Cyclone® V Avalon® Memory-Mapped (Avalon-MM) Interface for PCI Express* Solutions User Guide

ID 683494
Date 10/24/2024
Public
Document Table of Contents

3.6. Link Capabilities

Table 14.  Link Capabilities  

Parameter

Value

Description

Link port number (Root Port only)

0x01

Sets the read-only value of the port number field in the Link Capabilities register. This parameter is for Root Ports only. It should not be changed.

Data link layer active reporting (Root Port only)

On/Off

Turn On this parameter for a Root Port, if the attached Endpoint supports the optional capability of reporting the DL_Active state of the Data Link Control and Management State Machine. For a hot-plug capable Endpoint (as indicated by the Hot Plug Capable field of the Slot Capabilities register), this parameter must be turned On. For Root Port components that do not support this optional capability, turn Off this option.

Not applicable for Avalon-MM or Avalon-MM DMA interfaces.

Surprise down reporting (Root Port only)

On/Off

When your turn this option On, an Endpoint supports the optional capability of detecting and reporting the surprise down error condition. The error condition is read from the Root Port.

Not applicable for Avalon-MM or Avalon-MM DMA interfaces.

Slot clock configuration

On/Off

When you turn this option On, indicates that the Endpoint or Root Port uses the same physical reference clock that the system provides on the connector. When Off, the IP core uses an independent clock regardless of the presence of a reference clock on the connector. This parameter sets the Slot Clock Configuration bit (bit 12) in the PCI Express Link Status register.