Board and System Design Applications

The ExpressLane PEX 8114 can be used on PCI Express-

based motherboards or embedded systems to connect legacy

PCI or PCI-X slots or devices. In addition, the bridge can be

used in add-on cards and mezzanine boards in either forward

or reverse bridge mode.

Motherboards

The simple design and small footprint of the ExpressLane

PEX 8114 make it an ideal bridge solution for the

motherboard (see Figure 1), providing for PCI or PCI-X slot

connectivity and for interface to legacy native PCI or PCI-X

silicon I/O components.

Figure 1. Forward Bridge on Motherboard

In addition, the ExpressLane PEX 8114 is ideal for enabling

PCI Express slot connectivity on motherboards with existing

PCI or PCI-X chipsets (see Figure 2). The reverse bridge

function including reverse bridge root registers means

customers can upgrade existing designs without changing their

choice of CPU chipset.

Figure 2. Reverse Bridge on Motherboard

Adapter Boards-Forward Bridge

In Forward Mode (see Figure 3), the ExpressLane PEX 8114

can be used to quickly upgrade legacy PCI or PCI-X adapter

board designs to be compatible with PCI Express standard

interface slots.

Figure 3. Forward Mode

Adapter Boards-Reverse Bridge

The ExpressLane PEX 8114 supports Reverse Mode bridging

(see Figure 5), enabling state-of-the-art PCI Express silicon to

be used with legacy PCI or PCI-X parallel busses. Designers

can utilize the latest LAN, SAN or NAS I/O silicon

architectures and features while providing the capability to

bridge backwards to widely entrenched legacy slots and

backplanes. Reverse bridging allows the host processor to

reside out on the PCI or PCI-X bus; the bridge will accept

configuration cycles from the PCI/PCI-X side and manage the

local PCI Express interface as a secondary entity within the

PCI software model.

Figure 5. Reverse Mode