Datasheet

DP83640
www.ti.com SNOSAY8E –SEPTEMBER 2007–REVISED APRIL 2013
Table 5-1. Auto-Negotiation Modes
AN_EN AN1 AN0 Forced Mode
0 0 0 10BASE-T, Half-Duplex
0 0 1 10BASE-T, Full-Duplex
0 1 0 100BASE-TX, Half-Duplex
0 1 1 100BASE-TX, Full-Duplex
AN_EN AN1 AN0 Advertised Mode
1 0 0 10BASE-T, Half/Full-Duplex
1 0 1 100BASE-TX, Half/Full-Duplex
1 1 0 100BASE-TX Full-Duplex
1 1 1 10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
5.2.2 Auto-Negotiation Register Control
When Auto-Negotiation is enabled, the DP83640 transmits the abilities programmed into the Auto-
Negotiation Advertisement register (ANAR) at address 04h via FLP Bursts. Any combination of 10 Mb/s,
100 Mb/s, Half-Duplex, and Full Duplex modes may be selected.
Auto-Negotiation Priority Resolution:
1. 100BASE-TX Full Duplex (Highest Priority)
2. 100BASE-TX Half Duplex
3. 10BASE-T Full Duplex
4. 10BASE-T Half Duplex (Lowest Priority)
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 Mb/s or 100 Mb/s 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 DP83640 (only the 100BASE-T4 bit is not set since the DP83640 does not support that
function).
The BMSR also provides status on:
• Whether or not Auto-Negotiation is complete
• Whether or not the Link Partner is advertising that a remote fault has occurred
• Whether or not valid link has been established
• Support for Management Frame Preamble suppression
The Auto-Negotiation Advertisement Register (ANAR) indicates the Auto-Negotiation abilities to be
advertised by the DP83640. 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 05h 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 Mb/s or 10 Mb/s respectively.
The Auto-Negotiation Expansion Register (ANER) indicates additional Auto-Negotiation status. The ANER
provides status on:
Copyright © 2007–2013, Texas Instruments Incorporated Configuration 41
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