KSZ8873FLLI Micrel Inc, KSZ8873FLLI Datasheet - Page 83

• Manufacturer Part Number: KSZ8873FLLI
• Description: IC ETHERNET SWITCH 3PORT 64LQFP
• Manufacturer: Micrel Inc

Specifications of KSZ8873FLLI

• Controller Type: Ethernet Switch Controller
• Interface: MII
• Voltage - Supply: 1.8V, 2.5V, 3.3V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed
• Other names: 576-3632; KSZ8873FLLI

Micrel, Inc.
VLAN Table
The KSZ8873 uses the VLAN table to perform look ups. If 802.1Q VLAN mode is enabled (register 5, bit 7 = 1), this table
will be used to retrieve the VLAN information that is associated with the ingress packet. This information includes FID
(filter ID), VID (VLAN ID), and VLAN membership as described in the following table.
If 802.1Q VLAN mode is enabled, KSZ8873 will assign a VID to every ingress packet. If the packet is untagged or tagged
with a null VID, the packet is assigned with the default port VID of the ingress port. If the packet is tagged with non null
VID, the VID in the tag will be used. The look up process will start from the VLAN table look up. If the VID is not valid, the
packet will be dropped and no address learning will take place. If the VID is valid, the FID is retrieved. The FID+DA and
FID+SA lookups are performed. The FID+DA look up determines the forwarding ports. If FID+DA fails, the packet will be
broadcast to all the members (excluding the ingress port) of the VLAN. If FID+SA fails, the FID+SA will be learned.
Examples:
September 2010
1. VLAN Table Read (read the 3
2. VLAN Table Write (write the 7
Bit
19
18-16
15-12
11-0
Then,
Write to reg. 121 (0x79) with 0x14
Write to reg. 122 (0x7A) with 0x02
Read reg. 129 (0x81), VLAN table bits [19:16]
Read reg. 130 (0x82), VLAN table bits [15:8]
Read reg. 131 (0x83), VLAN table bits [7:0]
Write to reg. 129 (0x81), VLAN table bits [19:16]
Write to reg. 130 (0x82), VLAN table bits [15:8]
Write to reg. 131 (0x83), VLAN table bits [7:0]
Write to reg. 121 (0x79) with 0x04
Write to reg. 122 (0x7A) with 0x06
Name
Valid
Membership
FID
VID
R/W
R/W
R/W
R/W
R/W
Table 16. Format of Static VLAN Table (16 Entries)
rd
th
entry)
Description
= 1, entry is valid
= 0, entry is invalid
Specify which ports are members of the VLAN. If
a DA lookup fails (no match in both static and
dynamic tables), the packet associated with this
VLAN will be forwarded to ports specified in this
field. For example, 101 means port 3 and 1 are in
this VLAN.
Filter ID. KSZ8873 supports 16 active VLANs
represented by these four bit fields. FID is the
mapped ID. If 802.1Q VLAN is enabled, the look
up will be based on FID+DA and FID+SA.
IEEE 802.1Q 12 bits VLAN ID
entry)
83
// Read VLAN table selected
// Trigger the read operation
// Write VLAN table selected
// Trigger the write operation
Default
1
111
0x0
0x001
KSZ8873MLL/FLL/RLL
M9999-092309-1.2