Texas Instruments Development Kit for TM4C129x,Tiva™ ARM® Cortex™ -M4 Microcontroller DK-TM4C129X DK-TM4C129X Datenbogen
Produktcode
DK-TM4C129X
Register 8: Ethernet MAC VLAN Tag (EMACVLANTG), offset 0x01C
The Ethernet MAC VLAN Tag (MACVLANTG) register contains the IEEE 802.1Q VLAN Tag to
identify the VLAN frames. The MAC compares the 13th and 14th bytes of the receiving frame
(Length/Type) with the value 0x8100, and the following two bytes are compared with the VLAN tag.
If a match occurs, the MAC sets the received VLAN bit in the receive frame status. The legal length
of the frame is increased from 1,518 bytes to 1,522 bytes.
identify the VLAN frames. The MAC compares the 13th and 14th bytes of the receiving frame
(Length/Type) with the value 0x8100, and the following two bytes are compared with the VLAN tag.
If a match occurs, the MAC sets the received VLAN bit in the receive frame status. The legal length
of the frame is increased from 1,518 bytes to 1,522 bytes.
Ethernet MAC VLAN Tag (EMACVLANTG)
Base 0x400E.C000
Offset 0x01C
Type RW, reset 0x0000.0000
Offset 0x01C
Type RW, reset 0x0000.0000
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
ETV
VTIM
ESVL
VTHM
reserved
RW
RW
RW
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Type
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reset
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
VL
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
Type
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reset
Description
Reset
Type
Name
Bit/Field
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
RO
reserved
31:20
VLAN Tag Hash Table Match Enable
Description
Value
The VLAN Hash Match operation is not performed.
0
The most significant four bits of the VLAN tag's CRC are used
to index the content of the MAC VLAN Hash Table
(EMACVLANHASH) register. A value of 1 in the
EMACVLANHASH register, corresponding to the index,
indicates that the frame matched the VLAN hash table.
to index the content of the MAC VLAN Hash Table
(EMACVLANHASH) register. A value of 1 in the
EMACVLANHASH register, corresponding to the index,
indicates that the frame matched the VLAN hash table.
When Bit 16 (
ETV
) is set, the CRC of the 12-bit VLAN Identifier
(VID) is used for comparison whereas when
ETV
is reset, the
CRC of the 16-bit VLAN tag is used for comparison.
1
0
RW
VTHM
19
Enable S-VLAN
Description
Value
The MAC transmitter does not recognize S-VLAN frames as
valid VLAN tagged frames.
valid VLAN tagged frames.
0
The MAC transmitter and receiver considers the S-VLAN (Type
= 0x88A8) frames as valid VLAN tagged frames.
= 0x88A8) frames as valid VLAN tagged frames.
1
0
RW
ESVL
18
1681
December 13, 2013
Texas Instruments-Advance Information
Tiva
™
TM4C129XNCZAD Microcontroller