Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.1.6.9.7. Receive Path Functions

The EMAC can be programmed to capture the timestamp of all packets received on the GMII interface or to process packets to identify the valid PTP messages. You can control the snapshot of the time to be sent to the application by using the following options of the MAC_Timestamp_Control register:
  • Enable snapshot for all packets
  • Enable snapshot for IEEE 1588 version 2 timestamp
  • Enable snapshot for PTP packets transmitted directly over Ethernet
  • Enable timestamp snapshot for the received packet for IPv4 or IPv6
  • Enable timestamp snapshot only for EVENT messages (SYNC, DELAY_REQ, PDELAY_REQ, or PDELAY_RESP)
  • Enable the node to be a time transmitter or time receiver and select the snapshot type
Note:
  • EMAC also supports the PTP messages over VLAN packets.
  • When the packet size is less than 64 Bytes on the RX side, EMAC does not generate timestamp for such packets, and passes it to the application.