Freescale Semiconductor MPC8260 - Manual (Page 795)

SCC Ethernet Mode
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 25-11
25.10 SCC Ethernet Address Recognition
The Ethernet controller can filter received frames based on different addressing types—physical
(individual), group (multicast), broadcast (all-ones group address), and promiscuous. The difference
between an individual address and a group address is determined by the I/G bit in the destination address
field. A flowchart for address recognition on received frames is shown in
Figure 25-4 .
In the physical type of address recognition, the Ethernet controller compares the destination address field
of the received frame with the user-programmed physical address in PADDR1. Address recognition can
be performed on multiple individual addresses using the IADDR1–4 hash table.
Figure 25-4. Ethernet Address Recognition Flowchart
In group address recognition, the controller determines whether the group address is a broadcast address.
If broadcast addresses are enabled, the frame is accepted, but if the group address is not a broadcast
Check Address
I/G Address
?
Hash_Search
False
G
True
True
Multiple IND
?
Broadcast
Address
Use Indicated
Table
Hash Search
Use Group
Table
Match
?
Match
?
Receive Frame
Ignore REJECT
Receive Frame
Ignore REJECT
Match
?
Receive Frame
Ignore REJECT
PROMISC
?
Start Receive
Discard Frame if REJECT
Discard Frame
is Asserted
I
True
True
False
False True
True
False False
?
Broadcast
Enabled
?
True False
False
Multiple Individual
Addresses
Single
Address