~
r-f
"'f
- ....1 f
~ON
1
1----
·1
24
sec.
---I
18sec
typo
1--
ROTAnONAL f f
SPEED REGULATED
f
- SEEK COMPLETE
-READY
(660
revs
counted)
--t
=.
1-
-TRACK
G 1 J f
110.0.
_
--t
~
16.67nsec max.
J 1...
--41
1
11-
_
1
21__J
r--
max.
-r
FIGURE
16:
Typical
Power-up
Sequence
SEEK COMPLETE
5.5
This signal goes low
on
the
interface when the Read/Write heads have settled
on
track
upon
completion
of
a seek. Seeking, reading
or
writing should
not
be
attempted when SEEK
COMPLETE
is false. SEEK
COMPLETE
goes false in
the following four cases:
1.
When
a recalibration sequence is initiated (by drive logic)
at
power-on.
2.
100 nsec. max. after the leading edge
of
a Step pulse.
3.
If
either +5 Volts
or
+
12
Volts are detected as unsafe.
WRITE
FAULT
5.6
This signal indicates
that
a condition exits
at
the drive which,
if
not
corrected,
may cause
an
incorrect write operation. WRITE FAULT will remain
true
until
the condition causing the fault is corrected. The controller should edge detect
this signal.
WRITE FAULT SIGNAL GENERATION
5.6.1
With DRIVE SELECT active,
and
one
of
the following conditions true,
the
WRITE
FAULT signal will be issued
to
the interface
and
Write Current will be
inhibited.
1.
Write Gate
true
with
no
Write Current flowing
to
the head
2. Write Current
to
the
heads with
no
Write Gate
ST212 PRODUCT MANUAL/Rev. B
19
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