Seagate ST9900805SS Savvio 10K.4 FC Product Manual - Page 68

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

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9.5.8 Active LED Out The Active LED Out signal is driven by the drive as indicated in Table 22. Table 22: Active LED Out conditions Normal command activity Spun down and no activity Spun down and activity (command executing) Spun up and no activity Spun up and activity (command executing) Spinning up or down Format in progress Write Same command in progress LED status Slow blink (20% on and 80% off a 2 sec cycle) On On Off Blinks steadily (50% on and 50% off) Toggles on/off Togles 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 disk 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 disk drive. A pull down resistor, 1K, located with the PBC should be used to insure the bypass is enabled if the disk drive is not installed. Failure modes detected by the disk 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 23. The state of these signals can be wired into the backplane socket or driven by logic on the backplane. Table 23: Motor start control signals Case 1 2 3 4 Start_2 Low High Low 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. 62 Savvio 10K.4 FC Product Manual, Rev. A

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62
Savvio 10K.4 FC Product Manual, Rev. A
9.5.8
Active LED Out
The Active LED Out signal is driven by the drive as indicated in Table 22.
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 disk 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 disk drive. A pull down resistor, 1K, located with the PBC should be used to
insure the bypass is enabled if the disk drive is not installed.
Failure modes detected by the disk 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 23. The state of
these signals can be wired into the backplane socket or driven by logic on the backplane.
Table 22:
Active LED Out conditions
Normal command activity
LED status
Spun down and no activity
Slow blink (20% on and 80% off a 2 sec cycle)
Spun down and activity (command executing)
On
Spun up and no activity
On
Spun up and activity (command executing)
Off
Spinning up or down
Blinks steadily (50% on and 50% off)
Format in progress
Toggles on/off
Write Same command in progress
Togles on/off
Table 23:
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.