Seagate ST3400071FC ユーザーズマニュアル

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NL35 Series FC Product Manual, Rev. D

The Active LED Out signal is driven by the drive as indicated in Table 30.

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.

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

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, each cylinder change

Toggles on/off