SMSC LAN9312 - Manual (Page 282)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
Revision 1.4 (08-19-08) 282 SMSC LAN9312
DATASHEET
14.3.10 Host MAC VLAN2 Tag Register (HMAC_VLAN2)
This read/write register contains the VLAN tag field to identify VLAN2 frames. When a VLAN2 frame
is detected, the legal frame length is increased from 1518 bytes to 1538 bytes. Refer to
Section 9.3,
"Virtual Local Area Network (VLAN) Support," on page 113 for additional information.
Offset: Ah Size: 32 bits
BITS DESCRIPTION TYPE DEFAULT
31:16 RESERVED RO -
15:0 VLAN2 Tag Identifier (VTI2)
This field contains the VLAN Tag used to identify VLAN2 frames. This field
is compared with the 13th and 14th bytes of the incoming frames for VLAN2
frame detection.
Note: If used, this register is typically set to the standard VLAN value of
8100h. If both VLAN1 and VLAN2 Tag Identifiers are used, they
should be unique. If both are set to the same value, VLAN1 is
given higher precedence and the maximum legal frame length is
set to 1522.
R/W FFFFh