Intel 31154 manual Introduction2, Product Overview, PCI-to-PCI Bridge Configurations, Pci-X

Introduction

Introduction2

2.1Product Overview

The Intel® 31154 133 MHz PCI Bridge (called hereafter the “31154”) is a PCI component that functions as a highly concurrent, low-latency transparent bridge between two PCI buses. The 31154 can operate as a PCI-to-PCI bridge in the configurations shown in Table 2.

Table 2.	PCI-to-PCI Bridge Configurations
	Primary Bus Interface	Secondary Bus Interface
	PCI 2.3	PCI 2.3
	PCI 2.3	PCI-X
	PCI-X	PCI 2.3
	PCI-X	PCI-X
	The 31154 is used on motherboards to provide additional I/O expansion slots. It is also used on PCI
	add-in cards to mitigate the restrictive electrical loading constraints imposed on an expansion slot,
	enabling multiple conventional PCI or multiple PCI-X devices to reside on a single PCI I/O
	adapter. The 31154 block diagram in Figure 1 indicates potential 31154 applications for a range of
	PCI bus speeds.
Figure 1.	Intel® 31154 133 MHz PCI Bridge Applications

Legacy￿￿￿￿￿￿

33 MHz

Bus	￿￿￿￿￿
PCI-X

LegacyMulti￿￿￿￿￿￿PCI-X

66￿￿￿￿￿￿MHzDevices

SlotsMHz66BusX-PCI	￿￿￿￿￿	SlotsMHz100BusX-PCI	￿￿￿￿￿
	￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

High￿￿￿￿￿￿-End

Application

Slot	￿￿￿￿￿
PCI-X Bus 133 MHz

CPU Host

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿

￿￿￿￿￿￿￿￿

Intel® 31154 133 MHz PCI Bridge Design Guide Design Guide 9