
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 23: LAN100 — Ethernet Media Access Controller
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
23-67
additional lter for magic packet detection. In both cases, a WoL event is only
triggered if the triggering packet has a valid CRC.
Figure 13 illustrates the wake-up
functionality.
The following subsections describe the two WoL mechanisms.
The
RxFilterWoLStatus register can be read by the software to inspect the reason
for a Wake-up event. Before going into a power-down condition, the power
management software should clear the register by writing the RxFilterWolClear
register.
5.13.2
Filtering for WoL
The receive lter functionality as described in
Section 5.12 can be used to generate
WoL events. If the RxFilterEnWoL bit of the RxFilterCtrl register is set, the receive
lter will set the WakeupInt bit of the IntStatus register if a packet is received that
passes the lter. The interrupt will only be generated if the CRC of the packet is
correct.
In case a wake-up is generated by the receive lter, the RxFilterWoL bit in the
RxFilterWoLStatus register will be set along with the origin of the lter match, which
will be set in the AcceptPerfectWoL, AcceptMulticastHashWoL,
AcceptUnicastHashWoL, AcceptMulticastWoL, AcceptBroadcastWoL,
AcceptUnicastWoL bits of the same register. Software can reset these bits by writing
a 1 to the corresponding bits of the RxFilterWoLClear register.
5.13.3
Magic Packet WoL
The LAN100 supports wake-up using AMD's Magic Packet technology (see “Magic
Packet technology”, Advanced Micro Devices). A Magic Packet is a specially formed
packet solely intended for wake-up purposes. This packet can be received, analyzed
and recognized by the Ethernet module and used to trigger a wake-up event.
A packet is a Magic Packet if it contains the station address repeated 16 times in its
data portion with no breaks or interruptions, preceded by six synchronization bytes
with the value 0xFF. Other data may surround the Magic Packet pattern in the data
portion of the packet. The whole packet must be a well-formed Ethernet frame.
The magic packet detection unit analyzes the Ethernet packets, extracts the packet
address and checks the payload for the Magic Packet pattern. The address from the
packet is used for matching the pattern (not the address in the SA0/1/2 registers). A
magic packet only sets the wake-up interrupt status bit if the packet passes the
receive lter, as illustrated in gure
Figure 13: the result of the receive lter is ANDed
with the magic packet lter result to produce the nal result.
Magic Packet ltering is enabled by setting the MagicPacketEnWoL bit of the
RxFilterCtrl register. Note that when doing Magic Packet WoL, the RxFilterEnWoL bit
in the RxFilterCtrl register should be 0. Setting the RxFilterEnWoL bit to 1 would
accept all packets for a matching address, not just the Magic Packets, that is, WoL
using Magic Packets is more strict.