GTS Ethernet Hard IP User Guide: Agilex™ 3 FPGAs and SoCs

ID 848477
Date 7/07/2025
Public
Document Table of Contents

12.4.3. Make PTP UI Adjustments

This section provides steps to measure UI value to prevent time drift due to clock PPM differences as referenced to golden Time-of-Day (TOD) in the platform.
Tip: The TOD value increments constantly based on the golden TOD running at the ideal clock with 0 PPM difference. If you observe a large adjustment to the TOD value, don't perform measurement or discard any performed measurement as it impacts the measurement result.

TAM is the reference time for Alignment Marker (AM) for variants with AM, and an arbitrary selected reference bit for variants without AM.

For simulation or hardware run with 0 PPM setting, you can skip the measurement and program 0 PPM UI value as defined in the table.
Table 64.  Default or 0 PPM UI Value
Attention: The UI value provided in this table is different from the UI value at serial line in the UI Value and PMA Delay section.
Mode 0 PPM UI value (ps) 0 PPM UI value

{4-bit ns, 28-bit fractional ns}

10GE-1 96.9697 32’h018D3019