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AT32F435/437
Series Reference Manual
2022.11.11
Page 601
Rev 2.03
26.2.4 Enter and wake up EMAC power-down mode
The EMAC enters power-off mode when the PD bit is enabled in the EMAC_MACPMTCTRLSTS register.
In this mode, all received frames are dropped by the EMAC and they are not forwarded to the application.
PMT supports the reception of remote wakeup frames and AMD Magic Packet frames and uses them to
wake up the EMAC from power-off mode. This is done by setting the ERWF and EMP bits in the
EMAC_MACPMTCTRLSTS register.
Remote wakeup frame filter register
There are eight wakeup frame filter registers, each of which requires to be configured one by one. The
desired values of the wakeup frame filter are loaded by sequentially loading eight times the wakeup
frame filter register. The read operation is identical to the write operation. To read the eight values, the
user has to read the wakeup frame filter register for consecutive eight times.
Figure 26-14 W akeup fram e filter register
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
Filter I byte mask
This register defines which bytes of the filter i (i=0~3) are used to determine whether or not the frame is
a wakeup frame. The bit 31 must be zero. The bit j[30: 0] is the byte mask. If the bit j is set, then filter i
j of the incoming frame will be processed by the CRC block, otherwise filter i j is ignored.
Filter i command
This is a 4-bit command. Bit 3 defines the address type. When the bit is set, this feature applies to only
multicast addresses. When the bit is cleared, this feature applies to only unicast addresses. Bit 2 and bit
1 are reserved. Bit 0 is the filter enable bit. This filter is disabled if the bit 0 is cleared.
Filter i offset
This is an 8-bit register that defines the offset for the filter i first byte to be examined by filter i. The
minimum allowed is 12, which refers to the 13
th
byte of the frame (offset value 0 means the first byte of
the frame)
Filter i CRC-16
This register contains the CRC_16 value calculated by the filter, and the byte mask value programmed
in the wakeup frame filter register block.
Remote wakeup frame detection
This mode is enabled by setting the RRWF bit in the EMAC_MACPMTCTRLSTS register.
PMT supports four programmable filters. If the incoming frame passed the address filtering of the filter,
and if the filter CRC_16 matches the examined incoming frame, then the wakeup frame is received. PMT
is only responsible for checking length error, FCS error, Dribble bit error, MII error, collision and ensuring
that the wakeup frame is not a runt frame.
When a remote wakeup frame is received, the EMAC will move from sleep mode to normal mode. At the