Overview

As the system designer, you must be able to make informed tradeoffs that help you to meet the signal integrity requirements of the specification while also achieving the design targets of your particular system. The practical guidelines included in this and in subsequent chapters contain the information that you need in order to make those informed tradeoffs.

The examples and topologies examined in the next few chapters focus largely on standard desktop system implementations of PCI Express . However, the general guidelines and suggestions presented here are applicable to a variety of designs. The range of implementations includes server backplanes, mobile systems, or even custom applications.

In addition to presenting general guidelines, this chapter addresses system design details with respect to add-in card and ExpressCard -based systems. For details on the actual designs for the add-in cards and the ExpressCard modules themselves, see Chapter 7, "Add-in Cards and ExpressCard Modules."

To serve the needs of diverse applications, several variations of the PCI Express Base Specification (PCI-SIG 2004a) are available, with more on the horizon. For example, mobile systems might follow the Mobile Graphics Low-Power Addendum to the PCI Express Base Specification (PCI-SIG 2003b) which allows for reduced signal output swings in low loss interconnect systems. Desktop, mobile, and server systems that interact with PCI Express add-in cards and ExpressCard modules must follow the requirements set forth in the PCI Express Card Electromechanical (CEM)...