pnx1500 NXP Semiconductors, pnx1500 Datasheet - Page 735

• Manufacturer Part Number: pnx1500
• Description: Pnx15xx Series Connected Media Processor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Volume 1 of 1
PNX15XX_SER_3
Product data sheet
5.12.6 Enabling and Disabling Filtering
5.12.7 Runt Frames
5.13.1 Overview
5.13 Wake-up on LAN
RxFilterWOLEn is also enabled, a wake up event will cause an interrupt to the
system, and the RxFilterWOL in the RxFilterStatus register will be also be set. All the
status bits in RxFilterStatus must be cleared by software after the system is powered
up. However when the system is powered up and is receiving packets normally, the
corresponding PatternMatch bit in the RxFilterStatus register for each one of the four
pattern-match filters is put in status display mode for the incoming packet. They are
read-only, and there is no need to clear them. When multiple pattern matches are
joined, their PatternMatch bits are all set together based on the outcome of the joined
pattern match.
The pattern-matching filters described in the previous sections can be bypassed by
setting the PassRxFilter bit in the Command register. When the PassRxFilter bit is
set, all receive packets will be passed to memory. In this case the device driver
software must implement all filtering functionality in software.
Setting the PassRxFilter bit does not affect the runt frame filtering as defined in the
next section.
A packet with less than 64 bytes (or 68 bytes for VLAN frames) is shorter than the
minimum Ethernet frame size, and therefore is considered erroneous. For example,
they might be collision fragments. The Receive Datapath automatically filters and
discards runt frames without writing them to memory and without using a receive
descriptor.
When a runt frame has a correct CRC, there is a possibility that it is intended to be
useful. The device driver can receive runt frames with correct CRC by setting the
PassRuntFrame bit of the Command register to 1.
The Ethernet module supports power management with remote wake-up over a local
area network. The host system of the Ethernet module can be powered down, even
including part of the LAN100 Ethernet module itself, while the Ethernet module
continues to listen to packets on the LAN. Packets that are appropriately formed can
be received and recognized by the Ethernet module, and can be used to trigger the
host system to wake up from its power-down state.
System wake-up takes effect through an interrupt. When a wake-up event is detected,
the WakeupInt bit in the IntStatus register is set. The interrupt status will trigger an
interrupt if the corresponding WakeupIntEn bit in the IntEnable register is set.
While in a power-down state, the packet that generates a Wake-up-on-LAN event is
lost.
There are two ways in which Ethernet packets can trigger wake-up events: generic
Wake-up on LAN and Magic Packet. The generic Wake-up-on-LAN functionality is
based on the filtering as defined in
Rev. 3 — 17 March 2006
Chapter 23: LAN100 — Ethernet Media Access Controller
Section
5.12; magic packet filtering uses an
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
PNX15xx Series
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