Installation Guide, Third Edition - Server Expansion Unit

Chapter 1
Introduction
Detailed Server Expansion Unit Description
11
Figure 1-6 PCI-X Board to Cell Board Block Diagram
The Server Expansion Unit supports two internal SBAs. The SBAs generate 32 rope buses (16 per SBA). The
32 available internal rope buses are divided in the following manner:
• Two ropes are routed as single rope bundles to support the core I/O boards through LBAs located on the
core I/O backplane.
• Two ropes are routed as single rope bundles to two LBAs to support two slots for PCI and PCI-X cards.
• Twenty-eight ropes are bundled in two rope pairs to 14 LBAs to support 14 slots for PCI and PCI-X cards.
The PCI-X backplane is the primary I/O interface for Server Expansion Unit systems. It provides 16 64-bit,
hot-plug PCI/PCI-X slots. Fourteen of the slots have dual ropes connected to the LBA chips. The remaining
two slots have a single rope connected to each LBA chip. Each of the 16 slots is capable of 66MHz/33MHz PCI
or 133MHz/66MHz PCI-X. All 16 PCI slots are keyed for 3.3V connectors (accepting both Universal and 3.3V
cards). The PCI-X backplane does not provide any 5V slots for the I/O cards.
The external link for the Server Expansion Unit attaches the cell controller on cell board 2 to SBA 0 and
attaches the cell controller on cell board 3 to SBA 1 of the PCI-X board in the Server Expansion Unit cabinet.
The PCI-X backplane is physically one board but behaves like two independent partitions. SBA 0 and its
associated LBAs and eight PCI-X slots form one I/O partition. SBA 1 and its associated LBAs and eight PCI-X
slots form the other I/O partition. One I/O partition can be powered down separate from the other I/O
partition.
PCI Slot 8LBA 1
Cell
Controller
(CC)
Cell Board
PCI Slot 7LBA 2
PCI Slot 6LBA 4
PCI Slot 5LBA 6
PCI Slot 4LBA 14
PCI Slot 3LBA 12
PCI Slot 2LBA 10
PCI Slot 1LBA 8
System Bus
Adapter (SBA)
System
LBA
Backplane
Adapter (SBA)
System Bus
PCI Slot 8LBA 1
PCI Slot 2
PCI Slot 1
PCI Slot 3
LBA 8
LBA 10
LBA 12
PCI Slot 4
PCI Slot 5
PCI Slot 6
PCI Slot 7
LBA 4
LBA 6
LBA 14
LBA 2
LBA
Controller
Cell Board
Cell
(CC)