Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface

Datasheet

Table 3.18 Filter i CRC-16 Bit Definitions

FILTER i CRC-16 DESCRIPTION

BITS DESCRIPTION

15:0 Pattern CRC-16:This field contains the 16-bit CRC value from the pattern and the byte mask programmed to the wakeup filter register function. This value is compared against the CRC calculated on the incoming frame, and a match indicates the reception of a wakeup frame.

Table 3.19 indicates the cases that produce a wake when the Wakeup Frame Enable (WAKE_EN) bit of the Wakeup Control and Status Register (WUCSR) is set. All other cases do not generate a wake.

Table 3.19 Wakeup Generation Cases

 

 

GLOBAL

PASS

 

 

 

 

FILTER

CRC

UNICAST

REGULAR

ADDRESS

BROAD-

MULTI-

 

ENABLED

MATCH

ENABLED

RECEIVE

TYPE

CAST

CAST

UNICAST

(Note 3.2)

(Note 3.3)

(Note 3.4)

FILTER

(Note 3.5)

FRAME

FRAME

FRAME

 

 

 

 

 

 

 

 

Yes

Yes

x

x

x

Yes

No

No

 

 

 

 

 

 

 

 

Yes

Yes

Yes

x

x

No

No

Yes

 

 

 

 

 

 

 

 

Yes

Yes

x

Yes

Multicast

No

Yes

No

 

 

 

 

(=1)

 

 

 

 

 

 

 

 

 

 

 

Yes

Yes

x

Yes

Unicast

No

No

Yes

 

 

 

 

(=0)

 

 

 

 

 

 

 

 

 

 

 

Note 3.2 As determined by bit 0 of Filter i Command.

Note 3.3 CRC matches Filter i CRC-16 field.

Note 3.4 As determined by bit 9 of WUCSR.

Note 3.5 As determined by bit 2 of Filter i Command.

Note: x indicates “don’t care”.

3.5.4.1Magic Packet Detection

Setting the Magic Packet Enable bit (MPEN) in the Section 4.4.12, "Wakeup Control and Status Register (WUCSR)," on page 133, places the 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 MAC can be programmed to assert the wake event interrupt to the Interrupt Controller on detection. Upon detection, the Magic Packet Received bit (MPR) in the WUCSR is set. When the Host clears the MPEN bit, normal receive operation will resume. Please refer to Section 4.4.12, "Wakeup Control and Status Register (WUCSR)," on page 133 for additional information on this register

In Magic Packet mode, logic within the MAC 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 MAC checks each received frame for the pattern 48’hFF_FF_FF_FF_FF_FF after the destination and source address field.

SMSC LAN9420/LAN9420i

59

Revision 1.22 (09-25-08)

 

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