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

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ID 813652
Date 11/25/2024
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 the 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 Datapath 4.4. RX Datapath 4.5. Flow Control 4.6. Link Fault Signaling Interface
4.3. TX Datapath x
4.3.1. TX MAC 4.3.2. TX PCS Block Encoder Scrambler Alignment Marker Insertion Block Distributor 4.3.3. PMA
4.3.1. TX MAC x
4.3.1.1. Preamble Insertion 4.3.1.2. Frame Padding 4.3.1.3. Inter-Packet Gap Generation and Insertion 4.3.1.4. Frame Check Sequence (CRC-32) Insertion 4.3.1.5. TX Avalon® Streaming Filter
4.4. RX Datapath x
4.4.1. RX MAC 4.4.2. RX PCS
4.4.1. RX MAC x
4.4.1.1. IP Core Preamble Processing 4.4.1.2. IP Core CRC Checking and Dynamic Forwarding 4.4.1.3. IP Core Strict SFD Checking 4.4.1.4. Length/Type Field Processing
4.4.1.4. Length/Type Field Processing x
4.4.1.4.1. Frame Type Checking 4.4.1.4.2. Length Checking
4.5. Flow Control x
4.5.1. TX Pause/PFC Flow Control Transmission 4.5.2. XON/XOFF Pause Frames
5. Clocking and Reset Requirements x
5.1. Clocks 5.2. 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. TX PCS Interface to User Logic 6.4. RX PCS Interface to User Logic 6.5. GTS Transceivers Signals 6.6. GTS Transceiver Reconfiguration Signals 6.7. Avalon® Memory-Mapped Management Interface 6.8. Miscellaneous Status and Debug Signals 6.9. Reset Signals 6.10. Clocks 6.11. Flow Control Interface 6.12. 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 the Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs

4.3.2. TX PCS

Figure 7. TX PCS

In MAC, PCS, and PMA variant, the TX PCS module is an internal block and this block is connected to the internal TX MAC block. Whereas in PCS and PMA variant, the MII data and control bus along with the other PCS control and status signals are provided as the user interface.

The TX PCS has four main components:

Block Encoder

The block encoder takes the 64-bit data blocks and 8-bit control blocks and encodes them into 66 bit encoded blocks. The TX PCS encodes two blocks per clock cycle.

Scrambler

The TX PCS scrambler takes two encoded blocks per clock cycles and scrambles them and produces two scrambled data blocks per clock cycle.

Alignment Marker Insertion

The alignment marker insertion blocks are used to insert an alignment marker on each virtual lane every 16,384 data blocks.

In the case of MAC, PCS, and PMA variant, the alignment marker is inserted inside the IP, however in the case of PCS and PMA mode, the user logic should indicate the AM location by asserting the tx_mii_am interface signal. The user logic must hold the tx_mii_am signal asserted for 2 clk_tx_mii consecutive clock cycles, counting only the valid cycles, to drive the insertion of an alignment marker. A valid cycle is one in which tx_mii_valid has the value of 1.

The am_period indicated with the number of valid clock cycles from the deassertion of tx_mii_am (alignment marker insertion bit signal) to the reassertion of tx_mii_am. For normal operation of the Ethernet link, you must ensure that the value of am_period is 32768 clock cycles (clk_tx_mii 312.5 MHz).

While you hold the value of the tx_mii_am signal at 1, you must freeze the values of both tx_mii_d and tx_mii_c.

Block Distributor

The block distributor takes the scrambled data blocks and alignment marker and distributes them round robin to the four virtual lanes.

Level Two Title