KSZ8842-16_08 Datasheet, PDF (119/141 Pages) Micrel Semiconductor – 2-Port Ethernet Switch with Non-PCI Interface

Micrel, Inc.
KSZ8842-16/32 MQL/MVL/MVLI/MBL
Static MAC Address Table
The KSZ8842M supports both a static and a dynamic MAC address table. In response to a Destination Address (DA) look
up, The KSZ8842M searches both tables to make a packet forwarding decision. In response to a Source Address (SA)
look up, only the dynamic table is searched for aging, migration and learning purposes.
The static DA look up result takes precedence over the dynamic DA look up result. If there is a DA match in both tables,
the result from the static table is used. These entries in the static table will not be aged out by the KSZ8842M.
Bit
57-54
53
52
51
50-48
47-0
Default Value R/W
0000
RW
0
R/W
0
R/W
0
R/W
000
R/W
0
R/W
Description
FID
Filter VLAN ID - identifies one of the 16 active VLANs.
Use FID
1: specifies the useof FID+MAC for static table look ups
0: specifies only the use of MAC for static table look ups
Override
1: overrides the port setting “transmit enable = 0” or “receive enable = 0” setting.
0: specifies no override
Valid
1: specifies that this entry is valid, the look up result will be used
0: specifies that this entry is not valid
Forwarding ports
These 3 bits control the forwarding port(s):
000: no forward
001: forward to port 1
010: forward to port 2
100: forward to port 3
011: forward to port 1 and port 2
110: forward to port 2 and port 3
101: forward to port 1 and port 3
111: broadcasting (excluding the ingress port)
MAC address
48 bits MAC Address
Table 18. Static MAC Table Format (8 Entries)
Static MAC Table Lookup Examples:
1. Static Address Table Read (read the second entry at indirect address offset 0x01)
Write to reg. IACR with 0x1001 (set indirect address and trigger a read static MAC table operation)
Then
Read reg. IADR3 (static MAC table bits 57-48)
Read reg. IADR2 (static MAC table bits 47-32)
Read reg. IADR5 (static MAC table bits 31-16)
Read reg. IADR4 (static MAC table bits 15-0)
2. Static Address Table Write (write the eighth entry at indirect address offset 0x07)
Write to reg. IADR3 (static MAC table bits 57-48)
Write to reg. IADR2 (static MAC table bits 47-32)
Write to reg. IADR5 (static MAC table bits 31-16)
Write to reg. IADR4 (static MAC table bits 15-0)
Write to reg. IACR with 0x0007 (set indirect address and trigger a write static MAC table operation)
October 2007
119
M9999-102207-1.9