![ARTERY AT32F435 Series Reference Manual Download Page 616](http://html1.mh-extra.com/html/artery/at32f435-series/at32f435-series_reference-manual_2977592616.webp)
AT32F435/437
Series Reference Manual
2022.11.11
Page 616
Rev 2.03
26.3.8 Ethernet MAC VLAN tag register (EMAC_MACVLT)
The Ethernet MAC VLAN tag register contains the IEEE 802.1Q VLAN tag to identify the VLAN frames.
The MAC compares the 13th and 14th bytes of the received frame (length/type) with 16’h8100, and the
following 2 bytes are compared with the VLAN tag. If the comparison matches, the VLAN bit is set in
the receive frame status. The legal length of the VLAN frame is increased from 1518 bytes to 1522
bytes.
If the EMAC_MACVLT register is configured to be double-synchronized to the (G)MII clock domain,
then consecutive write operations to this register should be performed at least four clock cycles in the
destination clock domain.
Bit
Register
Reset value
Type
Description
Bit 31: 17 Reserved
0x0000
resd
Kept at its default value.
Bit 16
ETV
0x0
ro
Enable 12-bit VLAN tag comparison)
When this bit is set, a 12-bit VLAN identifier, rather than a
16-bit VLAN tag, is used for comparison and filtering. The
bit [11: 0] of the VLAN tag is compared with the
corresponding filed in the received VLAN-tagged frame.
Similarly, if enabled, only a 12-bit VLAN tag is used for
hash VLAN filtering.
When this bit is cleared, the 16 bits of the received VLAN
frame’s 15
th
and 16
th
bytes are used for comparison and
VLAN hash filtering.
Bit 15: 0
VTI
0x0000
rw
VLAN Tag Identifier (for receive frames)
This field contains the 802.1Q VLAN tag to identify VLAN
frames, which is compared with the 15
th
and 16
th
bytes of
the received VLAN frames, described as follows:
Bit [15: 13]: User priority
Bit 12: Canonical format indicator (CFI) or drop eligible
indicator (DEI)
Bit [11: 0]: VLAN tag’s VLAN identifier field
When the ETV bit is set, only the VID ([11: 0]) is used for
comparison. If the VL is all zero (if the ETV is set, then
VL[11: 0] is all zero), the MAC does not check the 15
th
and
16
th
bytes for VLAN tag comparison, and treats all frames
with a type field value of 0x8100 or 0x88a8 as VLAN
frames.
26.3.9 Ethernet MAC remote wakeup frame filter register
(EMAC_MACRWFF)
The PMT CSR sets the request wakeup events and detects the wakeup events.
Figure 26- 1 Ethernet MAC rem ote wakeup frame filter register (EMAC_MACRW FF)
Wkuppktfilter_reg0
Wkuppktfilter_reg1
Wkuppktfilter_reg4
Wkuppktfilter_reg2
Wkuppktfilter_reg3
Wkuppktfilter_reg5
Wkuppktfilter_reg7
Wkuppktfilter_reg6
Filter 0 Byte Mask
Filter 1 Byte Mask
Filter 2 Byte Mask
Filter 3 Byte Mask
RESD
RESD
RESD
Filter 0
Cmd
Filter 1
Cmd
Filter 2
Cmd
Filter 3
Cmd
RESD
Filter 3 Offset
Filter 2 Offset
Filter 1 Offset
Filter 0 Offset
Filter 1 CRC-16
Filter 0 CRC-16
Filter 3 CRC-16
Filter 2 CRC-16