RM0090: Reference manual - STMicroelectronics

RM0090 Ethernet (ETH): media access control (MAC) with DMA controller
Figure 341. Wakeup frame filter register
Wakeup frame filter reg0
Wakeup frame filter reg1
Wakeup frame filter reg2
Wakeup frame filter reg3
Wakeup frame filter reg4
Wakeup frame filter reg5
Wakeup frame filter reg6
Wakeup frame filter reg7
RSVD
Filter 3
Command
● Filter i Byte Mask
This register defines which bytes of the frame are examined by filter i (0, 1, 2, and 3) in
order to determine whether or not the frame is a wakeup frame. The MSB (thirty-first
bit) must be zero. Bit j [30:0] is the Byte Mask. If bit j (byte number) of the Byte Mask is
set, then Filter i Offset + j of the incoming frame is processed by the CRC block;
otherwise Filter i Offset + j is ignored.
● Filter i Command
This 4-bit command controls the filter i operation. Bit 3 specifies the address type,
defining the pattern’s destination address type. When the bit is set, the pattern applies
to only multicast frames. When the bit is reset, the pattern applies only to unicast
frames. Bit 2 and bit 1 are reserved. Bit 0 is the enable bit for filter i; if bit 0 is not set,
filter i is disabled.
● Filter i Offset
This register defines the offset (within the frame) from which the frames are examined
by filter i. This 8-bit pattern offset is the offset for the filter i first byte to be examined.
The minimum allowed is 12, which refers to the 13th byte of the frame (offset value 0
refers to the first byte of the frame).
● Filter i CRC-16
This register contains the CRC_16 value calculated from the pattern, as well as the
byte mask programmed to the wakeup filter register block.
Remote wakeup frame detection
RSVD
Filter 0 Byte Mask
Filter 1 Byte Mask
Filter 2 Byte Mask
Filter 3 Byte Mask
Filter 2
Command
When the MAC is in sleep mode and the remote wakeup bit is enabled in the
ETH_MACPMTCSR register, normal operation is resumed after receiving a remote wakeup
frame. The application writes all eight wakeup filter registers, by performing a sequential
write to the wakeup frame filter register address. The application enables remote wakeup by
writing a 1 to bit 2 in the ETH_MACPMTCSR register. PMT supports four programmable
filters that provide different receive frame patterns. If the incoming frame passes the address
filtering of Filter Command, and if Filter CRC-16 matches the incoming examined pattern,
then the wakeup frame is received. Filter_offset (minimum value 12, which refers to the 13th
byte of the frame) determines the offset from which the frame is to be examined. Filter Byte
Mask determines which bytes of the frame must be examined. The thirty-first bit of Byte
Mask must be set to zero. The wakeup frame is checked only for length error, FCS error,
dribble bit error, MII error, collision, and to ensure that it is not a runt frame. Even if the
RSVD
Filter 1
Command
RSVD
Filter 0
Command
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
ai15647
Doc ID 018909 Rev 3 932/1416