DS537 Datasheet, PDF (72/148 Pages) Xilinx, Inc – LogiCORE IP XPS LL TEMAC

LogiCORE IP XPS LL TEMAC (v2.03a)
X-Ref Target - Figure 47
LlinkTemac_CLK
LlinkTemac_RST
TemacLlink_Data(0:31)
HDR Payload (variable)
Footer
TemacLlink_SRC_RDY_n
LlinkTemac_DST_RDY_n
TemacLlink_REM(0:3)
REM REM
REM
REM
TemacLlink_SOF_n
TemacLlink_SOP_n
TemacLlink_EOP_n
TemacLlink_EOF_n
DS537_47_091909
Figure 47: Typical Waveform of LocalLink Receive Ethernet Frame
Transmit LocalLink Frame Format
The transmit LocalLink frame always contains eight 32-bit header words (words 0 to 7) and one 32-bit footer word.
Of these words, only header words 3, 4, and 5 are used by the XPS_LL_TEMAC. Table 49, Table 50, and Table 51
show the definitions of these words. The footer word is ignored.
If the transmit LocalLink header word 3 bit 31 is "0" (TX_CSCNTRL is disabled) or if the parameter
C_TEMAC_TXCSUM is "0" (the transmit checksum off load function is not included in build), then none of the
transmit LocalLink header words are used and no transmit checksum off load will take place.
If the parameter C_TEMAC_TXCSUM is "1", then transmit checksum off load can be controlled on a frame by frame
basis by setting or clearing the transmit LocalLink Header word 3 bit 31(TX_CSCNTRL).
For more details about how the transmit LocalLink header words are used for transmit checksum off load, please
see TCP/UDP Checksum Off Load in Hardware, page 69.
The LlinkTemac_REM(0:3) 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, LlinkTemac_REM(0:3) =
"0111" would indicate that only the first byte of the last word of the payload [LlinkTemac_Data(0:7)] is valid and the
remaining three bytes are unused. LlinkTemac_REM(0:3) = "0011" would indicate that the first two bytes of the last
word of the payload [LlinkTemac_Data(0:15)] are valid and the remaining two bytes are unused.
Table 49: Transmit LocalLink Header Word 3 (APP0)
Bit(s)
Name
Description
(Msb)
0 - 30
Reserved
Undefined value.
31
(Lsb)
TX_CSCNTRL
Transmit Checksum Enable.
0 - no transmit checksum off load for this frame
1 - perform transmit checksum off load for this frame if enabled by the C_TEMAC_TXCSUM
parameter
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