Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface

Datasheet

4.4.9VLAN1 Tag Register (VLAN1)

Offset:

00A0h

Size:

32 bits

This register contains the VLAN tag field to identify VLAN1 frames. For VLAN frames the legal frame length is increased from 1518 bytes to 1522 bytes.

The RXCOE also uses this register to determine the protocol value to use to indicate the existence of a VLAN tag. When using the RXCOE, this value may only be changed if the RX path is disabled. If it is desired to change this value during run time, it is safe to do so only after the MAC is disabled and the MIL is empty.

BITS

DESCRIPTION

TYPE

DEFAULT

 

 

 

 

31:16

RESERVED

RO

-

 

 

 

 

15:0

VLAN1 Tag Identifier (VTI1)

R/W

FFFFh

 

This contains the VLAN Tag field to identify the VLAN1 frames. This field is

 

 

 

compared with the 13th and 14th bytes of the incoming frames for VLAN1

 

 

 

frame detection.

 

 

 

 

 

 

Revision 1.22 (09-25-08)

130

SMSC LAN9420/LAN9420i

 

DATASHEET