Seagate CHEETAH ST34501FC, Руководство по эксплуатации продукта

Страница: 55 / 68

Cheetah 4LP FC Product Manual, Rev. A 45
9.5.10 Motor start controls
The drive’s motor is started according to the Start_1 and Start_2 signals described in Table 17. The state of
these signals can be wired into the backplane socket or driven by logic on the backplane.
*This value may be reduced by drive suppliers to reflect the worst case time duration of peak current drains at
the 12 Volt of 5 Volt source (or both) during motor spin up. The delay should never exceed 12 seconds.
9.5.11 SEL ID lines
The SEL_6 through SEL_0 ID lines provide a binary decode associated with a physical unit for the full addres-
sable logic range and beyond of the FC-AL. Refer to Table 18 for the SEL to FC-AL physical addresses (AL-
PA). You can think of the SEL lines as the equivalent of a backpanel logic plug. The drive does not provide pull
up resistors on these lines. The backpanel is required to provide high and low inputs to the SEL-ID lines as
described in Section 9.6.1.
SEL setting 7F hex maps to a valid AL-PA. This value signals to the drive that physical addresses are not
being assigned through the SEL lines and that a “soft” address is being assigned using the FC-AL initialization
sequence.
Table 18 provides the AL-PA values for each SEL value. The first entry in the table is switch SEL_ID = 00. The
last entry is switch SEL_ID = 7D. Switch SEL_ID value 7E is AL-PA 00 which is not valid for a NL_Port and is
therefore not lincluded in the table.
Table 17: Motor start control signals
Case Start_2 Start_1 Motor spin function
1 Low Low Motor spins up at DC power on.
2 High Low Motor spins up only when SCSI Start command is received.
3 Low High Motor spins up after a delay of 12* seconds (max) times the module 8
value of the numeric SEL ID of the drive from DC power on.
4 High High The drive will not spin up.