Low Latency 40- and 100-Gbps Ethernet MAC and PHY MegaCore Function User Guide

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ID 683628
Date 12/28/2017
Public
Document Table of Contents
Document Table of Contents x
1. About the Low Latency 40- and 100-Gbps Ethernet MAC and PHY IP Core 2. Getting Started 3. Functional Description 4. Debugging the Link A. Arria 10 10GBASE-KR Registers B. Differences Between Low Latency 40-100GbE IP Core and 40-100GbE IP Core v15.1 C. Additional Information
1. About the Low Latency 40- and 100-Gbps Ethernet MAC and PHY IP Core x
1.1. Low Latency 40- and 100-Gbps Ethernet MAC and PHY IP Core Supported Features 1.2. Low Latency 40-100GbE IP Core Device Family and Speed Grade Support 1.3. IP Core Verification 1.4. Performance and Resource Utilization 1.5. Release Information
1.2. Low Latency 40-100GbE IP Core Device Family and Speed Grade Support x
1.2.1. Device Family Support 1.2.2. Low Latency 40-100GbE IP Core Device Speed Grade Support
1.3. IP Core Verification x
1.3.1. Simulation Environment 1.3.2. Compilation Checking 1.3.3. Hardware Testing
1.4. Performance and Resource Utilization x
1.4.1. Stratix V Resource Utilization for Low Latency 40-100GbE IP Cores 1.4.2. Arria 10 Resource Utilization for Low Latency 40-100GbE IP Cores
2. Getting Started x
2.1. Installation and Licensing for LL 40-100GbE IP Core for Stratix V Devices 2.2. Licensing IP Cores 2.3. Specifying the Low Latency 40-100GbE IP Core Parameters and Options 2.4. IP Core Parameters 2.5. Files Generated for Stratix V Variations 2.6. Files Generated for Arria 10 Variations 2.7. Integrating Your IP Core in Your Design 2.8. Low Latency 40-100GbE IP Core Testbenches 2.9. Simulating the Low Latency 40‑100GbE IP Core With the Testbenches 2.10. Compiling the Full Design and Programming the FPGA 2.11. Initializing the IP Core
2.2. Licensing IP Cores x
2.2.1. OpenCore Plus IP Evaluation
2.7. Integrating Your IP Core in Your Design x
2.7.1. Pin Assignments 2.7.2. External Transceiver Reconfiguration Controller Required in Stratix V Designs 2.7.3. Transceiver PLL Required in Arria 10 Designs 2.7.4. External Time-of-Day Module for Variations with 1588 PTP Feature 2.7.5. Clock Requirements for 40GBASE-KR4 Variations 2.7.6. External TX MAC PLL 2.7.7. Placement Settings for the Low Latency 40-100GbE IP Core
2.8. Low Latency 40-100GbE IP Core Testbenches x
2.8.1. Low Latency 40-100GbE IP Core Testbench Overview 2.8.2. Understanding the Testbench Behavior
2.9. Simulating the Low Latency 40‑100GbE IP Core With the Testbenches x
2.9.1. Generating the Low Latency 40-100GbE Testbench 2.9.2. Optimizing the Low Latency 40‑100GbE IP Core Simulation With the Testbenches 2.9.3. Simulating with the Modelsim Simulator 2.9.4. Simulating with the NCSim Simulator 2.9.5. Simulating with the VCS Simulator 2.9.6. Testbench Output Example: Low Latency 40-100GbE IP Core
3. Functional Description x
3.1. High Level System Overview 3.2. Low Latency 40-100GbE MAC and PHY Functional Description 3.3. Signals 3.4. Software Interface: Registers 3.5. Ethernet Glossary
3.2. Low Latency 40-100GbE MAC and PHY Functional Description x
3.2.1. Low Latency 40-100GbE IP Core TX Datapath 3.2.2. Low Latency 40-100GbE IP Core TX Data Bus Interfaces 3.2.3. Low Latency 40-100GbE IP Core RX Datapath 3.2.4. Low Latency 40-100GbE IP Core RX Data Bus Interface 3.2.5. Low Latency 100GbE CAUI–4 PHY 3.2.6. External Reconfiguration Controller 3.2.7. External Transceiver PLL 3.2.8. External TX MAC PLL 3.2.9. Congestion and Flow Control Using Pause Frames 3.2.10. Pause Control and Generation Interface 3.2.11. Pause Control Frame Filtering 3.2.12. Link Fault Signaling Interface 3.2.13. Statistics Counters Interface 3.2.14. 1588 Precision Time Protocol Interfaces 3.2.15. PHY Status Interface 3.2.16. Transceiver PHY Serial Data Interface 3.2.17. Low Latency 40GBASE-KR4 IP Core Variations 3.2.18. Control and Status Interface 3.2.19. Arria 10 Transceiver Reconfiguration Interface 3.2.20. Clocks 3.2.21. Resets
3.2.1. Low Latency 40-100GbE IP Core TX Datapath x
3.2.1.1. Preamble, Start, and SFD Insertion 3.2.1.2. Address Insertion 3.2.1.3. Length/Type Field Processing 3.2.1.4. Frame Padding 3.2.1.5. Frame Check Sequence (CRC-32) Insertion 3.2.1.6. Inter‑Packet Gap Generation and Insertion 3.2.1.7. Error Insertion Test and Debug Feature
3.2.2. Low Latency 40-100GbE IP Core TX Data Bus Interfaces x
3.2.2.1. Low Latency 40-100GbE IP Core User Interface Data Bus 3.2.2.2. Low Latency 40-100GbE IP Core TX Data Bus with Adapters (Avalon-ST Interface) 3.2.2.3. Low Latency 40-100GbE IP Core TX Data Bus Without Adapters (Custom Streaming Interface) 3.2.2.4. Bus Quantization Effects With Adapters 3.2.2.5. User Interface to Ethernet Transmission
3.2.2.5. User Interface to Ethernet Transmission x
3.2.2.5.1. Order of Transmission
3.2.3. Low Latency 40-100GbE IP Core RX Datapath x
3.2.3.1. Low Latency 40-100GbE IP Core RX Filtering 3.2.3.2. 40-100GbE IP Core Preamble Processing 3.2.3.3. 40-100GbE IP Core FCS (CRC-32) Removal 3.2.3.4. 40-100GbE IP Core CRC Checking 3.2.3.5. LL 40-100GbE IP Core Malformed Packet Handling 3.2.3.6. RX CRC Forwarding 3.2.3.7. Inter-Packet Gap 3.2.3.8. Pause Ignore 3.2.3.9. Control Frame Identification
3.2.4. Low Latency 40-100GbE IP Core RX Data Bus Interface x
3.2.4.1. Low Latency 40-100GbE IP Core User Interface Data Bus 3.2.4.2. Low Latency 40-100GbE IP Core RX Data Bus 3.2.4.3. Low Latency 40-100GbE IP Core RX Data Bus Without Adapters (Custom Streaming Interface)
3.2.9. Congestion and Flow Control Using Pause Frames x
3.2.9.1. Conditions Triggering XOFF Frame Transmission 3.2.9.2. Conditions Triggering XON Frame Transmission
3.2.13. Statistics Counters Interface x
3.2.13.1. OctetOK Count Interface
3.2.14. 1588 Precision Time Protocol Interfaces x
3.2.14.1. Implementing a 1588 System That Includes a LL 40-100GbE IP Core 3.2.14.2. PTP Receive Functionality 3.2.14.3. PTP Transmit Functionality 3.2.14.4. External Time-of-Day Module for 1588 PTP Variations 3.2.14.5. PTP Timestamp and TOD Formats 3.2.14.6. 1588 PTP Interface Signals
3.3. Signals x
3.3.1. Low Latency 40-100GbE IP Core Signals
3.4. Software Interface: Registers x
3.4.1. Low Latency 40-100GbE IP Core Registers 3.4.2. LL 40‑100GbE Hardware Design Example Registers
3.4.1. Low Latency 40-100GbE IP Core Registers x
3.4.1.1. PHY Registers 3.4.1.2. Link Fault Signaling Registers 3.4.1.3. LL 40GBASE-KR4 Registers 3.4.1.4. Low Latency 40-100GbE IP Core MAC Configuration Registers 3.4.1.5. Pause Registers 3.4.1.6. TX Statistics Registers 3.4.1.7. RX Statistics Registers 3.4.1.8. 1588 PTP Registers
3.4.2. LL 40‑100GbE Hardware Design Example Registers x
3.4.2.1. Packet Client Registers
4. Debugging the Link x
4.1. Creating a SignalTap II Debug File to Match Your Design Hierarchy
A. Arria 10 10GBASE-KR Registers x
A.1. 10GBASE-KR PHY Register Definitions
C. Additional Information x
C.1. Low Latency 40- and 100-Gbps Ethernet MAC and PHY MegaCore Function User Guide Archives C.2. Low Latency 40- and 100-Gbps Ethernet MAC and PHY MegaCore Function User Guide Revision History C.3. How to Contact Altera C.4. Typographic Conventions
1. About the Low Latency 40- and 100-Gbps Ethernet MAC and PHY IP Core
2. Getting Started
3. Functional Description
4. Debugging the Link
A. Arria 10 10GBASE-KR Registers
B. Differences Between Low Latency 40-100GbE IP Core and 40-100GbE IP Core v15.1
C. Additional Information

3.2.14.3. PTP Transmit Functionality

When you send a 1588 PTP packet to a Low Latency 40-100GbE IP core with Enable 1588 PTP turned on in the parameter editor, you must assert one and only one of the following input signals with the TX SOP signal to tell the IP core the incoming packet is a 1588 PTP packet:

  • tx_egress_timestamp_request_valid: assert this signal to tell the IP core to process the current packet in two-step processing mode.
  • tx_etstamp_ins_ctrl_timestamp_insert: assert this signal to tell the IP core to process the current packet in one-step processing mode and to insert the exit timestamp for the packet in the packet (insertion mode).
  • tx_etstamp_ins_ctrl_residence_time_update: assert this signal to tell the IP core to process the current packet in one-step processing mode and to update the timestamp in the packet by adding the latency through the IP core (the residence time in the IP core) to the cumulative delay field maintained in the packet (correction mode). This mode supports transparent clock systems.

The IP core transmits the 1588 PTP packet in an Ethernet frame after PTP processing.

Figure 34. PTP Transmit Block Diagram

In one-step mode, the IP core either overwrites the timestamp information provided at the user-specified offset with the packet exit timestamp (insertion mode), or adds the residence time in this system to the value at the specified offset (correction mode). You tell the IP core how to process the timestamp by asserting the appropriate signal with the TX SOP signal. You must specify the offset of the timestamp in the packet (tx_etstamp_ins_ctrl_offset_timestamp) in insertion mode, or the offset of the correction field in the packet (tx_etstamp_ins_ctrl_offset_correction_field) in correction mode. In addition, the IP core zeroes out or updates the UDP checksum, or leaves the UDP checksum as is, depending on the mutually exclusive tx_etstamp_ins_ctrl_checksum_zero and tx_etstamp_ins_ctrl_checksum_correct signals.

Two-step PTP processing ignores the values on the one-step processing signals. In two-step processing mode, the IP core does not modify the current timestamp in the packet. Instead, the IP core transmits a two-step derived timestamp on the separate tx_egress_timestamp_96b_data[95:0] or tx_egress_timestamp_64b_data[63:0] bus, when it begins transmitting the Ethernet frame. The value on the tx_egress_timestamp_{96b,64b}_data bus is the packet exit timestamp. The tx_egress_timestamp_{96b,64b}_data bus holds a valid value when the corresponding tx_egress_timestamp_{96b,64b}_valid signal is asserted.

In addition, to help the client to identify the packet, you can specify a fingerprint to be passed by the IP core in the same clock cycle with the timestamp. To specify the number of distinct fingerprint values the IP core can handle, set the Timestamp fingerprint width parameter to the desired number of bits W. You provide the fingerprint value to the IP core in the tx_egress_timestamp_request_fingerprint[(W–1):0] signal. The IP core then drives the fingerprint on the appropriate tx_egress_timestamp_{96b,64b}_fingerprint[(W–1):0] port with the corresponding output timestamp, when it asserts the tx_egress_timestamp_{96b,64b}_valid signal.

The IP core calculates the packet exit timestamp.

exit TOD = entry TOD + IP core maintained expected latency + user-specified extra latency

  • entry TOD is the value in tx_time_of_day_96b_data or tx_time_of_day_64b_data when the packet enters the IP core.
  • The expected latency through the IP core is a static value. The IP core maintains this value internally.
  • The IP core reads the user-specified extra latency from the TX_PTP_EXTRA_LATENCY register. This option is provided for user flexibility.

The IP core provides the exit TOD differently in different processing modes.

  • In two-step mode, the IP core drives the exit TOD on tx_egress_timestamp_96b_data and on tx_egress_timestamp_64b_data, as available.
  • In one-step processing insertion mode, the IP core inserts the exit TOD in the timestamp field of the packet at the offset you specify in tx_etstamp_ins_ctrl_offset_timestamp.
  • In one-step processing correction mode, the IP core calculates the exit TOD and uses it only to calculate the residence time.

In one-step processing correction mode, the IP core calculates the updated correction field value:

exit correction field value = entry correction field value + residence time + asymmetry extra latency

  • residence time = exit TOD – entry (ingress) timestamp.
  • entry (ingress) timestamp is the value on tx_etstamp_ins_ctrl_ingress_timestamp_{95,64}b in the SOP cycle when the IP core received the packet on the TX client interface. The application is responsible to drive this signal with the correct value for the cumulative calculation. The correct value depends on system configuration.
  • The IP core reads the asymmetry extra latency from the TX_PTP_ASYM_DELAY register if the tx_egress_asymmetry_update signal is asserted. This option is provided for additional user-defined precision. You can set the value of this register and set the tx_egress_asymmetry_update signal to indicate the register value should be included in the latency calculation.
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