AR8327-AL1A-R datasheet(54/394 Pages) ETC2

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54 • AR8327/AR8327N Seven-port Gigabit Ethernet Switch

Atheros Communications, Inc.

54 • June 2011

COMPANY CONFIDENTIAL

2.20.1

IEEE 802.3az LPI Mode

AR8327 works in the following modes when 802.3 az feature is turned on:

n Active: the regular mode to transfer data

n Sleep: send special signal to inform remote link of entry into low-power state

n Quiet: No signal transmitted on media, most of the analog and digital blocks are turned off to

reduce energy.

n Refresh: send periodically special training signal to maintain timing recovery and equalizer

coefficients

n Wake: send special wake-up signal to remote link to inform of the entry back into Active.

The AR8327 supports both 100Base-Tx EEE and 1000Base-T EEE.

100Base-Tx EEE allows asymmetrical operation, which allows each link partner to enter the LPI mode

independent of the other partner.

1000Base-T EEE requires symmetrical operation, which means that both link partners must enter the

LPI mode simultaneously.

Figure 2-3 shows the 802.3az operating states for the AR8031.

Figure 2-4 shows the 802.3az operating power modes — 802.3az for the AR8327.

Figure 2-5.

Operating States — 802.3az LPI Mode

Figure 2-6.

Operating Power Modes — 802.3az LPI Mode

Active

Q uiet

Quiet

Low -Pow er

Existing state used for data transm ission .

Data packets or IPG /Idle sym bols are

transm itted

N ew state used during periods of no data

transm ission to allow system pow er

reduction between data packet bursts

O perating States

Active

Quiet

Low-Power

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