Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Public
Document Table of Contents

4.4. PCI Express (PCIe)—Gen1, Gen2, and Gen3

The PCIe specification (version 3.0) provides implementation details for a PCIe-compliant physical layer device at Gen1 (2.5 Gbps), Gen2 (5 Gbps), and Gen3 (8 Gbps) signaling rates.

The devices have built-in PCIe hard IP blocks to implement the PHY MAC layer, data link layer, and transaction layer of the PCIe protocol stack. Up to four PCIe hard IP block reside within a Stratix V device. If you enable the PCIe hard IP block, the transceiver interfaces with the hard IP block. Otherwise, the transceiver interfaces directly through the PIPE interface. You must then implement a Soft-IP MAC layer, data link layer, and transaction layer to the PIPE interface from the core fabric.

You can configure the transceivers in a PCIe functional configuration using one of the following methods:

  • Stratix V Hard IP for PCI Express
  • PHY IP core for PCI Express (PIPE)

The following table shows the two methods supported by transceivers in a PCIe functional configuration.

Table 34.  Support for Transceivers
Support Stratix V Hard IP for PCI Express PHY IP Core for PCI Express (PIPE)
Gen1, Gen2, and Gen3 data rates Yes Yes
MAC, data link, and transaction layer Yes
Transceiver interface Hard IP through PIPE 3.0-like

PIPE 2.0 for Gen1 and Gen2

PIPE 3.0-like for Gen3 with Gen1/Gen2 support

To implement the PHY IP Core for PCI Express (PIPE) configuration, instantiate the PHY IP Core for PCI Express (PIPE) in the IP Catalog, under PCI Express in the Interfaces menu.

Stratix V transceivers support x1, x2, x4, and x8 lane configurations. In a PCIe x1 configuration, the PCS and PMA blocks of each channel are clocked and reset independently. PCIe x2, x4, and x8 configurations support channel bonding for two-lane, four-lane, and eight-lane PCIe links. In these bonded channel configurations, the PCS and PMA blocks of all bonded channels share common clock and reset signals.