Timestamp Sampling Position of MAC Frames - 9.0 English

Tri-Mode Ethernet MAC LogiCORE IP Product Guide (PG051)

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9.0 English

A timestamp value should be sampled at the beginning of the first symbol following the Start of Frame Delimiter (SFD) of the Ethernet MAC frame.

Figure 1. Timestamping Position

The previous figure illustrates the timestamp sampling position that is used by the core. Timestamps are taken after the MAC frame SFD is seen on the GMII.

  • If the PHY specific latency values are available the software drivers can use them to adjust the timestamps and improve overall system accuracy.