Altera 100G Interlaken MegaCore Function User Manual
Page 53
In cycle 2, the following two events occur:
• The first data burst completes. The IP core asserts
irx_eob
, indicating the data the IP core transfers to
the application in this clock cycle is the end of the burst. The value the IP core drives on
irx_num_valid[7:4]
indicates that one word in this data symbol is valid data associated with this
burst. In addition, the IP core drives
irx_eopbits
to the value of 4'b0000 to indicate that the data the
IP core transfers to the application in this clock cycle is not the end of the packet.
• A second data burst starts at Word 3, as is allowed in dual segment mode. The IP core asserts
irx_sop[0]
and
irx_sob[0]
, indicating that this cycle is both the start of the burst and the start of the
packet, and that data in this burst and packet starts from Byte 31 of the data symbol. The IP core drives
the value of 3 on
irx_chan
to indicate the data targets channel 3. The value of
irx_num_valid[3:0]
is
4'b0100, indicating this data transfer is a dual segment data transfer—that it begins at Word 3. The
value of
irx_num_valid[7:4]
has no relevance for the data words in this burst that appear in this data
symbol, except to indicate the previous burst includes no data in these words of the data symbol
(Words 3 through 0), and therefore, that they are available for the second data burst. As is required,
the dual segment data transfer places valid data in all four words in the least significant half of the data
symbol.
In cycles 3 and 4, the second data burst continues with no EOB or EOP indication. The application should
not sample the value of
irx_chan
in these clock cycles. The value on
irx_num_valid[7:4]
indicates that
all eight words in each of these data symbols are valid data associated with this burst.
In cycle 5, the following two events occur:
• The second data burst completes. The IP core asserts
irx_eob
, indicating the data transfered in this
clock cycle is the end of the burst. The value the IP core drives on
irx_num_valid[7:4]
indicates that
four words in this data symbol are valid data associated with this burst. In addition, the value the IP
core drives on
irx_eopbits
indicates the data is the end of the packet, and that all eight bytes of the
final data word are valid data bytes.
• A third data burst starts at Word 3, as is allowed in dual segment mode. The IP core asserts
irx_sob[0]
, indicating that this cycle is the start of the burst and that data in this burst starts from
Byte 31 of the data symbol. However, the IP core does not assert
irx_sop[0]
, indicating this burst is
not the first burst in the packet. The value the IP core drives on
irx_chan
indicates the data targets
channel 2. Therefore, we can conclude this data burst is the second burst in a packet that targets
channel 2. The value the IP core drives on
irx_num_valid[3:0]
is 4'b0100, indicating this data
transfer is a dual segment data transfer—that it begins at Word 3. The value of
irx_num_valid[7:4]
has no relevance for the data words in this burst that appear in this data symbol, except to indicate the
previous burst includes no data in these words of the data symbol (Words 3 through 0), and therefore,
that they are available for the second data burst. As is required, the dual segment data transfer places
valid data in all four words in the least significant half of the data symbol.
In cycle 6, the third data burst completes. The IP core asserts
irx_eob
, indicating the data transfered in
this clock cycle is the end of the burst. The value on
irx_num_valid[7:4]
indicates that five words in this
data symbol are valid data associated with this burst. In addition, the value the IP core drives on
irx_eopbits
indicates the data is the end of the packet, and that all eight bytes of the final data word are
valid data bytes. Because the data from this burst occupies words 7 through 3 of the data symbol, another
burst cannot start in the current data symbol.
By default, the RX user data transfer interface can generate interleaved data. However, the IP core can also
transfer a packet without interleaving—if the IP core does not toggle the channel number during the
UG-01128
2015.05.04
100G Interlaken IP Core Dual Segment Interleaved Data Transfer Receive Example
4-23
Functional Description
Altera Corporation