Intel CONTROLLERS 413808 - Manual (Page 132)

Intel
®
413808 and 413812—Address Translation Unit (PCI-X)
Intel ® 413808 and 413812 I/O Controllers in TPER Mode
Developer’s Manual October 2007
132 Order Number: 317805-001US
2.12 Central Resource Functionality
Central Resource is not supported on 4138xx.
2.12.1 Multi-Function Support
When operating as a central resource, the ATU behaves as a single function device and
claims memory transactions only for the ATU function. This means that the BARs and
control signals from other internal functions are ignored, and any PCI status updates
are limited to the ATU.
2.12.2 Outbound Transactions
ATU outbound transaction support is detailed in Section 2.2.2, “Outbound Transactions-
Single Address Cycle (SAC) Internal Bus Transactions” . The behavior is the same in
both end point and central resource modes of operation.
2.12.3 PCI Reset (P_RSTOUT#)
When the Central Resource is enabled ( PCIX_EP# = 1), the ATU controls generation of
P_RSTOUT# for the PCI Bus segment attached to the ATU.
The ATU controls the PCI Reset signal ( P_RSTOUT# ) for the external agents supported
by the 4138xx Central Resource. When the Central Resource is enabled, P_RSTOUT#
remains asserted following the deassertion of the fundamental reset. P_RSTOUT# can
be deasserted in the “PCI Configuration and Status Register - PCSR” on page 178 .
2.12.4 PCI Clock Outputs (P_CLKOUT, P_CLKO[3:0])
The P_CLKOUT / P_CLKO[3:0] PCI clock outputs are available when operating in
central resource mode and the primary clock source is the PCI Express* reference clock
( CLK_SRC_PCIE# = 0). In this operating mode, the P_CLKOUT signal is connected
to the P_CLKIN pin and trace match to the P_CLKO[3:0] signals.
Warning:
When the P_CLKIN is the primary clock source ( CLK_SRC_PCIE# = 1), the PCI Clock
outputs are disabled and cannot be used as a clock source for any device.