Chapter 1. Product Description
EK–SMCPP–UG. A01
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1.2.3.2 Controlling the Internal SCSI Bus
The I/O module controls the internal SCSI bus in the following manner:
•
Isolates the internal SCSI bus from the external SCSI bus.
•
Provides single-ended SCSI bus termination.
•
Disconnects the internal SCSI bus from the external SCSI bus when the
EMU so directs.
•
Distributes TERMPOWER (+5 V dc) to the internal SCSI bus.
•
Turns ON the green internal TERMPOWER LED (see Figure 1-8) when the
internal TERMPOWER is present.
•
Turns OFF the green internal TERMPOWER LED (see Figure 1-8) when
there is an internal TERMPOWER overcurrent condition.
1.2.3.3 Controlling the External SCSI Bus
The I/O module controls the external SCSI bus in the following manner:
•
Provides single-ended SCSI bus termination.
•
Distributes TERMPOWER (+5 V dc) to the external SCSI bus.
•
Turns ON the green external TERMPOWER LED (see Figure 1-8) when the
external TERMPOWER is present.
•
Turns OFF the green external TERMPOWER LED(see Figure 1-8) when
there is an external TERMPOWER overcurrent condition.
•
Automatically disables the external bus termination when a cable is
connected to the right hand VHDCI connector.
1.2.3.4 Controlling the Fault Bus
The I/O module controls the fault bus operation in the following manner:
•
Provides a fault bus driver for improved signal transmission.
•
Distributes the FAULT_CLK and FAULT_DATA signals from the master
enclosure to the expansion enclosures.
•
Distributes the SHELF_OK and SWAP_L signals from the expansion
enclosures to the master enclosure.
1.2.3.5 “Warm Swapping” I/O Modules and Cables
You can replace either the I/O module or a cable when the associated SCSI bus is
quiesced (no data transfers occurring) – a warm swap. This enables you to
correct problems affecting only one bus without disrupting data transfers on the
other five buses.
