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

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ID 683426
Date 4/09/2024
Public
Document Table of Contents
Document Table of Contents x
1. About LL Ethernet 10G MAC 2. Getting Started 3. LL Ethernet 10G MAC Intel® FPGA IP Design Examples 4. Functional Description 5. Configuration Registers 6. Interface Signals 7. Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide Archives 8. Document Revision History for the Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide
1. About LL Ethernet 10G MAC x
1.1. Features 1.2. Release Information 1.3. Low Latency Ethernet 10G MAC Operating Modes 1.4. Device Family Support 1.5. Performance and Resource Utilization
1.1. Features x
1.1.1. LL Ethernet 10G MAC and Legacy 10-Gbps Ethernet MAC
1.5. Performance and Resource Utilization x
1.5.1. Resource Utilization 1.5.2. TX and RX Latency
2. Getting Started x
2.1. Introduction to Intel® FPGA IP Cores 2.2. Installing and Licensing Intel® FPGA IP Cores 2.3. Specifying the IP Core Parameters and Options ( Quartus® Prime Pro Edition) 2.4. IP Core Generation Output ( Quartus® Prime Pro Edition) 2.5. Files Generated for Intel IP Cores (Legacy Parameter Editor) 2.6. Simulating Intel® FPGA IP Cores 2.7. Creating a Signal Tap Debug File to Match Your Design Hierarchy 2.8. Parameter Settings for the Low Latency Ethernet 10G MAC Intel® FPGA IP Core 2.9. Upgrading the Low Latency Ethernet 10G MAC Intel® FPGA IP Core 2.10. Design Considerations for the Low Latency Ethernet 10G MAC Intel® FPGA IP Core
2.10. Design Considerations for the Low Latency Ethernet 10G MAC Intel® FPGA IP Core x
2.10.1. Migrating from Legacy Ethernet 10G MAC to LL Ethernet 10G MAC 2.10.2. Timing Constraints 2.10.3. Jitter on PLL Clocks
2.10.1. Migrating from Legacy Ethernet 10G MAC to LL Ethernet 10G MAC x
2.10.1.1. Migration—32-bit Datapath on Avalon® Streaming Interface 2.10.1.2. Migration—Maintains 64-bit on Avalon® Streaming Interface
2.10.2. Timing Constraints x
2.10.2.1. Pseudo-Static CSR Fields 2.10.2.2. Clock Crosser 2.10.2.3. Dual Clock FIFO
3. LL Ethernet 10G MAC Intel® FPGA IP Design Examples x
3.1. LL Ethernet 10G MAC Intel® FPGA IP Design Example for Stratix® 10 Devices 3.2. LL Ethernet 10G MAC Intel® FPGA IP Design Example for Arria® 10 Devices 3.3. LL Ethernet 10G MAC Intel® FPGA IP Design Example for Cyclone® 10 GX 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) 4.10. IEEE 1588v2
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. Unidirectional Feature 4.4.8. TX Timing Diagrams
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. Length Checking 4.5.6. CRC and Padding Bytes Removal 4.5.7. Overflow Handling 4.5.8. RX Timing Diagrams
4.5.5. Length Checking x
4.5.5.1. Frame Length 4.5.5.2. Payload Length
4.6. Flow Control x
4.6.1. IEEE 802.3 Flow Control 4.6.2. Priority-Based 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
4.6.2. Priority-Based Flow Control x
4.6.2.1. PFC Frame Reception 4.6.2.2. PFC Frame Transmission
4.8. Supported PHYs x
4.8.1. 10GBASE-R Register Mode
4.10. IEEE 1588v2 x
4.10.1. Architecture 4.10.2. TX Datapath 4.10.3. RX Datapath 4.10.4. Frame Format
4.10.4. Frame Format x
4.10.4.1. PTP Packet in IEEE 802.3 4.10.4.2. PTP Packet over UDP/IPv4 4.10.4.3. PTP Packet over UDP/IPv6
5. Configuration Registers x
5.1. Register Map 5.2. Register Access Definition 5.3. Primary MAC Address 5.4. MAC Reset Control Register 5.5. TX Configuration and Status Registers 5.6. Flow Control Registers 5.7. Unidirectional Control Registers 5.8. RX Configuration and Status Registers 5.9. Timestamp Registers 5.10. ECC Registers 5.11. Statistics Registers
5.1. Register Map x
5.1.1. Mapping 10-Gbps Ethernet MAC Registers to LL Ethernet 10G MAC Registers
5.9. Timestamp Registers x
5.9.1. Calculating Timing Adjustments
6. Interface Signals x
6.1. Clock and Reset Signals 6.2. Speed Selection Signal 6.3. Error Correction Signals 6.4. Unidirectional Signals 6.5. Avalon® Memory-Mapped Interface Programming Signals 6.6. Avalon® Streaming Data Interfaces 6.7. Avalon® Streaming Flow Control Signals 6.8. Avalon® Streaming Status Interface 6.9. PHY-side Interfaces 6.10. IEEE 1588v2 Interfaces
6.6. Avalon® Streaming Data Interfaces x
6.6.1. Avalon® Streaming TX Data Interface Signals 6.6.2. Avalon® Streaming RX Data Interface Signals 6.6.3. Avalon® Streaming Data Interface Clocks
6.8. Avalon® Streaming Status Interface x
6.8.1. Avalon® Streaming Interface TX Status Signals 6.8.2. Avalon® Streaming Interface RX Status Signals
6.9. PHY-side Interfaces x
6.9.1. XGMII TX Signals 6.9.2. XGMII RX Signals 6.9.3. GMII TX Signals 6.9.4. GMII RX Signals 6.9.5. MII TX Signals 6.9.6. MII RX Signals
6.10. IEEE 1588v2 Interfaces x
6.10.1. IEEE 1588v2 Egress TX Signals 6.10.2. IEEE 1588v2 Ingress RX Signals 6.10.3. IEEE 1588v2 Interface Clocks
1. About LL Ethernet 10G MAC
2. Getting Started
3. LL Ethernet 10G MAC Intel® FPGA IP Design Examples
4. Functional Description
5. Configuration Registers
6. Interface Signals
7. Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide Archives
8. Document Revision History for the Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide

2.10.2.2. 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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