Seagate ST373454FC Cheetah 15K.4 FC Product Manual - Page 80

The - Enable Bypass Port A - EN BYP Port A and - Enable Bypass Port B - EN BYP Port B signals

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Table 23: Active LED Out conditions Normal command activity Spun up and activity (command executing) Spinning up or down Format in progress, each cylinder change LED status Off Blinks steadily (50% on and 50% off) Toggles on/off The Active LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the proper +5 volt supply through an appropriate current limiting resistor. The LED and the current limiting resistor are external to the drive. 9.5.9 Enable port bypass signals The - Enable Bypass Port A (- EN BYP Port A) and - Enable Bypass Port B (- EN BYP Port B) signals control the port bypass circuits (PBC) located external to the disc drive. The PBC allows a loop to remain functional in the event of a drive failure or removal. When these signals are active, low, the PBC bypasses the drive on the associated port. When an Enable Bypass signal is active, the corresponding Port Bypass LED signal in connector J1 is driven low by the disc drive. A pull down resistor, 1K, located with the PBC should be used to insure the bypass is enabled if the disc drive is not installed. The Enable Bypass signal is active under failing conditions within the drive, on detection of the Loop Port Bypass primitive sequence, or on removal of the drive. In the bypass state the drive continues to receive on the inbound fibre. Enable Bypass may be deactivated by detection of a Loop Port Enable primitive sequence if the drive has completed self-test and a hardware failure is not present. Failure modes detected by the disc drive that will enable bypass include: • Transmitter/receiver wrap test failure • Loss of receive clock • Loss of transmission clock • Drive interface hardware error 9.5.10 Motor start controls The drive's motor is started according to the Start_1 and Start_2 signals described in Table 24. The state of these signals can be wired into the backplane socket or driven by logic on the backplane. Table 24: Motor start control signals Case 1 2 3 Start_2 Low High Low 4 High Start_1 Low Low High High Motor spin function Motor spins up at DC power on. Motor spins up only when SCSI Start command is received. Motor spins up after a delay of 12 seconds times the modulo 8 value of the numeric SEL ID of the drive from DC power on. The drive will not spin up. 9.5.11 SEL_6 through SEL_0 ID lines The SEL_6 through SEL_0 ID lines determine drive address, and, optionally, for an Enclosure Services Interface. When the Parallel ESI line is high, the enclosure backpanel must provide address information on the SEL line. Refer to table 25 for a mapping of SEL to FC-AL physical addresses (AL_PA). You can think of the SEL 68 Cheetah 15K.4 FC Product Manual, Rev. C

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68
Cheetah 15K.4 FC Product Manual, Rev. C
The Active LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the
proper +5 volt supply through an appropriate current limiting resistor. The LED and the current limiting resistor
are external to the drive.
9.5.9
Enable port bypass signals
The – Enable Bypass Port A (– EN BYP Port A) and – Enable Bypass Port B (– EN BYP Port B) signals control
the port bypass circuits (PBC) located external to the disc drive. The PBC allows a loop to remain functional in
the event of a drive failure or removal. When these signals are active, low, the PBC bypasses the drive on the
associated port. When an Enable Bypass signal is active, the corresponding Port Bypass LED signal in con-
nector J1 is driven low by the disc drive. A pull down resistor, 1K, located with the PBC should be used to
insure the bypass is enabled if the disc drive is not installed.
The Enable Bypass signal is active under failing conditions within the drive, on detection of the Loop Port
Bypass primitive sequence, or on removal of the drive. In the bypass state the drive continues to receive on the
inbound fibre. Enable Bypass may be deactivated by detection of a Loop Port Enable primitive sequence if the
drive has completed self-test and a hardware failure is not present.
Failure modes detected by the disc drive that will enable bypass include:
•
Transmitter/receiver wrap test failure
•
Loss of receive clock
•
Loss of transmission clock
•
Drive interface hardware error
9.5.10
Motor start controls
The drive’s motor is started according to the Start_1 and Start_2 signals described in Table 24. The state of
these signals can be wired into the backplane socket or driven by logic on the backplane.
9.5.11
SEL_6 through SEL_0 ID lines
The SEL_6 through SEL_0 ID lines determine drive address, and, optionally, for an Enclosure Services Inter-
face. When the Parallel ESI line is high, the enclosure backpanel must provide address information on the SEL
line. Refer to table 25 for a mapping of SEL to FC-AL physical addresses (AL_PA). You can think of the SEL
Spun up and activity (command executing)
Off
Spinning up or down
Blinks steadily (50% on and 50% off)
Format in progress, each cylinder change
Toggles on/off
Table 24:
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 times the modulo 8 value of
the numeric SEL ID of the drive from DC power on.
4
High
High
The drive will not spin up.
Table 23:
Active LED Out conditions
Normal command activity
LED status