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4.2.4
4.2.5
There are three conditions detected:
a)
Write current in a head without WRITE GATE
active or no write current in the head with
WRITE GATE active and DRIVE SELECTED.
b)
Multiple heads selected, no head selected,
or improperly selected.
c)
DC voltages are grossly out of tolerance.
INDEX
This interface signal is provided by the drive once
each revolution (16.67mS nom.) to indicate the
beginning of the track.
Normally, this signal is a
logical one level and makes the transition to the
logical zero level to indicate INDEX.
Only the
transition from one to zero is valid.
See Figure 9.
FIGURE 9
INDEX TIMING
I~
l6.67mS nom.
--...t
u
U
----I 1"-
200}l sec typ.
READY
This interface signal when true together with
SEEK COMPLETE, indicates that the drive is ready
to read, write or seek, and that the I/O signals
are valid.
When this line is false, all writing
and seeking are inhibited.
The typical time after power on for READY to
be
true is 15 seconds.
4.3
DATA TRANSFER LINES
All lines associated with the transfer of data between the
drive and the host system are differential in nature and
may not be multiplexed.
These lines are provided at the
J2/P2 connectors on all drives •.
20
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