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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Figure 2. Peer-to-Peer/Backplane Usage
PLX [ PLX TECHNOLOGY ]
