Flexible Port Width Configuration

The lane width for each port can be individually configured

through auto-negotiation, hardware strapping, upstream

software configuration, or through an optional EEPROM.

The PEX 8532 supports a large number of port configurations.

For example, if you are using the PEX 8532 in a fan-out

application (such as in Figure 1), you may configure the

upstream port as x8 and the downstream ports as six x4 ports;

two x8 & two x4 ports; three x8 ports; or any other

combination as long as you don’t run out of lanes (32) or ports

(8). For a peer-to-peer application, you can configure all eight

ports as x4 or x2, or a combination of the two. In a port

aggregation application, you can configure four x2 or x4 ports

for aggregation into one x8 or x16 port.

Hot Plug for High Availability

Hot plug capability allows users to replace hardware modules

and perform maintenance without powering down the system.

The ExpressLane PEX 8532 hot plug capabilities and

advanced error reporting features make them suitable for

High Availability (HA) applications. Each downstream port

includes a Standard Hot Plug Controller. If the PEX 8532 is

used in an application where one or more of its downstream

ports connect to PCI Express slots, each port’s Hot Plug

Controller can be used to manage the hot-plug event of its

associated slot. Furthermore, its upstream port is a hot-plug

client, allowing it to be used on hot-pluggable adapter

cards, backplanes and fabric modules.

Fully Compliant Power Management

For applications that require power management, the

ExpressLane PEX 8532 device support both link (L0, L0s, L1,

L2/L3 Ready, and L3) and device (D0 and D3hot) power

management states, in compliance with the PCI Express power

management specification.

SerDes Power and Signal Management

The ExpressLane PEX 8532 supports software control of the

SerDes outputs to allow optimization of power and signal

strength in a system. The PLX SerDes implementation

supports four levels of power – off, low, typical and high. The

SerDes block also supports loop-back modes and advanced

reporting of error conditions, which enables efficient debug

and management of the entire system.

Flexible Virtual Channel Arbitration

The ExpressLane PEX 8532 switch supports hardware fixed

and Round Robin arbitration schemes for two virtual channels.

This allows fine tuning of Quality of Service, optimum use of

buffers and efficient use of the system bandwidth.

Applications

Suitable for host-centric as well as peer-to-peer traffic

patterns, the ExpressLane PEX 8532 can be configured for a

wide variety of form factors and applications.

Host Centric Fan-out

The ExpressLane PEX 8532 device, with its versatile

symmetric or asymmetric lane configuration capability, allows

user specific tuning to a variety of host-centric applications.

Figure 1. Fan-in/out Usage

Figure 1 shows a typical server-based design, where the root

complex provides a PCI Express link that needs to be

expanded into a larger number of smaller ports for a variety of

I/O functions each with different bandwidth requirements.

The ExpressLane PEX 8532 would typically have an 8-lane

upstream port, and as many as 7 downstream ports. The

downstream ports can be of differing widths if required. The

figure also shows how some of the ports can be bridged to

provide PCI or PCI-X through the use of the ExpressLane

PCIe bridges such as PEX 8114 and PEX 8111.

Peer-to-Peer & Backplane Usage

Figure 2 represents a backplane where the ExpressLane PEX

8532 provides peer-to-peer data exchange for a large number

of line cards where the CPU/Host plays the management role.

Figure 2. Peer-to-Peer/Backplane Usage