LAN9500 Datasheet, PDF (169/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

7.4.9 VLAN1 TAG REGISTER (VLAN1)
Address:
120h
LAN950x
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 TLI is empty.
Bits
31:16
15:0
Description
RESERVED
VLAN1 Tag Identifier (VTI1)
This contains the VLAN Tag field to identify the VLAN1 frames. This field is
compared with the 13^th and 14^th bytes of the incoming frames for VLAN1
frame detection.
Type
RO
R/W
Default
-
FFFFh
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DS00001875A-page 169