Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs

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ID 813652
Date 7/22/2024
Public
Document Table of Contents
Document Table of Contents x
1. About the Low Latency 40G Ethernet Intel® FPGA IP 2. Low Latency 40G Ethernet Intel® FPGA IP Parameters 3. Getting Started 4. Functional Description 5. Clocking and Reset Requirements 6. Interfaces and Signal Descriptions 7. Control, Status, and Statistics Register Descriptions 8. Comparison Between Various Low Latency 40G Ethernet Intel® FPGA IPs 9. Document Revision History for Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs
1. About the Low Latency 40G Ethernet Intel® FPGA IP x
1.1. Low Latency 40G Ethernet Intel® FPGA IP Supported Features 1.2. Low Latency 40G Ethernet Intel® FPGA IP Device Family and Speed Grade Support 1.3. Resource Utilization 1.4. Release Information
1.2. Low Latency 40G Ethernet Intel® FPGA IP Device Family and Speed Grade Support x
1.2.1. Low Latency 40G Ethernet Intel® FPGA IP Device Family Support 1.2.2. Low Latency 40G Ethernet Intel® FPGA IP Device Speed Grade Support
3. Getting Started x
3.1. Introduction to Intel® FPGA IP 3.2. Installing and Licensing Intel® FPGA IPs 3.3. Specifying the IP Parameters and Options 3.4. Simulating the IP 3.5. Generated File Structure 3.6. Integrating Your IP in Your Design 3.7. Testbench 3.8. Compiling the Full Design and Programming the FPGA
3.6. Integrating Your IP in Your Design x
3.6.1. Pin Assignments 3.6.2. Placement Settings
3.7. Testbench x
3.7.1. Understanding the Testbench Behavior
4. Functional Description x
4.1. Low Latency 40G Ethernet Intel® FPGA IP Functional Description 4.2. GTS Transceiver Configuration 4.3. TX MAC Datapath 4.4. RX MAC Datapath 4.5. Flow Control 4.6. Frame Status Checking 4.7. Link Fault Signaling Interface
4.3. TX MAC Datapath x
4.3.1. Preamble Pass-through/Insertion 4.3.2. Padding Bytes Insertion 4.3.3. Deficit Idle Count 4.3.4. TX CRC Insertion/Passthrough 4.3.5. TX Avalon® Streaming Filter 4.3.6. TX PCS 4.3.7. PMA
4.4. RX MAC Datapath x
4.4.1. RX Preamble Pass-through or Removal 4.4.2. RX CRC Checking and Dynamic Option to Forward 4.4.3. Strict SFD/Preamble Checking 4.4.4. RX PCS Functional Description
4.5. Flow Control x
4.5.1. TX Pause/PFC Flow Control Transmission 4.5.2. XON/XOFF Pause Frames
4.6. Frame Status Checking x
4.6.1. Frame Type Checking 4.6.2. Length Checking
5. Clocking and Reset Requirements x
5.1. Reset Requirements
6. Interfaces and Signal Descriptions x
6.1. TX MAC Interface to User Logic 6.2. RX MAC Interface to User Logic 6.3. GTS Transceivers Signals 6.4. GTS 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 6.10. GTS Reset Sequencer Intel® FPGA IP
7. Control, Status, and Statistics Register Descriptions x
7.1. PHY Registers 7.2. TX MAC Registers 7.3. RX MAC Registers 7.4. Pause/PFC Flow Control 7.5. Statistics Counters 7.6. Shadow Register
1. About the Low Latency 40G Ethernet Intel® FPGA IP
2. Low Latency 40G Ethernet Intel® FPGA IP Parameters
3. Getting Started
4. Functional Description
5. Clocking and Reset Requirements
6. Interfaces and Signal Descriptions
7. Control, Status, and Statistics Register Descriptions
8. Comparison Between Various Low Latency 40G Ethernet Intel® FPGA IPs
9. Document Revision History for Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs

4.1. Low Latency 40G Ethernet Intel® FPGA IP Functional Description

The Low Latency 40G Ethernet Intel® FPGA IP for Agilex™ 5 devices implements an Ethernet MAC in accordance with the IEEE 802.3 Ethernet Standard. The IP implements an Ethernet PCS and PMA (PHY) that handles the frame encapsulation and flow of data between a client logic and Ethernet network.

This section describes the Low Latency 40G Ethernet Intel® FPGA IP MAC and PCS IP using Agilex™ 5 devices with GTS transceiver.
Figure 6.  Low Latency 40G Ethernet Intel® FPGA IP Block Diagram

In the TX direction, the MAC processes the received client frames, assembles packets, and sends them to the PHY. The MAC carries out the following tasks:

  • Accepts client frames.
  • Inserts the inter-packet gap (IPG), preamble, start of frame delimiter (SFD), padding, and CRC bits before passing them to PHY.
  • Adds the CRC bits if enabled.
  • Updates statistics counters if enabled.
  • The PHY encodes MAC frames for reliable transmission over the media to the remote end.

In the RX path, the PHY receives incoming packets and passes these data in frames to the PCS that sends them to the MAC. The MAC completes the following tasks:

  • Performs CRC and malformed packet checks.
  • Updates statistics counters if enabled.
  • Strips out the CRC, preamble, and SFD.
  • Passes the remainder of the frame to the client.

In preamble pass-through mode, the MAC passes on the preamble and SFD to the client instead of stripping them out. In RX CRC pass-through mode, the MAC passes on the CRC bytes to the client and asserts the end-of-packet signal in the same clock cycle as the final CRC byte.

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