AND DATA LINE FUNCTIONS
The signals that are exchanged are described in Table 4-2 and are shown relative to
a point of origin in Figure 4-1.
SIGNAL
INPUT LINES
-STEP
}**
I
-DIRECTION)
"
"
-STEP IN
J
\ **
-STEP OUT
,)
-HEAD LOAD
Table 4-2. Input/Output Lines
FUNCTION
A
10
microsecond (minimum) logic
1
level pulse on this
line causes the head to move one track as determined by
the direction line.
A logic 1 level on this line and step pulse causes the head
to move one track inward toward the center of the diskette.
A logic
0
level on this line and step pulse causes the head
to move one track outward from the center of the diskette.
A
10
microsecond (minimum) logic
1
level pulse on this
line causes the head to move one track inward toward the
center of the diskette.
A
10
microsecond (minimum) logic
1
level pulse on this
line causes the head to move me track outward from the
center of the diskette.
A logic 1 level on this line loads the diskette against the
head through the use of a pressure pad on the opposing
side of the diskette. The logic 1 level must be initiated
60 milliseconds prior to initiating a read or write opera-
tion to allow for head load settling time.
For increased head and media life, this signal should be at
a logic 0 whenever a data transfer operation is not in process
or pending.
**Only one pair of signals per FDD.
4-8
77834769-A
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