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

ID 790711
Date 7/08/2024
Public
Document Table of Contents

6.3.2. Prefix Format

The Prefix and Prefix Type fields carry the prefix information of the current TLP. The Prefix Present field indicates presence of prefix information. The Prefix Present field '0' indicates current TLP has no prefix associated with it. It is recommended to drive zero on Prefix and Prefix Type fields when Prefix Present is equal to '0'.

Note: The design supports one DW prefix per TLP in the current release.

The following figure shows PCIe* Prefix TLP Format.

Figure 50.  PCIe* TLP Prefix

The table below shows the mapping of PCIe TLP Prefix shown in the figure above on to the Tdata bus.

Table 42.   PCIe* TLP Prefix Mapping to Tdata Header Field
PCIe* TLP Prefix Bytes AXI-ST Tdata Header Byte Index
Prefix - Byte 3 Byte 16
Prefix - Byte 2 Byte 17
Prefix - Byte 1 Byte 18
Prefix Type - Byte 0 [Bits 4:0] Byte 19 [Bits 4:0]