- Core set to the 1000BASE-X standard. The auto-negotiation state machine operates as described in 1000BASE-X Standard.
- Core set to perform the SGMII standard. The auto-negotiation state machine operates as described in SGMII Standard.
- Standard is switched during an auto-negotiation sequence. The auto-negotiation state machine does not immediately switch standards, but attempt to continue to completion at the original standard.
- Switching the standard using MDIO. This does not cause auto-negotiation to automatically restart. AMD recommends that after switching to a new standard using an MDIO write, immediately perform the following:
- If you have switched to the 1000BASE-X standard, reprogram the Auto-Negotiation Advertisement register (Register 4) to the desired settings.
- For either standard, restart the Auto-Negotiation sequence by writing to bit 0.9 of the MDIO Control register (Register 0).