Ethernet Design Example Components User Guide

ID 683044
Date 11/21/2023
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

1.4. Using the TOD Clock

Follow these guidelines when using the TOD clock:

  • 96-bit timestamp format—load the time-of-day using the time_of_day_96b_load_data[] bus or the SecondsH, SecondsL, and NanoSec registers. The bus value always takes precedence over the register values. When loading the time-of-day through the time_of_day_96b_load_data[] bus, the output is available in the time_of_day_96[] bus after one clock cycle. Hence, Intel® recommends that you add one clock cycle to the value of the time_of_day_96b_load_data[] bus to accommodate the latency.
  • 64-bit timestamp format—load the time-of-day using the time_of_day_64b_load_data[] bus. The output is available in the time_of_day_64[] bus after one clock cycle. Hence, Intel® recommends that you add one clock cycle to the value of the incoming time-of-day to accommodate the latency.
  • The TOD clock does not synchronize the 96-bit and 64-bit timestamp format.
  • The drift, jitter, and wander timers restart each time a new time-of-day is loaded, either through the signal or configuration registers.