Flexible & Versatile PCI Express

Features

PEX 8518 General Features

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16-lane PCI Express switch

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Integrated SerDes

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Up to five configurable ports

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23mm x 23mm, 376-ball PBGA

package

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Typical Power: 2.6 Watts

PEX 8518 Key Features

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Standards Compliant

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PCI Express Base Specification, r1.1

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Standard SHPC Specification, r1.1

(hot-plug)

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High Performance

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Non-blocking internal architecture

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Full line rate on all ports

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Cut-Thru latency: 150ns

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Non-Transparent Bridging

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Configurable Non-Transparent port

for Multi-Host or Intelligent I/O

Support

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Flexible Configuration

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Five highly flexible & configurable

ports (x1, x2, x4, or x8)

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Configurable with strapping pins,

EEPROM, I

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Lane and polarity reversal

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PCI Express Power Management

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Link power management states: L0,

L0s, L1, L2/L3 Ready, L2 and L3

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Device states: D0 and D3hot

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Vaux, WAKE#, Beacon support

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Spread Spectrum Clock

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Dual clock domain

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Quality of Service (QoS)

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Two Virtual Channels per port

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Eight Traffic Classes per port

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Fixed and Round-Robin Virtual

Channel Port Arbitration

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Reliability, Availability, Serviceability

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5 Standard Hot-Plug Controllers

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Upstream port as hot-plug client

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Transaction Layer end-to-end CRC

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Poison bit

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Advanced Error Reporting

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Lane Status bits and GPO available

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Per port error diagnostics

• Bad DLLPs

• Bad TLPs

• CRC errors

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JTAG boundary scan

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Fatal Error out-of-band signal option

Multi-purpose, Feature Rich ExpressLane™ PCI Express Switch

The ExpressLane PEX 8518 device offers PCI Express switching capability

enabling users to add scalable high bandwidth, non-blocking interconnection

to a wide variety of applications including servers, storage systems,

communications platforms, blade servers, and embedded-control

products. The PEX 8518 is well suited for fan-out, aggregation, peer-to-

peer, and intelligent I/O module applications.

Highly Flexible Port Configurations

The PEX 8518 offers highly configurable ports. There are a maximum of five

ports that can be configured to any legal width from x1 to x8, in any

combination to support your specific bandwidth needs. The ports can be

configured for symmetric (each port having the same lane width and traffic

load) or asymmetric (ports having different lane widths) traffic. In the event

of asymmetric traffic, the PEX 8518 features a flexible central packet

memory that allocates a memory buffer for each port as required by the

application or endpoint. This buffer allocation along with the device's

flexible packet flow control minimizes bottlenecks when the upstream and

aggregated downstream bandwidths do not match (are asymmetric). Any of

the ports can be designated as the upstream port, which can be changed

dynamically.

End-to-end Packet Integrity

The PEX 8518 provides end-to-end CRC protection (ECRC) and Poison bit

support to enable designs that require guaranteed error-free packets. These

features are optional in the PCI Express specification, but PLX provides

them across its entire ExpressLane switch product line.

Non-Transparent “Bridging” in a PCI Express Switch

The PEX 8518 supports full non-transparent bridging (NTB) functionality to

allow implementation of multi-host systems and intelligent I/O modules in

applications such as communications, storage, and blade servers. To

ensure quick product migration, the non-transparency features are

implemented in the same fashion as in standard PCI applications.

Non-transparent bridges allow systems to isolate memory domains by

presenting the processor subsystem as an endpoint, rather than another

memory system. Base address registers are used to translate addresses;

doorbell registers are used to send interrupts between the address domains;

and scratchpad registers are accessible from both address domains to allow

inter-processor communication.

Two Virtual Channels

The ExpressLane PEX 8518 switch supports two full-featured Virtual

Channels (VCs) and eight Traffic Classes (TCs). The mapping of Traffic

Classes to port-specific Virtual Channels allows for different mappings for

different ports. In addition, the devices offer user-selectable Virtual Channel

arbitration algorithms to enable users to fine tune the Quality of Service

(QoS) required for a specific application.

PEX 8518

Version 1.6 2007