LAN9211 datasheet(25/147 Pages) SMSC

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

Datasheet

SMSC LAN9211

Revision 2.9 (03-01-12)

DATASHEET

3.5

Wake-up Frame Detection

Setting the Wake-Up Frame Enable bit (WUEN) in the “WUCSR—Wake-up Control and Status

reception is disabled, and detection logic within the MAC examines receive data for the pre-

programmed wake-up frame patterns. The LAN9211 can be programmed to notify the host of the wake-

up frame detection with the assertion of the host interrupt (IRQ) or assertion of the power management

event signal (PME). Upon detection, the Wake-Up Frame Received bit (WUFR) in the WUCSR is set.

When the host clears the WUEN bit the LAN9211 will resume normal receive operation.

Before putting the MAC into the wake-up frame detection state, the host must provide the detection

logic with a list of sample frames and their corresponding byte masks. This information is written into

the Wake-up Frame Filter register (WUFF). Please refer to Section 5.4.11, "WUFF—Wake-up Frame

Filter," on page 114 for additional information on this register.

The MAC supports four programmable filters that support many different receive packet patterns. If

remote wake-up mode is enabled, the remote wake-up function receives all frames addressed to the

MAC. It then checks each frame against the enabled filter and recognizes the frame as a remote wake-

up frame if it passes the wakeup frame filter register’s address filtering and CRC value match.

In order to determine which bytes of the frames should be checked by the CRC module, the MAC uses

a programmable byte mask and a programmable pattern offset for each of the four supported filters.

The pattern’s offset defines the location of the first byte that should be checked in the frame. Since

the destination address is checked by the address filtering Function, the pattern offset is always greater

than 12.

The byte mask is a 31-bit field that specifies whether or not each of the 31 contiguous bytes within

the frame, beginning in the pattern offset, should be checked. If bit j in the byte mask is set, the

detection logic checks byte offset +j in the frame. In order to load the Wake-up Frame Filter register,

the host LAN driver software must perform eight writes to the Wake-up Frame Filter register (WUFF).

The Diagram shown in Table 3.2, "Wake-Up Frame Filter Register Structure" below, shows the wake-

up frame filter register’s structure.

Note 3.1

Wake-up frame detection can be performed when the LAN9211 is in the D0 or D1 power

states. In the D0 state, wake-up frame detection is enabled when the WUEN bit is set.

Note 3.2

Wake-up frame detection, as well as Magic Packet detection, is always enabled and

cannot be disabled when the device enters the D1 state.

Note 3.3

When wake-up frame detection is enabled via the WUEN bit of the WUCSR—Wake-up

Control and Status Register, a broadcast wake-up frame will wake-up the device despite

the state of the Disable Broadcast Frame (BCAST) bit in the MAC_CR—MAC Control

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