IEEE1722 Real Time Clock Format | Xilinx UG492 instruction

IEEE1722 Real Time Clock Format

Because the Xilinx Tri-Mode Ethernet MACs have a known fixed latency, the time stamps taken can easily be translated into the equivalent GMII position to comply with the standard. This is performed in the software drivers where the MAC transmitter and receiver latencies are held in #defines in a header file. The software drivers also contain placeholder #defines for users to input the PHY-specific latency values for the PHYs used in the system.

IEEE1722 Real Time Clock Format

The IEEE1722 specification defines the avbtp_timestamp field. This is derived by sampling the IEEE802.1 AS Real Time Clock and converting the low order time to nanoseconds. From version 2.1 onwards, this conversion is now performed in the Ethernet AVB Endpoint core and an alternative RTC, in the 1722 format, is output on the rtc_nanosec_field_1722[31:0] port.

This port contains a 32-bit word representing nanosecond values. Unlike the IEEE802.1 AS nanosecond field (which resets back to zero when it reaches 1 second), the IEEE1722 nanosecond field counts fully to 0xFFFFFFFF before wrapping around. The field therefore wraps around approximately every 4 seconds.

If the system is using the IEEE1722 functionality, this port can be sampled to create the avbtp_timestamp field. Otherwise this port can be ignored.

Ethernet AVB Endpoint User Guide

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UG492 July 23, 2010

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Xilinx UG492 manual IEEE1722 Real Time Clock Format

Contents

UG492 July 23 LogiCORETM IP Ethernet AVB Endpoint Date Version Revision Revision History Table of Contents Generating the Core Precise Timing Protocol Packet Buffers Quick Start Example Design Detailed Example Design EDK format Ethernet AVB Endpoint User Guide 1Example AVB Home Network Schedule of Figures Constraining the Core System Integration Figure A-1RTC Periodic Error Ethernet AVB Endpoint User Guide Schedule of Tables 17Tri-Mode Ethernet MAC and Ethernet Statistics Detailed Example Design EDK format Ethernet AVB Endpoint User Guide About This Guide Guide Contents Typographical Conventions Online Document ConventionsConvention Meaning or Use Example Acronym Spelled Out List of Abbreviations Vhdl Conventions Acronym Spelled Out Preface About This Guide System Requirements IntroductionAbout the Core Windows Additional Core Resources Recommended Design ExperienceTechnical Support Feedback Feedback Document Introduction Before you Begin License Options Licensing the CoreSimulation Only Full System Hardware Evaluation Obtaining Your License Key Installing the License File 1Example AVB Home Network Overview of Ethernet Audio Video Bridging AVB Specifications P802.1ASOverview of Ethernet Audio Video Bridging P802.1Qav AVB SpecificationsTalker Assumptions Listener Assumptions P802.1Qat Typical Implementation Typical Implementation UG492 July 23 Ethernet AVB GUI Generating the Core Component Name Core Delivery FormatGenerating the Core Number of PLB Masters PLB Base AddressEthernet AVB GUI Output Generation Parameter Values in the XCO File Core Architecture Core Architecture Standard Core Generator Format EDK pcore Format EDK pcore Format PLB Interface Functional Block DescriptionAV Traffic Interface Legacy Traffic Interface Rx Splitter Tx ArbiterMAC Header Filters Functional Block Description Tx PTP Packet Buffers Precise Timing Protocol BlocksTx Time Stamp Rx PTP Packet Buffers RTC Tri-Mode Ethernet MACs Software Drivers 1Clocks and Resets Signal Direction Description Clocks and ResetCore Interfaces Core Interfaces Legacy Traffic Transmitter Path Signals Legacy Traffic Receiver Path Signals3Legacy Traffic Signals Receiver Path Direction Description AV Traffic Transmitter Path Signals 3Legacy Traffic Signals Receiver Path4AV Traffic Signals Transmitter Path Direction Description 5AV Traffic Signals Receiver Path Direction Description AV Traffic Receiver Path SignalsTri-Mode Ethernet MAC Client Interface MAC Transmitter Interface MAC Management Interface MAC Receiver Interface Processor Local Bus PLB Interface PIN Name Direction Description PLB Interface Ethernet AVB Endpoint User Guide 10Interrupt Signals Direction Description Interrupt Signals Signal Direction Description PTP Signals Tx Legacy Traffic I/F Ethernet AVB Endpoint Transmission Ethernet AVB Endpoint Transmission Error Free Legacy Frame Transmission Errored Legacy Frame Transmission Tx AV Traffic I/FTx AV Traffic I/F 3Normal Frame Transmission across the AV Traffic Interface Overview Tx ArbiterCredit Based Traffic Shaping Algorithm Tx Arbiter 4Credit-based Shaper Operation Tx Arbiter Bandwidth Control IdleSlopeSendSlope LoLimit HiLimit Ethernet AVB Endpoint Reception Rx SplitterRx Legacy Traffic I/F Ethernet AVB Endpoint Reception Error Free Legacy Frame Reception Legacy MAC Header Filters Errored Legacy Frame ReceptionOverview of Operation Rx Legacy Traffic I/F 3Normal Frame Reception Address Filter Match MAC Header Filter Configuration Full Destination Address DA Match Single MAC Header Filter Usage Examples 5Filtering of Frames with a Partial DA Match Partial Destination Address DA Match Any Other Combinations Vlan Priority Match Error Free AV Traffic Reception Rx AV Traffic I/FRx AV Traffic I/F 8Errored Frame Reception across the AV Traffic Interface Errored AV Traffic Reception Real Time Clock Real Time Clock and Time Stamping Real Time Clock and Time Stamping RTC Implementation Increment of Nanoseconds FieldReal Time Clock Increment of the Seconds Field Controlled Frequency RTCSynchronized RTC Time Stamping Logic Time Stamping Logic 3Time Stamping Position Time Stamp Sampling Position of MAC Frames IEEE1722 Real Time Clock Format IEEE1722 Real Time Clock Format Real Time Clock and Time Stamping Tx PTP Packet Buffer Precise Timing Protocol Packet Buffers 1Tx PTP Packet Buffer Structure Precise Timing Protocol Packet Buffers Rx PTP Packet Buffer Rx PTP Packet Buffer 2Rx PTP Packet Buffer Configuration and Status Processor Local Bus InterfaceSingle Read Transaction 1Single Read Transaction Configuration and Status Processor Local Bus Interface Single Write Transaction PLB Address Map and Register Definitions Ethernet AVB Endpoint Address Space PLB Address Map and Register Definitions Ethernet AVB Endpoint Address Space Ethernet Audio Video End Point Configuration RegistersRx PTP Packet Buffer Address Space Tx PTP Packet Buffer Address Space Rx Filtering Control Register Rx PTP Packet Control Register Tx Arbiter Send Slope Control Register Tx Arbiter Idle Slope Control RegisterRTC Offset Control Registers Current RTC Value Registers RTC Increment Value Control Register RTC Interrupt Clear Register Phase Adjustment Register Software Reset Register PTP Receiver logic reset. When written with a Address Default Access Description 16MAC Header Filter Configuration Registers Cont’d MAC Configuration and Statistics Tri-Mode Ethernet MAC Address SpaceMAC Address Filter Registers MAC Mdio Registers 102 Required Constraints Constraining the Core PLBclk Period Constraints for Clock NetsHostclk Txclk Timespecs for Critical Logic within the Core RtcclkRequired Constraints Inst Ethernet AVB Endpoint User Guide 107 108 Ethernet AVB Endpoint User Guide 109 110 System Integration Using the Xilinx LogiCORE IP Tri-Mode Ethernet MACs LogiCORE IP Tri-Mode Ethernet MAC Soft Core Tri-Mode Ethernet MAC Core GenerationSystem Integration Connections Without Ethernet Statistics Using the Xilinx LogiCORE IP Tri-Mode Ethernet MACs 114 GND Connections Including Ethernet Statistics LogiCORE IP Embedded Tri-Mode Ethernet MACs Ethernet AVB Endpoint User Guide 117 118 Virtex-6 Fpga Embedded Tri-Mode Ethernet MAC 120 PLB Using an EDK Project Top Level PLB Using an ISE Software Top-Level Project Ethernet AVB Endpoint User Guide 123 Using the Xilinx XPS LocalLink Tri-Mode Ethernet MAC Xpslltemac configurationIntroduction System Overview AVB capable xpslltemac Using the Xilinx XPS LocalLink Tri-Mode Ethernet MAC Ethernet AVB Endpoint Connections 9Connection to the XPS LocalLink Tri-Mode Ethernet MAC MHS File Syntax END Ethernet AVB Endpoint User Guide 129 130 Clock Master Software Drivers Software System Integration Clock SlaveDriver Instantiation Software Drivers Software System Integration Interrupt Service Routine Connections When Using a LogiCORE IP Tri-Mode Ethernet MAC Ethernet AVB Endpoint SetupCore Initialization System-Specific Defines in xavbhw.h Setting up GrandMaster Discontinuity Callback Handler Setting up SourcePortIdentity and Default TX PTP Messages Starting and Stopping the AVB Drivers Overview Quick Start Example Design 1Ethernet AVB Endpoint Example Design and Test Bench Quick Start Example Design Generating the Core 2Ethernet AVB Endpoint Core Customization Screen Implementing the Example Design Setting up for Simulation Functional SimulationSimulating the Example Design Implementing the Example Design Timing Simulation What’s Next? Project directory Detailed Example Design Standard Format Directory and File Contents Project directory/component name Component name/docComponent name/example design 5Implement Directory Name Description Component name/implement Component name/simulation Implement/resultsSimulation/functional 6Results Directory Name Description Name Description Simulation/timing Drivers/avbv204a/data Componentname/drivers/v204aDrivers/avbv204a/examples 11Driver Example Directory Name Description Drivers/avbv204a/src Implementation Scripts Simulation ScriptsImplementation Scripts Example Design HDL for the Ethernet AVB Endpoint Example Design Top-Level Example Design HDL Ethernet Frame StimulusExample Design Loopback Module Ethernet Frame Checker PLB Module 2Ethernet AVB Endpoint Demonstration Test Bench Demonstration Test Bench Customizing the Test Bench Simulation Run TimeChanging Frame Data Viewing the Simulation Wave Form 3Simulator Wave Window Contents Detailed Example Design EDK format Detailed Example Design EDK format Component name/MyProcessorIPLib MyProcessorIPLib/pcores/ethavbendpointv204aPcores/ethavbendpointv204a/data Pcores/ethavbendpointv204a/netlist Pcores/ethavbendpointv204a/hdl/vhdlMyProcessorIPLib/drivers/avbv204a 5Driver Data Directory Name Description 8Driver Example Directory Name Description 164 Ethernet AVB Endpoint User Guide 165 166 RTC Real Time Instantaneous Error RTC Time Stamp AccuracyTime Stamp Accuracy Appendix a RTC Time Stamp Accuracy Figure A-1RTC Periodic Error Time Stamp Accuracy RTC Sampling Error Figure A-3Sampling Position Uncertainty Figure A-4Overall Time Stamp Accuracy Accuracy Resulting from the Combined Errors 172