Port Configurations
SerDes Power and Signal Management
The ExpressLane PEX 8509 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.
The lane width of each port can be individually configured
through auto-negotiation, hardware strapping, host software
configuration, I2C interface, or through an optional EEPROM.
The PEX 8509 supports 4 port configurations:
1) One x1 upstream port and seven x1 downstream ports
2) One x2 upstream port and six x1 downstream ports
3) One x2 upstream port and the downstream ports as one x2
and four x1
Port Arbitration
4) One x4 upstream port and four x1 downstream ports
The PEX 8509 switch supports hardware fixed and Weighted
Round-Robin Ingress Port Arbitration. This allows fine
tuning of Quality of Service and efficient use of packet buffers
and the system bandwidth.
x1
x2
Applications
PEX 8509
PEX 8509
Suitable for docking stations, control plane applications,
multi-function printers, DVRs, industrial control systems,
medical imaging systems, embedded systems & AMC
modules, the PEX 8509 can be configured for a wide variety
of form factors and applications.
all x1
x4
all x1
x2
Docking Station
The PEX 8509 is the most cost-effective PCI Express switch
that can be used in a docking station application. Figure 2
shows four x1 downstream ports connecting two PCIe end-
points, a Network Card and an ExpressCard to a single x4
upstream port. The PEX 8509’s Hot-Plug feature is extremely
useful for the plugging/un-plugging of ExpressCards.
PEX 8509
PEX 8509
x1
x1x1 x2
x1
x1 x1 x1 x1
Mother Board
Graphics
CPU
Figure 1. Port Configurations
For eight-lane configurations not shown in Figure 1, please
use the PEX 8508 device which offers more configuration
options in an 8-lane switch.
Memory
North
Bridge
Hot Plug for High Availability
South
Hot Plug capability allows users to replace hardware modules
and perform maintenance without powering down the system.
The PEX 8509 Hot Plug capability and Advanced Error
Reporting features make it suitable for High Availability
(HA) applications. Ports 1, 2 & 3 include a Standard Hot
Plug Controller. If the PEX 8509 is used in an application
where one or more of its downstream ports connect to PCI
Express slots, Hot Plug Controllers on the three downstream
ports can be used to manage the hot plug event of its
associated slot.
Bridge
USB/SATA/GE
4
End Point
1
1
1
PEX 8509
Network
1
End
Point
Docking Station
Fully Compliant Power Management
For applications that require power management, the
ExpressLane PEX 8509 devices 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.
Figure 2. Docking Station
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