Product manual

16 Product Manual - Hawk 2 Family (Wide bus) SCSI-2 (Volume 1), Rev. A
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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. The DLYIND+
signal (available on J7-6 See Figure 5.7-1) of each synchronized drive shall occur 85.2 µsec ±20 µsec after
the REFIND+ signal. Figure 5.7-2 shows the characteristics of the reference signal.
T = 0.0111 second (+/- 1.0% max); +/- 10 µsec cycle to cycle variance;
Figure 5.7-2. Synchronized reference signal characteristics
The physical characteristics of the synchronized spindle interface are described in Section 10.2.
T
0.5 usec min.
500 usec max.
0
1
REFIND +