DP83849IF_15 Datasheet, PDF (32/105 Pages) Texas Instruments – DP83849IF PHYTER DUAL Industrial Temperature with Fiber Support (FX) and Flexible Port Switching Dual Port 10/100 Mb/s Ethernet Physical Layer Tranceiver

DP83849IF
SNOSAX8D – JUNE 2009 – REVISED APRIL 2013
AN_EN
0
0
0
0
AN_EN
1
1
1
1
Table 5-1. Auto-Negotiation Modes
AN1
0
0
1
1
AN1
0
0
1
1
AN0
0
1
0
1
AN0
0
1
0
1
Forced Mode
10BASE-T, Half-Duplex
10BASE-T, Full-Duplex
100BASE-TX, Half-Duplex
100BASE-TX, Full-Duplex
Advertised Mode
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
10BASE-T Half-Duplex
100BASE-TX, Half-Duplex
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
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5.2.2 Auto-Negotiation Register Control
When Auto-Negotiation is enabled, the DP83849IF 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 DP83849IF (only the 100BASE-T4 bit is not set since the DP83849IF 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 DP83849IF. 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.
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Configuration
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