Xilinx Virtex-5 RocketIO GTP User Manual page 151

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Table 7-21
Table 7-21: RX Comma Alignment and Detection Attributes
Attribute
ALIGN_COMMA_WORD_0
ALIGN_COMMA_WORD_1
COMMA_10B_ENABLE_0
COMMA_10B_ENABLE_1
COMMA_DOUBLE_0
COMMA_DOUBLE_1
MCOMMA_10B_VALUE_0
MCOMMA_10B_VALUE_1
MCOMMA_DETECT_0
MCOMMA_DETECT_1
PCOMMA_10B_VALUE_0
PCOMMA_10B_VALUE_1
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
defines the RX comma alignment and detection attributes.
Controls alignment of detected commas within a multi-byte datapath.
1: Align comma to either byte within a two-byte datapath. The comma can be
aligned to either the even byte [9:0] or the odd byte [19:10] of RXDATA at the
FPGA when the two-byte RX interface is selected.
2: Align comma to the even byte within a two-byte datapath. The aligned comma
is guaranteed to be aligned to byte RXDATA [9:0]. For
ALIGN_COMMA_WORD = 2 to work properly in conjunction with the elastic
buffer, both CLK_COR_ADJ_LEN and CLK_COR_MIN_LAT must be even.
Protocols that send commas in even and odd positions must set
ALIGN_COMMA_WORD to 1.
If RXDATAWIDTH is reset to 0, ALIGN_COMMA_WORD must be set to 1.
Sets which bits of MCOMMA/PCOMMA must be matched to incoming data and
which bits can be any value.
This attribute is a 10-bit mask with a default value of 1111111111. Any bit in the
mask that is reset to 0 effectively turns the corresponding bit in MCOMMA or
PCOMMA to a don't care bit.
Specifies whether a comma match consists of either a comma plus or a comma
minus alone, or whether both are required in the sequence.
FALSE: The plus comma (PCOMMA) and minus comma (MCOMMA) are
handled separately. An individual match for either can lead to comma detection
and alignment.
TRUE: A comma match consists of a comma plus followed immediately by a
comma minus. The match pattern is 20 or 16 bits (as determined by
INTDATAWIDTH).
When COMMA_DOUBLE is TRUE, PCOMMA_DETECT should be the same as
MCOMMA_DETECT, and RXENPCOMMAALIGN should be the same as
RXENMCOMMAALIGN.
Define comma minus to raise RXCOMMADET and align the parallel data.
Reception order is right to left. (MCOMMA_10B_VALUE[0] is received first.) The
default value is 1010000011 (K28.5). This definition does not affect 8B/10B
encoding or decoding.
Control raising of RXCOMMADET on comma minus.
FALSE: Do not raise RXCOMMADET when comma minus is detected.
TRUE: Raise RXCOMMADET when comma minus is detected. (This setting
does not affect comma alignment.)
Define comma plus to raise RXCOMMADET and align the parallel data.
Reception order is right to left. (PCOMMA_10B_VALUE[0] is received first.) The
default value is 0101111100 (K28.5). This definition does not affect 8B/10B
encoding or decoding.
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Configurable Comma Alignment and Detection
Description
151