LAN89218 datasheet(20/148 Pages) MICROCHIP

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LAN89218

DS60001255B-page 20

 2008-2015 Microchip Technology Inc.

3.3

Address Filtering Functional Description

The Ethernet address fields of an Ethernet Packet, consists of two 6-byte fields: one for the destination address and

one for the source address. The first bit of the destination address signifies whether it is a physical address or a

multicast address.

The LAN89218 address check logic filters the frame based on the Ethernet receive filter mode that has been enabled.

Filter modes are specified based on the state of the control bits in Table 3-1, which shows the various filtering modes

used by the Ethernet MAC Function. These bits are defined in more detail in the MAC_CR—MAC Control Register.

If the frame fails the filter, the Ethernet MAC function does not receive the packet. The host has the option of

accepting or ignoring the packet.

TABLE 3-1:

ADDRESS FILTERING MODES

MCPAS

PRMS

INVFILT

HPFILT

Description

MAC address perfect filtering only

for all addresses.

MAC address perfect filtering for

physical address and hash filtering

for multicast addresses

Hash Filtering for physical and multi-

cast addresses

Inverse Filtering

Promiscuous

Pass all multicast frames. Frames

with physical addresses are perfect-

filtered

Pass all multicast frames. Frames

with physical addresses are hash-fil-

tered

LAN89218 Datasheet(PDF) 20 Page - Microchip Technology