DS506 Datasheet, PDF (4/19 Pages) Xilinx, Inc – LogiCORE IP Endpoint v3.7

LogiCORE IP Endpoint v3.7 for PCI Express^®
Logic Modules
The logic modules handle the functionality related to each of the layers defined by the PCI Express Base
Specification. The functions of these modules include
• Generating and processing of TLPs
• Flow-control management
• Initialization and power management functions
• Data protection
• Error checking and retry functions
• Physical link interface initialization
• Maintenance and status tracking
• Serialization, de-serialization and other circuitry for interface operation
Each of the logic models, introduced in the "Functional Description," page 3, are defined in the follow-
ing sections.
Physical Layer Module
The Physical Layer exchanges information with the Data Link Layer in an implementation-specific for-
mat. This layer is responsible for converting information received from the Data Link Layer into an
appropriate serialized format and transmitting it across the PCI Express Link at a frequency and width
compatible with the remote device.
Data Link Layer Module
The Data Link Layer acts as an intermediate stage between the Transaction Layer and the Physical
Layer. Its primary responsibility is to provide a reliable mechanism for the exchange of Transaction
Layer Packets (TLPs) between the two Components on a Link.
Services provided by the Data Link Layer include data exchange (TLPs), error detection and recovery,
initialization services and the generation and consumption of Data Link Layer Packets (DLLPs). DLLPs
are the mechanism used to transfer information between Data Link Layers of two directly connected
Components on the Link. They are used for conveying information such as Flow Control and TLP
acknowledgments.
Transaction Layer Module
The upper layer of the PCI Express architecture is the Transaction Layer. The primary goal of the Trans-
action Layer is the assembly and disassembly of Transaction Layer Packets (TLPs). Packets are formed
in the Transaction and Data Link Layers to carry the information from the transmitting component to
the receiving component. TLPs are used to communicate transactions, such as read and write, as well as
certain types of events. To maximize the efficiency of communication between devices, the Transaction
Layer implements a pipelined, full split-transaction protocol, manages credit-based flow control of
TLPs, and offers optional support for data poisoning.
Configuration Management Module
The Configuration Management Module supports generation and reception of System Management
Messages by communicating with the other modules and the user application. This module contains
the device configuration space and other system functions. The CMM implements PCI/PCI-Express
power management capabilities, and facilitates exchange of power management messages, including
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DS506 April 19, 2010
Product Specification