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3.0 Configuration (Continued)

3.4 Auto-Negotiation Register Set

The strapping option settings of Auto-Negotiation, speed,

and duplex capabilities that initialized during power-up or at

reset can be altered any time by writing to the BMCR 0x00,

ANAR 0x04 or, to 1KTCR 0x09.

When Auto-Negotiation is enabled, the DP83865 transmits

the abilities programmed in the ANAR 0x04, and 1KTCR

0x09 via FLP Bursts. The following combinations of

10 Mbps,100 Mbps, 1000 Mbps, Half Duplex, and Full

Duplex modes may be selected.

The Auto-Negotiation protocol compares the contents of

the ANLPAR (received from link partner) and ANAR regis-

ters (for 10/100 Mbps operation) and the contents of

1000BASE-T status and control registers, and uses the

results to automatically configure to the highest perfor-

mance protocol (i.e., the highest common denominator)

between the local and the link partner. The results of Auto-

Negotiation may be accessed in registers BMCR 0x00

(Duplex Status and Speed Status), and BMSR 0x01 (Auto-

Neg Complete, Remote Fault, Link).

The BMCR 0x00 provides control for enabling, disabling,

and restarting the Auto-Negotiation process.

The BMSR 0x01 indicates the set of available abilities for

technology types, Auto-Negotiation ability, and extended

cate the full functionality of the DP83865. The BMSR also

provides status on:

— Auto-Negotiation is completed on bit 5

— The Link Partner is advertising that a remote fault has

occurred on bit 4

— A valid link has been established on bit 2

The ANAR 0x04 stores the capabilities advertised during

Auto-Negotiation. All available capabilities are transmitted

by default. However, the advertised capability can be sup-

pressed by writing to the ANAR. This is a commonly used

by a management agent to change (i.e., to force) the com-

munication technology.

The ANLPAR 0x05 is used to store the received base link

code word as well as all next page code words during the

negotiation that is transmitted from the link partner.

If Next Page is NOT being used, then the ANLPAR will

store the base link code word (link partner's abilities) and

retain this information from the time the page is received,

indicated by a ‘1’ in bit 1 of the ANER 0x06, through the

end of the negotiation and beyond.

During the next page exchange operation, the station man-

ager can not wait till the end of Auto-Negotiation to read

the ANLPAR because the register is used to store both the

base and next pages. The next page content overwrites the

base page content. The station manager needs to closely

monitor the negotiation status and to perform the following

tasks.

— ANER 0x06 bit 1 is ‘1’ indicates a page is received. Sta-

tion manage reads the base page information from

ANLPAR0x05 and stores the content in the memory.

— After reading the base page information, software needs

to write to ANNPTR 0x07 to load the next page informa-

tion to be sent.

— The operation can be implemented as polled or interrupt

driven. If another page is received by polling bit 1 in the

ANER 0x06 or by interrupt, the station manager reads bit

15 of the ANLPAR indicating the partner has more next

pages to send. If the partner has more pages to send,

ANNPTR needs to be written to load another next page.

The ANER 0x06 indicates additional Auto-Negotiation sta-

tus. The ANER provides status on:

— A Parallel Detect Fault has occurred (bit 4, ANER 0x06).

— The Link Partner supports the Next Page function (bit 3,

ANER 0x06).

— The DP83865 supports the Next Page function (bit 2,

ANER 0x06).

— The current page being exchanged by Auto-Negotiation

has been received (bit1, ANER 0x06).

— The Link Partner supports Auto-Negotiation (bit 0, ANER

0x06).

The ANNPTR 0x07 contains the next page code word to be

transmitted. See also Section “2.3 Register Description”

for details.

3.5 Auto-MDIX resolution

The GigPHYTER V can determine if a “straight” or “cross-

over” cable is used to connect to the link partner. It can

automatically re-assign channel A and B to establish link

with the link partner, (and channel C and D in 1000BASE-T

mode). Auto-MDIX resolution precedes the actual Auto-

Negotiation process that involves exchange of FLPs to

advertise capabilities. Automatic MDI/MDIX is described in

IEEE 802.3ab Clause 40, section 40.8.2. It is not a required

implementation for 10BASE-T and 100BASE-TX.

Table 38. Advertised Modes during Auto-Negotiation,

AN_EN = 1

SPEED1

SPEED0

DUPLEX

Adertised Modes

1000BASE-T HD, 10BASE-T HD

1000BASE-T HD

1000BASE-T HD, 100BASE-TX HD

1000BASE-T HD, 100BASE-TX HD,

10BASE-T HD

1000BASE-T FD, 10BASE-T FD

1000BASE-T FD

1000BASE-T FD, 100BASE-TX FD

1000BASE-T FD, 100BASE-TX FD,

10BASE-T FD

Table 39. PMA signal to MDI and MDIX pin-out

Contact

MDI

MDIX

MDI_A+

MDI_B+

MDI_A-

MDI_B-

MDI_B+

MDI_A+

MDI_C+

MDI_D+

MDI_C-

MDI_D-

MDI_B-

MDI_A-

MDI_D+

MDI_C+

MDI_D-

MDI_C-

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