Control Signals - HP Vectra Reference Manual

Control Signals
Signal I/O
Description
-DIRECTION 0
Active level indicates the read/write head
to move toward the spindle. Inactive
level instructs the heads to move away
from the spindle.
- DS1 or - DS2
0
Drive select lines 1 or 2 are used by
drives 1 and 2 to degate all adapter and
receiver drivers from the attachment,
except - MOTEN, when the line
associated with a drive is inactive.
-- HEAD SELECT
0
Head 1 will be selected when this line is
active. An inactive level will select the
head on side
O.
- MOTEN1 or
0
- MOTEN controls the spindle motor of
~.
-MOTEN2 the drive (1 or 2) associated with each
line. The line controls the spindle motor
such that it starts when the line becomes
active and stops when the line becomes
inactive.
-REDWRCUR
0
Selects read channel filters and write
current on the 1.2 MB drive. It is active
only when the PLL is in 300kHz mode
and inactive for the 500kHz and 250kHz
modes.
-STEP
0
The selected drive moves the read/write
head one cylinder in or out per the
direction line for each pulse present on
this line. Motion is started each time the
signal changes from an active to inactive
,..
level.
- WRITE ENABLE
0
Disables write current in the drive head
unless this line is active.
Processor Board 51