Altera 100G Interlaken MegaCore Function - Manual (Page 42)

data symbol contain valid data and the remaining words do not contain valid data, and that in the second
of these two words, only the three most significant bytes contain valid data.
In Interleaved Mode, you can transfer a packet without interleaving as long as the channel number does
not toggle during the same packet transfer. However, you must still assert the
itx_sob
and
itx_eob
signals correctly to maintain the proper burst boundaries.
If you do not drive the
itx_sob
and
itx_eob
signals, the 100G Interlaken IP Core does not operate
properly and the transmit FIFO may overflow, since in this mode the internal logic is looking for
itx_sob
and
itx_eob
assertion for insertion of proper burst control words.
100G Interlaken IP Core Packet Mode Operation Example
Figure 4-6: Packet Transfer on Transmit Interface in Packet Mode
This example illustrates the expected behavior of the 100G Interlaken IP core application interface
transmit signals during a packet transfer in single segment packet mode.
tx_usr_clk
itx_sop[1]
itx_chan
itx_sob[1]
itx_eob
itx_din_words
itx_num_valid[7:4]
itx_eopbits
itx_ready
itx_calendar
Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 6 Cycle 7 Cycle 8 Cycle 9
8’h2
d1 d2 d3
4’b1000 4’b1000 4’b0111
4’b0000 4’b1011
64’hffff_ffff_ffff_ffff 64’h1111_2222_3333_4444
The figure illustrates a packet mode data transfer of 179 bytes on the transmit interface into the IP core. In
this mode, the 100G Interlaken IP core ignores the
itx_sob
and
itx_eob
input signals.
To start a transfer, you assert
itx_sop[1]
when you have data ready on
itx_din_words
. At the following
rising edge of the clock, the IP core detects that
itx_sop[1]
is asserted, indicating that the value on
itx_din_words
in the current cycle is the start of an incoming data packet. When you assert
itx_sop[1]
,
you must also assert the correct value on
itx_chan
to tell the IP core the data channel source of the data.
In this example, the value 2 on
itx_chan
tells the IP core that the data originates from channel number 2.
4-12 100G Interlaken IP Core Packet Mode Operation Example
UG-01128
2015.05.04
Altera Corporation Functional Description
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