TNETE2101

10BASE-T/100BASE-TX/100BASE-FX

LOW-POWER PHYSICAL-LAYER INTERFACE

SPWS032D – JANUARY 1997 – REVISED MARCH 1999

22

POST OFFICE BOX 655303

autonegotiation advertisement register – an_adv at 0x04

BIT

15

14

13

12

11

10

987654321

BIT

0

NP

ACK

RF

Technology Ability Field

Selector Field

Figure 11. Autonegotiation Advertisement Register

Table 8. Autonegotiation Advertisement Register Bit Functions

BIT

FUNCTION

NAME

NO.

FUNCTION

NP

15

Autonegotiation next page. When NP is set to 1, the autonegotiation process indicates to the link partner that the

PHY wishes to exchange next pages. The capability of the link partner to exchange next pages can be determined

by the value of the LPNPABLE bit in the AN_exp register. When the link partner is capable of next-page exchange,

it requests an exchange by setting the LPNP bit to 1 in the AN_lpa register. Then, the autonegotiation process waits

until the next page is written to the AN_np register, and the link partner has had its next page loaded. The link partner’s

next page then is received into the AN_lpa register.

A consequence of this process is that the PHY fails to complete autonegotiation if the PHY and its link partner agree

to exchange next pages, but the link partner never sends its next page. A software timeout, which forces

renegotiation with NP cleared to 0, should be implemented to avoid this situation.

The default value of NP is 0.

ACK

14

Acknowledge. Reserved for internal use of the autonegotiation process. Write as 0, ignore during read.

RF

13

Remote fault. When RF is set to 1, the PHY indicates a remote fault condition to its link partner. The type of fault,

as well as the criteria and method of fault detection, is PHY specific. The default value of RF is 0.

12,11

Autonegotiation advertised technology ability. Bits 12–5 represent an 8-bit value sent to the link partner to indicate

the abilities of the PHY. Once negotiated, the values of the bits are reflected in bits 12–5 in register 0

×05 of the link

partner.

Bits 11 and 12 are set to 0 by default. These bits are reserved for future use according to IEEE 802.3u. These bits

can be changed and are sent to the link partner during autonegotiation.

Technology

Ability

Field

10

Pause operation of full duplex links. Defined for use at the MAC level and when set to a 1 signifies that the MAC is

capable of performing the pause function. The pause capability is exchanged between the PHYs during the

autonegotiation but does not change the PHY’s mode of operation. The pause function is valid only during full-duplex

operation regardless of the medium. The default value of this bit is 0.

9

100BASE-T4. Default value is a 0 and should not be set to a 1 since the TNETE2101 does not support this medium.

8

100BASE-TX full duplex. Set to 1 to advertise availability to the link partner.

7

100BASE-TX half duplex. Set to 1 to advertise availability to the link partner.

6

10BASE-T full duplex. Set to 1 to advertise availability to the link partner.

5

10BASE-T half duplex. Set to 1 to advertise availability to the link partner.

Selector Field

4–0

Autonegotiation selector field code. This field has a default value of 0001, meaning that the PHY supports only IEEE

Std 802.3 format link code words.