AM79C971VCW datasheet(247/265 Pages) AMD

247 / 265 page

APPENDIX E

Am79C971

E-1

Auto-Negotiation Registers

The following registers exist in the Auto-Negotiation

block and are written or read by using registers MII Ad-

dress (BCR33) and MII Data Port (BCR34). These reg-

isters are indirect read and write registers with the

0) portion of the MII Address Register (BCR33). The

PHYAD (BCR33, bits 3-0) portion specifies the specific

PHY that you wish to communicate with. The internal

PHY on the Am79c971 controller has a PHYAD ad-

dress of 1fh. The default external PHY has a PHYAD

address of 00h. The following is a table of these indirect

registers and defaulted values for the internal registers.

Bit

Name

Default

Description

PRPHY

Reset.

Defaults

ZERO

after power-up and

after hardware resets

(H_RESET). This is

normally only used to

bring up the external

PHY into a known

state. Not used for the

internal PHY. Use the

normal

Am79C971

reset mechanisms.

NA (0)

Loop Back. Defaults

to ZERO after power-

up and after hardware

resets

(H_RESET).

Loopback

supported only in an

external

PHY.

See

the

“MII

Configuration”

section

for

details..

NA (0)

Speed

Selection.

Defaults

ZERO

after power-up and

after hardware resets

(H_RESET). This is

ZERO the entire time

the internal PHY is

active. The external

PHY can be forced

into

100Mbps

10Mbps

mode

manipulation of this

bit. This bit is used

only when the Auto-

Negotiation

Enable

bit is ZERO.

ANE

Variable*

Auto-Negotiation

Enable. Defaults to

ONE after power-up

and after hardware

resets

(H_RESET).

This bit enables the

internal or

external

PHY’s

Auto-

Negotiation

capabilities.

When

this bit is ZERO the

internal/external

PHY’s must be forced

into the correct state

through

software

intervention.

NA (0)

Power

Down.

Defaults

ZERO

after power-up and

after hardware resets

(H_RESET). This bit

only applies to the

external

PHY.

Use

the SLEEP# or other

power saving modes

the

Am79C971

Controller.

* See text on Auto Negotiation.

AM79C971VCW Datasheet(PDF) 247 Page - Advanced Micro Devices

AM79C971VCW Datasheet(HTML) 247 Page - Advanced Micro Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Descarga

Enlace URL