Version 1.6 2007
Features
PEX 8518
PEX 8518 General Features
o 16-lane PCI Express switch
- Integrated SerDes
o Up to five configurable ports
o 23mm x 23mm, 376-ball PBGA
package
Flexible & Versatile PCI Express® Switch
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.
o Typical Power: 2.6 Watts
PEX 8518 Key Features
o Standards Compliant
- PCI Express Base Specification, r1.1
- Standard SHPC Specification, r1.1
(hot-plug)
o High Performance
Highly Flexible Port Configurations
- Non-blocking internal architecture
- Full line rate on all ports
- Cut-Thru latency: 150ns
o Non-Transparent Bridging
- Configurable Non-Transparent port
for Multi-Host or Intelligent I/O
Support
o Flexible Configuration
- Five highly flexible & configurable
ports (x1, x2, x4, or x8)
- Configurable with strapping pins,
EEPROM, I2C, or Host software
- Lane and polarity reversal
o PCI Express Power Management
- Link power management states: L0,
L0s, L1, L2/L3 Ready, L2 and L3
- Device states: D0 and D3hot
- Vaux, WAKE#, Beacon support
o Spread Spectrum Clock
- Dual clock domain
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.
o Quality of Service (QoS)
- Two Virtual Channels per port
- Eight Traffic Classes per port
- Fixed and Round-Robin Virtual
Channel Port Arbitration
o Reliability, Availability, Serviceability
- 5 Standard Hot-Plug Controllers
- Upstream port as hot-plug client
- Transaction Layer end-to-end CRC
- Poison bit
- Advanced Error Reporting
- Lane Status bits and GPO available
- Per port error diagnostics
• Bad DLLPs
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.
• Bad TLPs
• CRC errors
- JTAG boundary scan
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.
- Fatal Error out-of-band signal option