82X38 datasheet(21/342 Pages) INTEL

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Datasheet

Introduction

1.2.4

PCI Express* Interface

The MCH supports two 16-lane (x16) PCI Express ports. The PCI Express ports are

compliant to the PCI Express* Base Specification revision 2.0. The x16 ports operate at

a frequency of 5 Gb/s on each lane while employing 8b/10b encoding, and support a

maximum theoretical bandwidth of 8.0 GB/s in each direction.

The PCI Express interface includes:

• Two, 16-lane PCI Express ports intended for external device attach, compatible to

the PCI Express* Base Specification, Revision 2.0.

• PCI Express frequency of 2.5 GHz resulting in 5.0 Gb/s each direction per lane.

• Raw bit-rate on the data pins of 5.0 Gb/s, resulting in a real bandwidth per pair of

500 MB/s given the 8b/10b encoding used to transmit data across this interface

• Maximum theoretical realized bandwidth on the interface of 8 GB/s in each

direction simultaneously, for an aggregate of 16 GB/s when x16.

• PCI Express Enhanced Addressing Mechanism allows for accessing the device

configuration space in a flat memory mapped fashion.

• Automatic discovery, negotiation, and training of link out of reset.

• Supports traditional PCI style traffic (asynchronous snooped, PCI ordering)

• Supports traditional AGP style traffic (asynchronous non-snooped, PCI Express-

relaxed ordering)

• Hierarchical PCI-compliant configuration mechanism for downstream devices

(i.e., normal PCI 2.3 Configuration space as a PCI-to-PCI bridge).

• Supports “static” lane numbering reversal. This method of lane reversal is

controlled by a Hardware Reset strap, and reverses both the receivers and

transmitters for all lanes (e.g., TX[15]->TX[0], RX[15]->RX[0]). This method is

transparent to all external devices and is different than lane reversal as defined in

the PCI Express Specification. In particular, link initialization is not affected by

static lane reversal.

• When two, 16-lane PCI Express ports are used, the second port supports either PCI

Express Gen1.1 I/O cards with x8, x4 or x1 lanes or PCI Express Gen1/Gen2

Graphics cards with x16 or x1 lanes.

82X38 Datasheet(PDF) 21 Page - Intel Corporation