F-Tile Ethernet Intel® FPGA Hard IP User Guide

ID 683023
Date 3/28/2022
Public

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4.4.2. PTP Timestamp Accuracy

The IP core supports two timestamps accuracy modes, Basic and Advanced. In advanced mode, additional logic generates the high accuracy PTP timestamps.

PTP Timestamp Accuracy in Basic Mode

When you select Basic in the Timestamp accuracy mode under PTP tab in the parameter editor for F-Tile Ethernet Intel® FPGA Hard IP core, TX and RX data paths of multiple Ethernet IP instances share a single TOD clock output.
  • The time-of-day (TOD) module can be shared across multiple IP instances of different data rates
  • The F-Tile Ethernet Intel® FPGA Hard IP instance 1 and instance 2, shown below, can be located on different F-tiles
  • Any 390.625 MHz frequency clock source can drive the TOD clock
Figure 12. TOD Clock and TOD Connections in Basic Accuracy ModeThe figure displays recommended TOD clock connection. The TOD clock source should be 390.625 MHz.

PTP Timestamp Accuracy in Advanced Mode

When you select Advanced in the Timestamp accuracy mode under PTP tab in the parameter editor, the IP core requires a single Master TOD module and dedicated TOD Synchronizer and TOD modules for both, TX and RX PTP instances.

Figure 13. TOD Clock and TOD Connections in Advanced Accuracy ModeThe figure displays recommended TOD clock connection.
Table 12.  PTP Timestamp Accuracy per Ethernet Data Rate Measured in Simulation
Important: The timestamp accuracy values in Basic and Advanced modes reflect simulation results only. Hardware accuracy values may differ and will be available in the future release.
Ethernet Data Rate PTP Timestamp Accuracy
Basic Mode Advanced Mode
10GE ± 3ns ± 1.5ns
25GE ± 3ns ± 1.5ns
50GE ± 8ns ± 1.5ns
100GE ± 8ns ± 1.5ns
200GE ± 8ns ± 8ns
400GE ± 8ns ± 8ns