3.3.2
Head Load
When the disk drive is in the ready state, a Low on this
line initiates loading of the read/write heads.
3.3.3
Step (STP)
This pulse directs the stepping motor to move the read/write
heads from track to track.
determined
by
3.3.4).
Figure 3-3 shows the repetition rate and width of
the Step pulse.
(positive-going)
heads 1/2 track.
3.3.4
Direction Select (DIR)
If
the Direction
toward the external tracks.
toward the internal tracks.
nal occurs 1 | i s before the leading edge of the STP signal.
3.3.5
Side Select (SSL)
This signal selects the side of the disk that is used for
the
read/write operation.
High, side 0 (upper side) is selected.
1 (lower side)
disk is used, side 0 is selected.
at least 100 ys before the read/write operation begins.
(HDL)
the
Direction
The heads start to move at the leading
edge of each pulse.
Figure 3-3
Step Signal Timing
Select
signal
If
is selected.
3-4
The direction of movement
Select
signal
One pulse moves the
is High,
If DIR is Low, the head moves
The trailing edge of this sig
the
Side
Select
If SSL is Low, side
When a single-sided flexible
The SSL signal must occur
is
(see
Section
the head moves
signal
is