TM4C1294NCZAD Datasheet, PDF (1542/1914 Pages) Texas Instruments – Tiva Microcontroller

Ethernet Controller
Bit/Field
17:16
15:0
Name
VLC
VLT
Type
RW
RW
Reset
0x0
0x0
Description
VLAN Tag Control in Transmit Frames
Value Description
0x0 No VLAN tag deletion, insertion, or replacement
0x1 VLAN tag deletion
The MAC removes the VLAN type (bytes 13 and 14) and VLAN
tag (bytes 15 and 16) of all transmitted frames with VLAN tags.
0x2 VLAN tag insertion
The MAC inserts VLT in bytes 15 and 16 of the frame after
inserting the Type value (0x8100/0x88a8) in bytes 13 and 14.
This operation is performed on all transmitted frames,
irrespective of whether they already have a VLAN tag.
0x3 VLAN tag replacement
The MAC replaces VLT in bytes 15 and 16 of all VLAN-type
transmitted frames (Bytes 13 and 14 are 0x8100/0x88a8).
Note:
Changes to this field take effect only on the start of a frame.
If you write this register field when a frame is being
transmitted, only the subsequent frame can use the updated
value, that is, the current frame does not use the updated
value.
VLAN Tag for Transmit Frames
This field contains the value of the VLAN tag to be inserted or replaced.
The value must only be changed when the transmit lines are inactive
or during the initialization phase. Bits[15:13] are the User Priority, Bit
12 is the CFI/DEI, and Bits[11:0] are the VLAN tag's VID field.
1542
Texas Instruments-Production Data
June 18, 2014