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Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface
Datasheet
SMSC LAN9420/LAN9420i 59 Revision 1.22 (09-25-08)
DATASHEET
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.
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”.
3.5.4.1 Magic 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.
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 Wakeup Generation Cases
FILTER
ENABLED
(Note 3.2)
CRC
MATCH
(Note 3.3)
GLOBAL
UNICAST
ENABLED
(Note 3.4)
PASS
REGULAR
RECEIVE
FILTER
ADDRESS
TYPE
(Note 3.5)
BROAD-
CAST
FRAME
MULTI-
CAST
FRAME
UNICAST
FRAME
Yes Yes x x x Yes No No
Yes Yes Yes x x No No Yes
Yes Yes x Yes Multicast
(=1)
No Yes No
Yes Yes x Yes Unicast
(=0)
No No Yes