Altera 100G Interlaken MegaCore Function - Manual (Page 39)

You must enforce the following additional constraints in sending dual segment traffic to the TX user data
transfer interface:
• The application can start a packet or burst transfer in a single cycle on only one of the most significant
byte (Byte 63) or the middle position (Byte 31) in the 512-bit data symbol. Therefore, the application
can assert only one of
itx_sop[1]
and
itx_sop[0]
, and only one of
itx_sob[1]
and
itx_sob[0]
, in
a given cycle. This constraint ensures that the minimum number of idle and data bytes between
consecutive starts of packet or burst is at least 64.
• The application can end a packet or burst transfer only once in a single cycle. Therefore, the minimum
number of idle and data bytes between consecutive ends of packet or burst must be at least 64.
The same constraints apply to dual segment traffic on the RX user data transfer interface: the minimum
number of idle and data bytes between consecutive starts of packet or burst must be at least 64, and the
minimum number of idle and data bytes between consecutive ends of packet or burst must be at least 64.
The 100G Interlaken IP core enforces these constraints on the RX user data transfer interface.
Figure 4-4: Dual Segment Data Transfer
In a dual segment data transfer, the end of one data burst and the start of another can appear in the same
clock cycle. In this example, each column represents a single 512-bit data symbol, divided into 64-bit
words, and each color represents a separate data burst. The second and third data bursts are dual segment
transfers.
Word 7 (bits [511:448])
Word 6 (bits [447:384])
Word 5 (bits [383:320])
Word 4 (bits [319:256])
Word 3 (bits [255:192])
Word 2 (bits [191:128])
Word 1 (bits [127:64])
Word 0 (bits [63:0])
Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 6 Cycle 7
dw8
dw0
dw1
dw2
dw3
dw0
dw1
dw2
dw3
dw4
dw5
dw6
dw7 dw4
dw5
dw6
dw7
dw8
dw9
dw10
dw11 dw12
dw13
dw14
dw15
dw16
dw17
dw18
dw19 dw20
dw21
dw22
dw23
dw0
dw1
dw2
dw3 dw4
dw5
dw6
dw7
dw8
Eight-word data symbol::
Related Information
• Data Format on page 3-6
• 100G Interlaken IP Core User Data Transfer Interface Signals on page 5-4
• 100G Interlaken IP Core Dual Segment Interleaved Data Transfer Transmit Example on page 4-
15
Example of dual segment data transfers on the TX user data transfer interface.
• 100G Interlaken IP Core Dual Segment Interleaved Data Transfer Receive Example on page 4-22
Example of dual segment data transfers on the RX user data transfer interface.
UG-01128
2015.05.04
Dual Segment Mode 4-9
Functional Description Altera Corporation
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