22.214.171.124. PTP Receive Functionality
If you turn on Enable IEEE 1588 PTP in the E-Tile Hard IP for Ethernet Intel FPGA IP parameter editor, the IP core provides a 96-bit (V2 format) with every packet on the RX client interface, whether it is a 1588 PTP packet or not. The value on the timestamp bus o_ptp_rx_its is valid in the same clock cycle as the RX SOP signal. The value on the timestamp bus is not the current timestamp; instead, it is the timestamp from the time when the IP core received the packet on the Ethernet link. The IP core captures the time-of-day from the TOD module on i_ptp_tod at the time it receives the packet on the Ethernet link, and sends that timestamp to the client on the RX SOP cycle on the timestamp bus o_ptp_rx_its. User software/hardware logic can use this timestamp or ignore it based on whether it is a 1588 PTP packet or not.
The RX PTP operation assumes the o_sl_rx_ptp_ready signal was asserted and is held high.