Low Latency 40-Gbps Ethernet IP Core User Guide

ID 683745
Date 3/08/2021
Document Table of Contents

3.2.13. 1588 Precision Time Protocol Interfaces

If you turn on Enable 1588 PTP , the LL 40GbE core processes and provides 1588 Precision Time Protocol (PTP) timestamp information as defined in the IEEE 1588-2008 Precision Clock Synchronization Protocol for Networked Measurement and Control Systems Standard. This feature supports PHY operating speed with a timestamp accuracy of ± 7 ns .

1588 PTP packets carry timestamp information. The LL 40GbE core updates the incoming timestamp information in a 1588 PTP packet to transmit a correct updated timestamp with the data it transmits on the Ethernet link, using a one-step or two-step clock.

A fingerprint can accompany a 1588 PTP packet. You can use this information for client identification and other client uses. If provided fingerprint information, the IP core passes it through unchanged.

The IP core connects to a time-of-day (TOD) module that continuously provides the current time of day based on the input clock frequency. Because the module is outside the LL 40GbE core, you can use the same module to provide the current time of day for multiple modules in your system.