Datasheet
2016 Microchip Technology Inc. DS00002246A-page 75
KSZ8895MQX/RQX/FQX/MLX
4.4 Static MAC Address Table
KSZ8895MQX/RQX/FQX/MLX has a static and a dynamic address table. When a DA look-up is requested, both tables
will be searched to make a packet forwarding decision. When an SA look-up is requested, only the dynamic table is
searched for aging, migration, and learning purposes. The static DA look-up result will have precedence over the
dynamic DA look-up result. If there are DA matches in both tables, the result from the static table will be used. The static
table can only be accessed and controlled by an external SPI master (usually a processor). The entries in the static table
will not be aged out by KSZ8895MQX/RQX/FQX/MLX. An external device does all addition, modification and deletion.
Please note that register bit assignments are different for static MAC table reads and static MAC table write, as shown
in Table 4-6 and Tab le 4- 7.
TABLE 4-6: FORMAT OF STATIC MAC TABLE FOR READS
Address Name Description Mode Default
Format of Static MAC Table for Reads (32 entries)
63 - 57 FID
Filter VLAN ID, representing one of the 128 active
VLANs
RO 0000000
56 Use FID
1, use (FID+MAC) to look-up in static table.
0, use MAC only to look-up in static table.
RO 0
55 Reserved Reserved. RO N/A
54 Override
1, override spanning tree “transmit enable = 0” or
“receive enable = 0” setting. This bit is used for span-
ning tree implementation.
0, no override.
RO 0
53 Valid
1, this entry is valid, the look-up result will be used.
0, this entry is not valid.
RO 0
52 - 48
Forwarding
Ports
The 5 bits control the forward ports, example:
00001, forward to Port 1
00010, forward to Port 2
….
10000, forward to Port 5
00110, forward to Port 2 and Port 3
11111, broadcasting (excluding the ingress port)
RO 00000
47 - 0
MAC
Address (DA)
48 bit MAC address. RO 0x0
TABLE 4-7: FORMAT OF STATIC MAC TABLE FOR WRITES
Address Name Description Mode Default
Format of Static MAC Table for Writes (32 entries)
62 - 56 FID
Filter VLAN ID, representing one of the 128 active
VLANs.
W 0000000
55 Use FID
1, use (FID+MAC) to look-up in static table.
0, use MAC only to look-up in static table.
W0
54 Override
1, override spanning tree “transmit enable = 0” or
“receive enable = 0” setting. This bit is used for span-
ning tree implementation.
0, no override.
W0
53 Valid
1, this entry is valid, the look-up result will be used.
0, this entry is not valid.
W0