AM79C978VCSLASHW datasheet(81/261 Pages) AMD

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Am79C978

Header AID Remote Control Word Commands

Stations may be configured either as master stations or

as slave stations. Only one master may exist on a given

HomePNA segment.

The master station may send commands embedded in

the HomePNA header control word to remotely set var-

ious parameters of the remote slave stations. Stations

are identified via the AID as follows:

1. The master station is identified on the HomePNA

wire network with an AID of FFh.

2. A slave is identified with an AID of 00h to EFh.

3. AID values of F0h to FEh are reserved for future

use.

Once a command has been transmitted, the master

station will revert to a slave AID, so that subsequent

control words are not interpreted as new commands.

Master mode is entered by writing to the PHY control

the command sequence.

A valid master remote command consists of three

HomePNA frames with an AID of FFh. Since the

HomePNA header is prepended to packets received

from the MAC as well as Any1Home packets. Packets

from the master station may be separated by intervals

during which other (slave) stations may transmit their

frames.

A remote master Control Word command must be rec-

ognized and executed by a HomePNA PHY when it re-

ceives three consecutive valid HomePNA frames with

an AID of FFh.

If HPR16, bit 15 is not set to 0, valid commands are as

follows:

1. SET_POWER: Commands slave stations to set

their transmit level to a prescribed level.

2. SET_SPEED: Commands slave stations to set their

transmit speed to a prescribed value.

The control word bit encoding and possible values are

described in Table 14.

Table 14.

Master Station Control Word Functions

All stations will transmit the following status messages

in the HomePNA header control word of all outgoing

frames:

1. VERSION_STATUS: The HomePNA PHY version

of the slave station.

2. POWER_STATUS: The transmit power level of the

transmitting slave station for the current frame. All

HomePNA units support LOW_POWER and

HIGH_POWER modes.

3. SPEED_STATUS: The transmit speed of the slave

station for the current frame. Receiving stations will

adjust their receiver parameters to correctly inter-

pret this frame.

The slave control word bit encoding and possible val-

ues are also described in Table 14.

PHY Control and Management Block (PCM

Block)

The management interface specified in Clause 22 of

the IEEE 802.3u standard provides for a simple two

wire, serial interface to connect a management entity

and a managed PHY for the purpose of controlling the

PHY and gathering status information. The two lines

are Management Data Input/Output (MDIO) and Man-

agement Data Clock (MDC). A station management

entity which is attached to multiple PHY entities must

have prior knowledge of the appropriate PHY address

for each PHY entity.

Description of the Methodology

The management interface physically transports man-

agement information across the internal and external

MII. The information is encapsulated in a frame format

as specified in Clause 22 of the IEEE 802.3u draft stan-

dard and is shown in Table 15.

Table 15.

MII Control Frame Format

Aid No.

LSB

MSB

Version

Set to:

0 = Low Power

1 = High Power

Set to:

0 = Low Speed

1 = High Speed

Reserved

PRE

PHYAD

REGAD

DATA

IDLE

READ

1.1

AAAAA

RRRRR

D31………D0

WRITE

1.1

AAAAA

RRRRR

D31………D0

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