Step Signal Timing - NEC FD1165 Maintenance Manual

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