Installation guide

PCI-SB StarFabric PCI Interface Card Installation Guide 2-13
PCI-SB Card in Detail
Leaf Mode
Leaf means the PCI-SB card requires resetting and enumeration from a Root bridge
in order to join and operate in the StarFabric network. All downstream nodes are set
to Leaf. A PCI-SB card acting as a Leaf bridge connects the remote or secondary
bus to a switch fabric or directly to a PCI-SB card configured as a Root bridge, as
shown in Figure 7.
FIGURE 7. Operating as a Leaf Mode Bridge in Path Routing Application
All Leaf nodes in an address-routed legacy PCI application are configured as
bridges and may require clocking and bus arbitration from an external source. The
Leaf expansion bridges are fully transparent and all PCI components on the second-
ary buses are fully visible to the primary bus.
PCI-SB card
configured as
Root bridge
Primary PCI Bus
From the StarFabric
expansion device
To the primary
PCI bus
Remote StarFabric
Other Leaf Bridge
Interface
PCI-SB card
configured as Leaf
bridge
Single board com-
puter for clock and bus
arbitration