User manual

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
Tr ue
Tr ue
Multiple IND
?
Broadcast
Address
Use Indicated
Tabl e
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
Tr ue
Tr ue
False
False True
Tr ue
FalseFalse
?
Broadcast
Enabled
?
Tr ue Fa lse
False
Multiple Individual
Addresses
Single
Address