WG82577LM S LGWS Intel, WG82577LM S LGWS Datasheet - Page 47

• Manufacturer Part Number: WG82577LM S LGWS
• Manufacturer: Intel

Specifications of WG82577LM S LGWS

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Device Functionality—82577 GbE PHY
7.4.1.3.1.4
Magic Packet
Magic packets are defined as follows:
The 82577 expects the destination address to either:
If the packet destination address met one of the three criteria previously listed, the
82577 searches for 16 repetitions of the same destination address in the packet's data
field. Those 16 repetitions must be preceded by (in the data field) at least 6 bytes of
0xFF, which act as a synchronization stream. If the destination address is NOT the
broadcast address (FF.FF.FF.FF.FF.FF), the 82577 assumes that the first non-0xFF byte
following at least 6 0xFF bytes is the first byte of the possible matching destination
address. If the 96 bytes following the last 0xFF are 16 repetitions of the destination
address, the 82577 accepts the packet as a valid wake up Magic Packet. Note that this
definition precludes the first byte of the destination address from being 0xFF.
A Magic Packet’s destination address must match the address filtering enabled in the
configuration registers with the exception that broadcast packets are considered to
match even if the Broadcast Accept bit (bit 5) of the RCTL register is 0b. If APM wake
up is enabled in the NVM, the 82577 starts up with the RAH0/RAL0 register 0 loaded
from the NVM. This enables the 82577 to accept packets with the matching IEEE
address before the software device driver comes up.
Offset
0
6
12
12
12
Any
any+6
1. Be the broadcast address (FF.FF.FF.FF.FF.FF)
2. Match the value in Receive Address (RAH0/RAL0) register 0. This is initially loaded
3. Match any other address filtering enabled by the software device driver.
from the NVM but can be changed by the software device driver.
— Magic Packet Technology Details - Once the 82577 has been put into Magic
# of Bytes
6
6
4
8
4
6
96
Packet mode, it scans all incoming frames addressed to the node for a specific
data sequence, which indicates to the MAC that this is a Magic Packet frame. A
Magic Packet frame must also meet the basic requirements for the LAN
technology chosen, such as Source address, Destination Address (which might
be the receiving station’s IEEE address or a Multicast address that includes the
Broadcast address) and CRC. The specific data sequence consists of 16
duplications of the IEEE address of this node with no breaks or interruptions.
This sequence can be located anywhere within the packet, but must be
preceded by a synchronization stream. The synchronization stream enables the
scanning state machine to be much simpler. The synchronization stream is
defined as 6 bytes of 0xFF. The device also accepts a Broadcast frame, as long
as the 16 duplications of the IEEE address match the address of the system
that needs to wake up.
Field
Destination Address
Source Address
Possible VLAN Tag
Possible Len/LLC/SNAP
Header
Type
Synchronizing Stream
16 copies of Node Address
Value
FF*6+
A*16
Action
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Comment
MAC Header – processed by main
address filter
Compared to RAH0/RAL0 register
40