Seagate ST11200N Product Manual page 25

Product Manual - Hawk 1 Family SCSI-2 (Volume 1), Rev. D
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The servo/read-write LSI on the master drive provides the reference signal (REFIND+). It is a 90.18 Hz
crystal generated signal. The signal is normally false/negated (nominal 0 V) and makes a transition to the
true/asserted (nominal +5 V) level to indicate the reference position during the revolution period. The trailing
(falling) edge of the reference signal is used by the master and the slave drives to phase lock their spindles.
A maximum of 10 seconds is allowed for a slave to synchronize with the reference signal. Figure 5.7-2
shows the characteristics of the reference signal.
1
REFIND +
0
T = 0.0111 second (+/- 1.0% max); +/- 10 usec cycle to cycle variance;
+/- 50 usec phase error while synchronized.
Figure 5.7-2. Synchronized reference signal characteristics
SCSI Interface Factors
The Rotational Position Locking (RPL) field in byte 17 (bits 0 and 1) of the Rigid Disc Drive Geometry mode
parameters page (page 04h) is used for enabling/disabling spindle synchronization mode*. If the target fails
to achieve synchronization, it shall create a unit attention to all initiators. The sense key shall be set to UNIT
ATTENTION and the additional sense code set to RPL STATUS CHANGE. However, in automatic arbitra-
tion mode, UNIT ATTENTION and the RPL STATUS CHANGE is not set.
If subsequent to achieving synchronization the target detects a change of synchronization:
1) and, if the logical unit is not presently executing an I/O process for the initiator, the target shall create a
unit attention condition. The sense key shall be set to UNIT ATTENTION and the additional sense code
set to RPL STATUS CHANGE.
2) and, if the logical unit is presently executing an I/O process and no other error occurs, the target shall
return CHECK CONDITION status. The sense key shall be set to RECOVERED ERROR if the target is
able to complete the I/O process or HARDWARE ERROR if the target is unable to complete the I/O
process. The additional sense code is set to RPL STATUS CHANGE.
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*SCSI Interface Product Manual P/N 77738479.
T
0.5 usec min.
500 usec max.
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