DS537 Datasheet, PDF (73/148 Pages) Xilinx, Inc – LogiCORE IP XPS LL TEMAC

LogiCORE IP XPS LL TEMAC (v2.03a)
Table 50: Transmit LocalLink Header Word 4 (APP1)
Bit(s)
Name
Description
(Msb)
0 - 15
TX_CSBEGIN
Transmit Checksum Calculation Starting Point. This value is the offset to the location in the
frame to the first byte that needs to be included in the checksum calculation. The first byte is
indicated by a value of zero. The beginning position must be 16-bit aligned.
16 - 31
(Lsb)
TX_CSINSERT
Transmit Checksum Insertion Point. This value is the offset to the location in the frame where
the checksum value should be written into the TCP or UDP segment header. The value must be
16-bit aligned and cannot be in the first 8 bytes of the frame.
Table 51: Transmit LocalLink Header Word 5 (APP2)
Bit(s)
Name
Description
(Msb)
0 - 15
Reserved
Undefined value.
16 - 31
(Lsb)
TX_CSINIT
Transmit Checksum Calculation Initial Value. This value is a 16-bit seed that cane be used
to insert the TCP or UDP pseudo header into the checksum calculation. See TCP/UDP
Checksum Off Load in Hardware, page 69 for more information on using this field.
Receive LocalLink Frame Format
The receive LocalLink frame always contains one 32-bit header word and eight 32-bit footer words (words 0 to 7).
Of these words, only footer words 3 through 7 are populated with values by the XPS_LL_TEMAC. Table 54,
Table 55, and Table 56 show the definitions of these words. Reserve fields do not have defined values.
If the parameter C_TEMAC_RXCSUM is “0”, the receive checksum off load function is not included in the build
and receive LocalLink footer word 7 will always be zero. If C_TEMAC_RXCSUM is “1”, the raw checksum will be
calculated for every frame received and will be placed in receive LocalLink footer word 7. For more information
about using the receive raw checksum value, please see "TCP/UDP Checksum Off Load in Hardware,".
Receive LocalLink footer word 7 will always contain the number of bytes in length of the frame being sent across
the receive LocalLink interface.
The TemacLlink_REM(3:0) bus is used to indicate how many bytes in the last 32-bit word of the payload are valid
data. The bus is used as a mask with a "0" indicating that the byte is valid. For example, TemacLlink_REM(0:3) =
"0111" would indicate that only the first byte of the last word of the payload [TemacLlink_Data(0:7)] is valid and the
remaining three bytes are unused. TemacLlink_REM(0:3) = "0011" would indicate that the first two bytes of the last
word of the payload [TemacLlink_Data(0:15)] are valid and the remaining two bytes are unused.
Table 52: Receive LocalLink Footer Word 3 (APP0)
Bit(s)
Name
Description
(Msb)
0
STS/CTRL
Undefined value.
1 - 15
Reserved
Undefined value.
16 - 31
(Lsb)
MCAST_ADR_U
Multicast Address (47:32). These are the upper 16 bits of the multicast destination address of
this frame. This value is only valid if Footer word 5 bit 31 is a 1. The address is ordered so the
first byte received is the lowest positioned byte in the register; for example, MAC address of
AA-BB-CC-DD-EE-FF would be stored in UnicastAddr(47:0) as 0xFFEEDDCCBBAA. This word
would be 0xFFEE.
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