SLLSEC6E September 2012 – June 2019 DP83848-EP
PRODUCTION DATA.
When Auto-Negotiation is enabled, the DP83848-EP transmits the abilities programmed into the Auto-Negotiation Advertisement register (ANAR) at address 04h via FLP Bursts. Any combination of 10 Mbps, 100 Mbps, Half-Duplex, and Full Duplex modes may be selected.
Auto-Negotiation Priority Resolution:
The Basic Mode Control Register (BMCR) at address 00h provides control for enabling, disabling, and restarting the Auto-Negotiation process. When Auto-Negotiation is disabled, the Speed Selection bit in the BMCR controls switching between 10-Mbps or 100-Mbps operation, and the Duplex Mode bit controls switching between full duplex operation and half duplex operation. The Speed Selection and Duplex Mode bits have no effect on the mode of operation when the Auto-Negotiation Enable bit is set.
The Link Speed can be examined through the PHY Status Register (PHYSTS) at address 10h after a Link is achieved.
The Basic Mode Status Register (BMSR) indicates the set of available abilities for technology types, Auto-Negotiation ability, and Extended Register Capability. These bits are permanently set to indicate the full functionality of the DP83848-EP (only the 100BASE-T4 bit is not set because the DP83848-EP does not support that function).
The BMSR also provides status on:
The Auto-Negotiation Advertisement Register (ANAR) indicates the Auto-Negotiation abilities to be advertised by the DP83848-EP. All available abilities are transmitted by default, but any ability can be suppressed by writing to the ANAR. Updating the ANAR to suppress an ability is one way for a management agent to change (restrict) the technology that is used.
The Auto-Negotiation Link Partner Ability Register (ANLPAR) at address 0x05h is used to receive the base link code word as well as all next page code words during the negotiation. Furthermore, the ANLPAR will be updated to either 0081h or 0021h for parallel detection to either 100 Mbps or 10 Mbps, respectively.
The Auto-Negotiation Expansion Register (ANER) indicates additional Auto-Negotiation status. The ANER provides status on: