82551QM Datasheet, PDF (37/120 Pages) Intel Corporation – Fast Ethernet Multifunction PCI/CardBus Controller

Networking Silicon — 82551QM
5.3.2.2
5.4
5.5
This allows the 82551QM to handle various packet types. In general, the 82551QM supports
programmable filtering of any packet in the first 128 bytes.
When the 82551QM is in one of the low power states, it searches for a predefined pattern in the
first 128 bytes of the incoming packets. The only exception is the Magic Packet, which is scanned
for the entire frame. The 82551QM classifies the incoming packets into one of the following
categories:
• No Match. The 82551QM discards the packet and continues to process the incoming packets.
• TCO Packet. The 82551QM implements perfect filtering of TCO packets. After a TCO
packet is processed, the 82551QM is ready for the next incoming packet. There are two
possible system environments:
— TCO controller on the SMB. The entire TCO packet is transferred to the TCO controller.
— System without TCO controller. TCO packets are treated as any other wake-up packets
and may assert the PME# signal if configured to do so.
• Wake-up Packet. The 82551QM is capable of recognizing and storing the first 128 bytes of a
wake-up packet. If a wake-up packet is larger than 128 bytes, its tail is discarded by the
82551QM. After the system is fully powered-up, software has the ability to determine the
cause of the wake-up event through the PMDR and dump the stored data to the host memory.
Magic Packets are an exception. The Magic Packets may cause a power management event
and set an indication bit in the PMDR; however, it is not stored by the 82551QM for use by the
system when it wakes up.
Link Status Change Event
The 82551QM link status indication circuit is capable of issuing a PME on a link status change
from a valid link to an invalid link condition or vice versa. The 82551QM reports a PME link status
event in all power states. The PME# signal is gated by the PME Enable bit in the PMCSR and the
CSMA Configure command.
CardBus Power Management
The CardBus Power Management Proposal differs from the PCI Power Management Specification
in the following manner:
• The PME# signal is replaced by CSTSCHG which is an active high output signal.
• An auxiliary power source, V_AUX, is supplied on the same V_cc pins.
• An auxiliary power source bit in the PMC register must be set.
• The PCI clock signal and the PCI reset signal are guaranteed to be kept low in the B3 state.
In addition, the 82551QM also meets the CardBus requirement for current consumption less than
70 mA in the D0u state.
Wake on LAN (Preboot Wake-up)
When the 82551QM is drawing power from an auxiliary power source (V_AUX), it can support the
same preboot Wake on LAN (WOL) capabilities as the 82559 device. The 82551QM enters WOL
mode after the following events occur:
Datasheet
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