Software Model
MU9C8338A 10/100Mb Ethernet Filter Interface
Port Configure Extended Register
The register also allows the user to enable a Permanent bit
check that is performed during SA processing. When bit 3
is set to 0 (default), the SA processing function will use
the command in the SSAU register when it finds a
matching LANCAM entry. This typically updates the
LANCAM entry by writing to it through a Mask register.
In the case when the entry was added as a Permanent
entry, the Port ID may be over-written during this
operation. If the user wants Permanent entries to be
untouched during SA learns; bit 3 should be set 1. This
will cause the SA Learn built-in routine to check the
permanent bit of the entry. If it shows the entry is a
Permanent entry, it is not updated. Non-permanent entries
will be updated as normal.
The Port Configure Extended register enables or disables
Multicast Address processing. When DA processing is
enabled in the PTARG register, the default is for Multicast
and Broadcast frames to be ignored (no DA processing)
thus causing them to be forwarded at all times. If the user
wishes Multicast frames to be processed in the same way
as Unicast frames, bit 1 should be set to 1. Bit 0 allows the
user to set a default action for cases when Multicast
processing is enabled but a matching Group Address was
not found in the LANCAM. Additionally, Multicast
frames may have their SAs processed by setting bit 2 to 1.
Table 25: PCFG_EXT: Port Configure Extended Register Mapping
Name
Bits
Description
Default_Multicast_Action
0
If a DA processing function is performed on a Multicast group address, the packet is treated in the
following way if the DA is not found in the LANCAM database:
0 = Drop. The REJ signal is asserted. This will inform external hardware (MAC) that the Multicast
packet should be rejected (not forwarded).
1 = Pass. The REJ signal is not asserted.
Bit 1 must be set; otherwise no Multicast DA processing function is performed.
DA_Processing_Enable
SA_Processing_Enable
Permanent_Check
1
2
3
0 = Disable. Multicast DAs are not processed
1 = Enable. Multicast DAs are processed in the same way as Unicast DAs
0 = Disable. SAs from a packet deemed to have a Multicast DA are not processed.
1 = Enable. SAs from a packet deemed to have a Multicast DA are processed.
0 = The permanent bit of a matching MAC address will not be checked during the SA Learn built-in
routine.
1 = The SA Learn routine will read the associated data of the matching LANCAM entry to check the
Permanent bit. If set, the SA will not be updated. If not set, the entry will be updated as normal.
RESERVED
[15:4] Reserved = Write as 0H. When reading, these bits will read as 0H
Rev. 0a
17
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