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.
OR
- 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).