Overview

Things should be made as simple as possible, but not any simpler.

Albert Einstein

This chapter looks more closely at the Physical Layer architecture of PCI Express. To start, the logical and electrical divisions of the Physical-Layer are investigated along with the functions that each performs. This takes into account several mechanisms such as scrambling, encoding, the preparation of data for transmission across the PCI Express link, and the signaling method used to transmit data. A large portion of this chapter focuses on the training and configuration of the PCI Express link by detailing the primary Physical Layer link training states. Finally, this chapter investigates the link responses to surprise insertion and removal of devices as well as the link s power management capabilities.