Determine whether Auto-Negotiation has completed successfully by doing one of the following.
• Poll the Auto-Negotiation completion bit 1.5 in MDIO register 1: Status register.
• Use the Auto-Negotiation interrupt port of the core.
If Auto-Negotiation is not completing:
1. Ensure that Auto-Negotiation is enabled in both the core and in the link partner (the device or test equipment connected to the core). Auto-Negotiation cannot complete successfully unless both devices are configured to perform Auto-Negotiation.
The Auto-Negotiation procedure requires that the Auto-Negotiation handshaking protocol between the core and its link partner, which lasts for several link timer periods, occur without a bit error. A detected bit error causes Auto-Negotiation to go back to the beginning and restart. Therefore, a link with an exceptionally high bit error rate might not be capable of completing Auto-Negotiation, or might lead to a long Auto-Negotiation period caused by the numerous Auto-Negotiation restarts. If this appears to be the case, try the next step and see Problems with a High Bit Error Rate .
2. Try disabling Auto-Negotiation in both the core and the link partner and see if both devices report a valid link and are able to pass traffic. If they do, it proves that the core and link partner are otherwise configured correctly. If they do not pass traffic, see Problems in Obtaining a Link (Auto-Negotiation Disabled) ).