Link Status - 16.2 English

1G/2.5G Ethernet PCS/PMA or SGMII LogiCORE IP Product Guide (PG047)

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16.2 English

When High, the link is valid and has remained valid after this register was last read; synchronization of the link has been obtained and Auto-Negotiation (if enabled) has completed and the reset sequence of the transceiver (if present) has completed.

When Low, either:

  • A valid link has not been established: link synchronization has failed or Auto-Negotiation (if enabled) has failed to complete.


  • Link synchronization was lost at some point after this register was previously read. However, the current link status might be good. Therefore, read this register a second time to get confirmation of the current link status.

Regardless of whether Auto-Negotiation is enabled or disabled, there can be some delay to the deassertion of Link Status following the loss of synchronization of a previously successful link. This is due to the Auto-Negotiation state machine which requires that synchronization is lost for an entire link timer duration before changing state. For more information, see the 802.3 specification (the an_sync_status variable).