PCI Express System Architecture

Link Initialization and Training Overview

General

Link initialization and training is a Physical Layer control process that configures and initializes a device's Physical Layer, port, and associated Link so that normal packet traffic can proceed on the Link. This process is automatically initiated after reset without any software involvement. A sub-set of the Link training and initialization process, referred to as Link re-training, is initiated automatically as a result of a wakeup event from a low power mode, or due to an error condition that renders the Link inoperable. The Link Training and Status State Machine (LTSSM) is the Physical Layer sub-block responsible for the Link training and initialization process (see Figure 14-1).X

Figure 14-1. ...