Highly Efficient Single-Chip 10/100 Non-PCI Ethernet Controller
Datasheet
Table 3.5 Filter i Offset Bit Definitions
FILTER I OFFSET DESCRIPTION
FIELD
DESCRIPTION
7:0
Pattern Offset: The offset of the first byte in the frame on which CRC is checked for wake-up frame
recognition. The minimum value of this field must be 12 since there should be no CRC check for
the destination address and the source address fields. The MAC checks the first offset byte of the
frame for CRC and checks to determine whether the frame is a wake-up frame. Offset 0 is the first
byte of the incoming frame's destination address.
The Filter i CRC-16 register contains the CRC-16 result of the frame that should pass Filter i.
Table 3.6 describes the Filter i CRC-16 bit fields.
Table 3.6 Filter i CRC-16 Bit Definitions
FILTER I CRC-16 DESCRIPTION
FIELD
DESCRIPTION
15:0
Pattern CRC-16: This field contains the 16-bit CRC value from the pattern and the byte mask
programmed to the wake-up 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.
3.5.1
Magic Packet Detection
Setting the Magic Packet Enable bit (MPEN) in the “WUCSR—Wake-up Control and Status Register”,
places the LAN9116 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
LAN9116 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 managment event signal (PME). Upon detection, the
Magic Packet Received bit (MPR) in the WUCSR is set. When the host clears the MPEN bit the
LAN9116 will resume normal receive operation. Please refer to Section 5.4.12, "WUCSR—Wake-up
Control and Status Register," on page 101 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.
Revision 1.1 (05-17-05)
SMSC LAN9116
DATA2S8HEET
SMSC [ SMSC CORPORATION ]
