Low Latency 40-Gbps Ethernet Intel® FPGA IP User Guide: Stratix® 10

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ID 683600
Date 5/31/2024
Public
Document Table of Contents
Document Table of Contents x
1. About the Low Latency 40G Ethernet Core 2. Stratix® 10 Low Latency 40G Ethernet IP Core Parameters 3. Getting Started 4. Functional Description 5. Reset 6. Interfaces and Signal Descriptions 7. Control, Status, and Statistics Register Descriptions 8. Debugging the Link 9. Ethernet Toolkit Overview 10. Stratix® 10 Low Latency 40GbE IP Core User Guide Archives 11. Differences Between Stratix® 10 Low Latency 40G Ethernet IP Core and Low Latency 40G Ethernet IP Core That Targets an Arria 10 Device 12. Document Revision History for Stratix® 10 Low Latency 40G Ethernet User Guide
1. About the Low Latency 40G Ethernet Core x
1.1. Stratix® 10 LL 40GbE IP Core Supported Features 1.2. Stratix® 10 LL 40GbE Core Device Family and Speed Grade Support 1.3. Resource Utilization 1.4. Release Information
1.2. Stratix® 10 LL 40GbE Core Device Family and Speed Grade Support x
1.2.1. Device Family Support 1.2.2. Stratix® 10 LL 40GbE IP Core Device Speed Grade Support
3. Getting Started x
3.1. Installing and Licensing Intel® FPGA IP Cores 3.2. Specifying the Stratix® 10 LL 40GbE IP Core Parameters and Options 3.3. Simulating the IP Core 3.4. Generated File Structure 3.5. Integrating Your IP Core in Your Design 3.6. Stratix® 10 Low Latency 40G Ethernet IP Core Testbench 3.7. Compiling the Full Design and Programming the FPGA
3.5. Integrating Your IP Core in Your Design x
3.5.1. Pin Assignments 3.5.2. Adding the Transceiver PLL 3.5.3. Clock Requirements for 40GBASE-KR4/CR4 Variations 3.5.4. Adding the External TX MAC PLL 3.5.5. Placement Settings for the Stratix® 10 Low Latency 40G Ethernet Core
3.6. Stratix® 10 Low Latency 40G Ethernet IP Core Testbench x
3.6.1. Understanding the Testbench Behavior
4. Functional Description x
4.1. Stratix® 10 LL 40GbE Core Functional Description 4.2. User Interface to Ethernet Transmission
4.1. Stratix® 10 LL 40GbE Core Functional Description x
4.1.1. Stratix® 10 LL 40GbE Core TX MAC Datapath 4.1.2. Stratix® 10 LL 40GbE Core RX MAC Datapath 4.1.3. Link Fault Signaling Interface 4.1.4. Stratix® 10 Low Latency 40GBASE-KR4 IP Core Variations
4.1.1. Stratix® 10 LL 40GbE Core TX MAC Datapath x
4.1.1.1. Frame Padding 4.1.1.2. Preamble Insertion 4.1.1.3. Inter-Packet Gap Generation and Insertion 4.1.1.4. Frame Check Sequence (CRC-32) Insertion
4.1.2. Stratix® 10 LL 40GbE Core RX MAC Datapath x
4.1.2.1. IP Core Preamble Processing 4.1.2.2. IP Core Strict SFD Checking 4.1.2.3. Length/Type Field Processing 4.1.2.4. RX CRC Checking and Dynamic Forwarding
4.1.2.3. Length/Type Field Processing x
4.1.2.3.1. Length Checking
4.2. User Interface to Ethernet Transmission x
4.2.1. Order of Transmission 4.2.2. Bit Order For TX and RX Datapaths
6. Interfaces and Signal Descriptions x
6.1. TX MAC Interface to User Logic 6.2. RX MAC Interface to User Logic 6.3. Transceivers Signals 6.4. Transceiver Reconfiguration Signals 6.5. Avalon® Memory-Mapped Management Interface 6.6. Miscellaneous Status and Debug Signals 6.7. Reset Signals 6.8. Clocks 6.9. Flow Control Interface
7. Control, Status, and Statistics Register Descriptions x
7.1. Stratix® 10 LL 40GBASE-KR4/CR4 Registers 7.2. PHY Registers 7.3. TX MAC Registers 7.4. RX MAC Registers 7.5. Statistics Registers
7.5. Statistics Registers x
7.5.1. TX Statistics Registers 7.5.2. RX Statistics Registers
9. Ethernet Toolkit Overview x
9.1. Features
1. About the Low Latency 40G Ethernet Core
2. Stratix® 10 Low Latency 40G Ethernet IP Core Parameters
3. Getting Started
4. Functional Description
5. Reset
6. Interfaces and Signal Descriptions
7. Control, Status, and Statistics Register Descriptions
8. Debugging the Link
9. Ethernet Toolkit Overview
10. Stratix® 10 Low Latency 40GbE IP Core User Guide Archives
11. Differences Between Stratix® 10 Low Latency 40G Ethernet IP Core and Low Latency 40G Ethernet IP Core That Targets an Arria 10 Device
12. Document Revision History for Stratix® 10 Low Latency 40G Ethernet User Guide

4.1.1.4. Frame Check Sequence (CRC-32) Insertion

The TX MAC computes and inserts a CRC32 checksum in the transmitted MAC frame. The frame check sequence (FCS) field contains a 32-bit CRC value. The MAC computes the CRC32 over the frame bytes that include the source address, destination address, length, data, and pad (if applicable). The CRC checksum computation excludes the preamble, SFD, and FCS. The encoding is defined by the following generating polynomial: 

FCS(X) = X32 +X26 +X23 +X22 +X16 +X12 +X11 +X10 +X8 +X7 +X5 +X4 +X2 +X1 +1

CRC bits are transmitted with MSB (X32) first.

You can configure your IP core TX MAC to implement TX CRC insertion or not, by turning Enable TX CRC insertion on or off in the IP core parameter editor. By default, the CRC insertion feature is enabled.

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