F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide

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ID 720985
Date 4/01/2022
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Document Table of Contents
Document Table of Contents x
1. About the F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide 2. Low Latency Ethernet 10G MAC Intel® FPGA IP Overview 3. Getting Started 4. Functional Description 5. Low Latency Ethernet 10G MAC Intel® FPGA IP Parameters 6. Interface Signals 7. Configuration Registers 8. Document Revision History for the F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide
2. Low Latency Ethernet 10G MAC Intel® FPGA IP Overview x
2.1. Release Information 2.2. Features 2.3. Low Latency Ethernet 10G MAC Operating Modes 2.4. Device Family Support 2.5. Performance and Resource Utilization
2.5. Performance and Resource Utilization x
2.5.1. Resource Utilization 2.5.2. TX and RX Latency
3. Getting Started x
3.1. Introduction to Intel® FPGA IP Cores 3.2. Installing and Licensing Intel® FPGA IP Cores 3.3. Specifying the IP Core Parameters and Options ( Intel® Quartus® Prime Pro Edition) 3.4. Generated File Structure 3.5. Simulating Intel® FPGA IP Cores 3.6. Upgrading the Low Latency Ethernet 10G MAC Intel® FPGA IP Core 3.7. Low Latency Ethernet 10G MAC Intel® FPGA IP Design Examples
3.6. Upgrading the Low Latency Ethernet 10G MAC Intel® FPGA IP Core x
3.6.1. Designing Considerations for the F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP
3.6.1. Designing Considerations for the F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP x
3.6.1.1. Timing Constraints
3.6.1.1. Timing Constraints x
3.6.1.1.1. Pseudo-Static CSR Fields 3.6.1.1.2. Clock Crosser 3.6.1.1.3. Dual Clock FIFO
3.7. Low Latency Ethernet 10G MAC Intel® FPGA IP Design Examples x
3.7.1. Low Latency Ethernet 10G MAC Intel® FPGA IP Design Example for Intel® Agilex™ Devices
4. Functional Description x
4.1. Architecture 4.2. Interfaces 4.3. Frame Types 4.4. TX Datapath 4.5. RX Datapath 4.6. Flow Control 4.7. Reset Requirements 4.8. Supported PHYs 4.9. XGMII Error Handling (Link Fault)
4.4. TX Datapath x
4.4.1. Padding Bytes Insertion 4.4.2. Address Insertion 4.4.3. CRC-32 Insertion 4.4.4. XGMII Encapsulation 4.4.5. Inter-Packet Gap Generation and Insertion 4.4.6. XGMII Transmission 4.4.7. TX Promiscuous (Transparent) Mode 4.4.8. TX Timing Diagrams
4.4.4. XGMII Encapsulation x
4.4.4.1. Transmit Path
4.5. RX Datapath x
4.5.1. XGMII Decapsulation 4.5.2. CRC Checking 4.5.3. Address Checking 4.5.4. Frame Type Checking 4.5.5. CRC and Padding Bytes Removal 4.5.6. Frame Length Checking 4.5.7. Overflow Handling 4.5.8. RX Promiscuous (Transparent) Mode 4.5.9. RX Timing Diagrams
4.5.3. Address Checking x
4.5.3.1. Unicast Frame Filtering 4.5.3.2. Multicast Frame Filtering
4.5.4. Frame Type Checking x
4.5.4.1. Malformed RX Packets 4.5.4.2. CRC Error 4.5.4.3. Address Check Error
4.5.6. Frame Length Checking x
4.5.6.1. Frame Length 4.5.6.2. Payload Length
4.6. Flow Control x
4.6.1. IEEE 802.3 Flow Control
4.6.1. IEEE 802.3 Flow Control x
4.6.1.1. Pause Frame Reception 4.6.1.2. Pause Frame Transmission
6. Interface Signals x
6.1. Clock and Reset Signals 6.2. Speed Selection Signal 6.3. Error Correction Signals 6.4. Avalon® Memory-Mapped Interface Programming Signals 6.5. Avalon® Streaming Data Interfaces 6.6. Avalon® Streaming Flow Control Signals 6.7. Avalon® Streaming Status Interface 6.8. PHY-side Interfaces
6.5. Avalon® Streaming Data Interfaces x
6.5.1. Avalon® Streaming TX Data Interface Signals 6.5.2. Avalon® Streaming RX Data Interface Signals 6.5.3. Avalon® Streaming Data Interface Clocks
6.7. Avalon® Streaming Status Interface x
6.7.1. Avalon® Streaming Interface TX Status Signals 6.7.2. Avalon® Streaming Interface RX Status Signals
6.8. PHY-side Interfaces x
6.8.1. XGMII TX Signals 6.8.2. XGMII RX Signals
7. Configuration Registers x
7.1. Register Map 7.2. Register Access Definition 7.3. Primary MAC Address 7.4. TX Configuration and Status Registers 7.5. Flow Control Registers 7.6. RX Configuration and Status Registers 7.7. ECC Registers 7.8. Statistics Registers
1. About the F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide
2. Low Latency Ethernet 10G MAC Intel® FPGA IP Overview
3. Getting Started
4. Functional Description
5. Low Latency Ethernet 10G MAC Intel® FPGA IP Parameters
6. Interface Signals
7. Configuration Registers
8. Document Revision History for the F-Tile Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide

3.6.1.1.2. Clock Crosser

Clock crossers perform multi-bit signals crossing from one clock domain to another.

The working principle of the clock crosser is to let the crossed-over data stabilize first before indicating that the data is valid in the latched clock domain. Using such structure, the data bits must not skew for more than one latched clock period. The timing constraint file applies a common timing check over all the clock crossers irrespective of their latched clock domain. This is over-pessimistic for signals crossing into the CSR clock, but there are no side-effects, like significant run-time impact and false violations, during the internal testing. If your design runs into clock crosser timing violation paths within the IP and the latched clock domain is csr_clk, you can dismiss the violation manually or by editing the .sdc file if the violation is less than one csr_clk period.

The timing constraint file uses the set_net_delay to constraint the fitter placement and set_max_skew to perform timing check on the paths. For a project with very high device utilization, Intel recommends that you implement addition steps like floor planning or Logic Lock to aid the place-and-route process. The additional steps can give a more consistent timing closure along these paths instead of only relying on the set_net_delay.

A caveat of using set_max_skew is that it does not analyze whether the insertion delay of the path in concern exceeds a limit. In other words, a path could meet skew requirement but have longer than expected insertion delay. If this is not checked, it may cause functional failure in certain latency-sensitive paths. Therefore, a custom script (alt_em10g32_clock_crosser_timing_info.tcl) is available for you to check that the round-trip clock crosser delay is within expectation. To use this script, manually add it to the user flow and run it. To ensure that the IP core operates correctly, the results must be positive (no error).

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