GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 1/24/2025
Public
Document Table of Contents

5.2.2.1. PCIe0/PCIe1 Configuration, Debug and Extension Options

Table 30.   GTS AXI Streaming IP Parameters: PCIe* 0/ PCIe* 1 Configuration, Debug and Extension Options Tab
Parameter Value Default Value Description
Gen 3 Requested equalization far-end TX preset vector 0 – 0x7ff 0x00000124

Specifies the Gen 3 requested phase 2/3 far-end TX preset vector.

Gen 4 Requested equalization far-end TX preset vector 0 – 0x7ff 0x00000160

Specifies the Gen 4 requested phase 2/3 far-end TX preset vector. Choosing a value different from the default is not recommended for most designs.

Predetermined number of lanes
  • 4
  • 2
  • 1
Maximum link width

Defines the number of lanes which are connected and good.

Used to limit the effective link width to ignore broken or unused lanes that detect a receiver. Indicates the number of lanes to check for exit from Electrical Idle in Polling.Active and L2.Idle. It is possible that the LTSSM might detect a receiver on a bad or broken lane during the Detect Substate.

However, it is also possible that such a lane might also fail to exit Electrical Idle and therefore prevent a valid link from being configured. This value is referred to as the Predetermined Number of Lanes in section 4.2.6.2.1 of the PCI Express Base Specification.

When you have unused lanes in the system, you must change the value in this register to reflect the number of lanes. For instance, if you find that one of the used lanes is bad, then you must reduce the value of Predetermined number of lanes.