Communication Processor Module
16-324
MPC823 USER’S MANUAL
MOTOROLA
SCC2
COMMUNICATION
16
PROCESSOR
MODULE
CLOSE RX BD—This command should not be used when the SCC2 is in Ethernet
mode.
INIT RX PARAMETERS—This command initializes all the receive parameters in this
serial channel parameter RAM to their reset state and should only be issued when the
reset the receive and transmit parameters.
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 should 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 SCC2 ETHERNET ADDRESS RECOGNITION. The SCC2 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–SCC2 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
In the physical type of address recognition, the SCC2 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.