Version 0.8 2007
Features
PEX 8648 General Features
o
48-lane, 12-port PCIe Gen2 switch
-
Integrated 5.0 GT/s SerDes
o
27 x 27mm
2
, 676-pin FCBGA package
o
Typical Power: < 7.0 Watts
PEX 8648
PCIe Gen2, 5.0GT/s 48-lane, 12-port PCIe Switch
The
ExpressLane
TM
PEX 8648 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, and communications platforms.
The PEX 8648 is well suited for
fan-out, aggregation, and peer-to-peer
applications.
High Performance & Low Packet Latency
The PEX 8648 architecture supports packet
cut-thru with a maximum
latency of 140ns (x16 to x16).
This, combined with large packet memory
and non-blocking internal switch architecture, provides full line rate on all
ports for performance-hungry applications such as
servers
and
switch
fabrics.
The low latency enables applications to achieve high throughput and
performance. In addition to low latency, the device supports a packet payload
size of up to 2048 bytes, enabling the user to achieve even higher throughput.
Data Integrity
The PEX 8648 provides
end-to-end CRC
(ECRC) protection and
Poison bit
support to enable designs that require
end-to-end data integrity.
PLX also
supports data path parity and memory (RAM) error correction as packets
pass through the switch.
Flexible Register & Port Configuration
The PEX 8648’s 12 ports can be configured to lane widths of x1, x2, x4, x8,
or x16. Flexible buffer allocation, along with the device's
flexible packet
flow control,
maximizes throughput for applications where more traffic
flows in the downstream, rather than upstream, direction. Any port can be
designated as the upstream port, which can be changed dynamically. The
PEX 8648 also
x4
x8
provides several ways
to configure its
registers. The device
can be configured
PEX 8648
PEX 8648
through strapping pins,
I
2
C interface,
host
software, or an optional
3 x8 4 x4
11 x4
serial EEPROM. This
allows for easy debug
x8
x8
during the development
phase, performance
monitoring during the
operation phase, and
PEX 8648
PEX 8648
driver or software
upgrade. Figure 1
shows some of the PEX
2 x8 4 x4
8648’s common port
10 x4
configurations.
Figure 1. Common Port Configurations
PEX 8648 Key Features
o
Standards Compliant
-
PCI Express Base Specification, r2.0
(backwards compatible w/ PCIe r1.0a/1.1)
-
PCI Power Management Spec, r1.2
-
Microsoft Vista Compliant
-
Supports Access Control Services
-
Dynamic link-width control
-
Dynamic SerDes speed control
o
High Performance
-
Non-blocking switch fabric
-
Full line rate on all ports
-
Packet Cut-Thru with 140ns max packet
latency (x16 to x16)
-
2KB Max Payload Size
-
Read Pacing (bandwidth throttling)
-
Dual-Cast
o
Flexible Configuration
-
Ports configurable as x1, x2, x4, x8, x16
-
Registers configurable with strapping
pins, EEPROM, I
2
C, or host software
-
Lane and polarity reversal
-
Compatible with PCIe 1.0a PM
o
Dual-Host & Fail-Over Support
-
Configurable Non-Transparent port
-
Moveable upstream port
-
Crosslink port capability
o
Quality of Service (QoS)
-
Eight traffic classes per port
-
Weighted round-robin source
port arbitration
o
Reliability, Availability, Serviceability
-
3 Hot Plug Ports with native HP Signals
-
All ports hot plug capable thru I
2
C
(Hot Plug Controller on every port)
-
ECRC and Poison bit support
-
Data Path parity
-
Memory (RAM) Error Correction
-
INTA# and FATAL_ERR# signals
-
Advanced Error Reporting
-
Port Status bits and GPIO available
-
Per port error diagnostics
-
Performance Monitoring
•
Per port payload & header counters
-
JTAG AC/DC boundary scan
Preliminary - PLX Confidential
PLX [ PLX TECHNOLOGY ]
