(PCIe to PCI bridge). The four ports in the PEX8604 provide

connectivity between the processor to up to three peripherals

each via an x1 connection. This usage model provides

connectivity within a set top box between the control

processor and the various endpoints.

Figure 3. Set Top Box

Mobile Wireless Adaptor

PEX 8604 devices can be used in applications where low

power consumption is of importance as is the case in mobile

applications. An example of a mobile wireless adapter card is

shown in Figure 4.

Figure 4. Mobile Wireless Adaptor

Embedded Mezzanine Module

The PEX 8604 is well suited for mezzanine module

applications. Figure 5 shows that the mezzanine card has a

local processor and a local PCIe hierarchy with the PEX8604

and multiple endpoints. Additionally, the non-transparent

port in the PEX8604 allows the mezzanine to interface with

the main CPU in the Baseboard as well as other mezzanine

modules.

Figure 5. PCI Express Mezzanine Module

Intelligent Adapter Card

The PEX 8604 supports the non-transparency feature.

Figure 6 illustrates a host system using an intelligent adapter

card.

Figure 6. Intelligent Adapter Usage

In this figure, the CPU on the adapter card is isolated from the

host CPU. The PEX 8604 non-transparent port allows the two

CPUs to be isolated but communicate with each other through

various registers that are designed in the PEX 8604 for that

purpose. The host CPU can dynamically re-assign both the

upstream port and the non-transparent port of PEX 8604

allowing the system to be reconfigured.

Active-Standby Failover Model

The PEX 8604 supports applications requiring dual host, host

failover applications through the non-transparency (NTB)

feature. Figure 7 illustrates a dual host system with an active

and standby processor configuration.

The redundancy of the host and the fabric can be achieved

through many possible configurations using NTB function of

PEX 8604. In the configuration shown below Processor A is

the primary active host of the PCI Express system. Processor

B acts as the backup Host. In the case of a failure on Processor

A, application software is instructed to migrate the PCI

Express system to Processor B. Consequently, Processor B

becomes the active host and Processor A can be replaced as

the backup Host.

Figure 7. Active-Standby Control Plane