Motorola MPC823e Reference Manual page 786

Communication Processor Module
• SET GROUP ADDRESS—This command is used to set a bit in one of the 64 bits of the
four individual/group address hash filter registers. The individual or group address to be
added to the hash table must be written to TADDR_L, TADDR_M, and TADDR_H in the
parameter RAM before executing this command. The RISC microcontroller checks the
I/G bit in the address stored in TADDR to determine whether to use the individual hash
table or the group hash table. A zero in the I/G bit implies an individual address and a
1 in the I/G bit implies a group address. This command can be executed at any time,
regardless of whether the Ethernet channel is enabled.
If you need to delete an address from the hash table, disable the Ethernet channel,
clear the hash table registers, and execute this command for the remaining addresses.
You must do this because the hash table might have mapped multiple addresses to the
same hash table bit.
16.9.22.10 SCCx ETHERNET ADDRESS RECOGNITION. The SCCx Ethernet controller
can filter the received frames based on different addressing types—physical (individual),
group (multicast), broadcast (all-ones group address), and promiscuous. You can set the
promiscuous address type in the PSMR–SCC Ethernet register. The difference between an
individual address and a group address is determined by the I/G bit in the destination
address field, which is part of the standard Ethernet protocol. A flowchart for address
recognition on received frames is illustrated in Figure 16-108.
In the physical type of address recognition, the SCCx Ethernet controller compares the
destination address field of the received frame with the physical address that you program
in PADDR1_H, PADDR1_M, and PADDR1_L. You can also perform address recognition on
multiple individual addresses using the IADDR1–4 hash table.
16-332 MPC823e REFERENCE MANUAL MOTOROLA