LAN9211 datasheet(28/146 Pages) SMSC

28 / 146 page

High-Performance Small Form Factor Single-Chip Ethernet Controller with HP Auto-MDIX

Datasheet

Revision 1.93 (11-27-07)

SMSC

LAN9211

DATASHEET

3.5.1

Magic Packet Detection

Setting the Magic Packet Enable bit (MPEN) in the “WUCSR—Wake-up Control and Status Register”,

places the LAN9211 MAC in the “Magic Packet” detection mode. In this mode, normal data reception

is disabled, and detection logic within the MAC examines receive data for a Magic Packet. The

LAN9211 can be programmed to notify the host of the “Magic Packet” detection with the assertion of

the host interrupt (IRQ) or assertion of the power management event signal (PME). Upon detection,

the Magic Packet Received bit (MPR) in the WUCSR is set. When the host clears the MPEN bit the

LAN9211 will resume normal receive operation. Please refer to Section 5.4.12, "WUCSR—Wake-up

Control and Status Register," on page 116 for additional information on this register

In Magic Packet mode, the Power Management Logic constantly monitors each frame addressed to

the node for a specific Magic Packet pattern. It checks only packets with the MAC’s address or a

broadcast address to meet the Magic Packet requirement. The Power Management Logic checks each

received frame for the pattern 48h FF_FF_FF_FF_FF_FF after the destination and source address

field.

Then the Function looks in the frame for 16 repetitions of the MAC address without any breaks or

interruptions. In case of a break in the 16 address repetitions, the PMT Function scans for the

48'hFF_FF_FF_FF_FF_FF pattern again in the incoming frame.

The 16 repetitions may be anywhere in the frame but must be preceded by the synchronization stream.

The device will also accept a multicast frame, as long as it detects the 16 duplications of the MAC

address. If the MAC address of a node is 00h 11h 22h 33h 44h 55h, then the MAC scans for the

following data sequence in an Ethernet: Frame.

Destination Address Source Address ……………FF FF FF FF FF FF

00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55

…CRC

It should be noted that Magic Packet detection can be performed when LAN9211 is in the D0 or D1

power states. In the D0 state, “Magic Packet” detection is enabled when the MPEN bit is set. In the

D1 state, Magic Packet detection, as well as wake-up frame detection, are automatically enabled when

the device enters the D1 state.

3.6

Checksum Offload Engines (COE)

The LAN9211 contains two checksum offload engines, which offload the calculation of the 16-bit

checksum for transmitted and received Ethernet frames. The functionality of the checksum offload

engines is described in the following sections:

Receive Checksum Offload Engine (RXCOE)

Transmit Checksum Offload Engine (TXCOE)

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