9.5.8Active 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 | LED status |
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Spun down and no activity | Slow blink (20% on and 80% off a 2 sec cycle) |
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Spun down and activity (command executing) | On |
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Spun up and no activity | On |
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Spun up and activity (command executing) | Off |
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Spinning up or down | Blinks steadily (50% on and 50% off) |
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Format in progress | Toggles on/off |
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Write Same command in progress | Togles on/off |
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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.
9.5.9Enable 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
9.5.10Motor 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 |
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Case | Start_2 | Start_1 | Motor spin function |
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1 | Low | Low | Motor spins up at DC power on. |
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2 | High | Low | Motor spins up only when SCSI Start command is received. |
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3 | Low | High | Motor spins up after a delay of 12 seconds times the modulo 8 value |
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| of the numeric SEL ID of the drive from DC power on. |
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4 | High | High | The drive will not spin up. |
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62 | Savvio 10K.4 FC Product Manual, Rev. A |
