Description; Enabling Clock Correction - Xilinx Virtex-5 RocketIO GTP User Manual

Chapter 7: GTP Receiver (RX)
Table 7-31: Clock Correction Attributes (Continued)
Attribute
CLK_COR_SEQ_1_1_0
CLK_COR_SEQ_1_1_1
CLK_COR_SEQ_1_2_0
CLK_COR_SEQ_1_2_1
CLK_COR_SEQ_1_3_0
CLK_COR_SEQ_1_3_1
CLK_COR_SEQ_1_4_0
CLK_COR_SEQ_1_4_1
CLK_COR_SEQ_1_ENABLE_0
CLK_COR_SEQ_1_ENABLE_1
CLK_COR_SEQ_2_1_0
CLK_COR_SEQ_2_1_1
CLK_COR_SEQ_2_2_0
CLK_COR_SEQ_2_2_1
CLK_COR_SEQ_2_3_0
CLK_COR_SEQ_2_3_1
CLK_COR_SEQ_2_4_0
CLK_COR_SEQ_2_4_1
CLK_COR_SEQ_2_ENABLE_0
CLK_COR_SEQ_2_ENABLE_1
CLK_COR_SEQ_2_USE_0
CLK_COR_SEQ_2_USE_1
RX_DECODE_SEQ_MATCH_0
RX_DECODE_SEQ_MATCH_1

Description

Enabling Clock Correction

Each GTP transceiver includes a clock correction circuit that performs clock correction by
controlling the pointers of the RX elastic buffer. To use clock correction, set RX_BUFFER to
TRUE to turn on the elastic buffer, and set CLK_CORRECT_USE to TRUE to turn on the
clock correction circuit.
172
The CLK_COR_SEQ_1 attributes are used in conjunction with
CLK_COR_SEQ_1_ENABLE to define clock correction sequence 1.
The sequence is made up of four subsequences. Each subsequence is 10 bits long.
The rules for setting the subsequences depend on INTDATAWIDTH and
RX_DECODE_SEQ_MATCH. See the
clock correction subsequences.
Not all subsequences need to be used. CLK_COR_DET_LEN determines how
many of the sequence are used for a match. If CLK_COR_DET_LEN = 1, only
CLK_COR_SEQ_1_1 is used.
CLK_COR_SEQ_1_ENABLE can be used to make parts of the sequence don't
cares. If CLK_COR_SEQ_1_ENABLE[k] is 0, CLK_COR_SEQ_1_k is a don't care
subsequence and is always a match.
The CLK_COR_SEQ_2 attributes are used in conjunction with
CLK_COR_SEQ_2_ENABLE to define the second clock correction sequence.
This second sequence is used as an alternate sequence for clock correction when
CLK_COR_SEQ_2_USE is TRUE: if either sequence 1 or sequence 2 arrives, clock
correction is performed.
The sequence is made up of four subsequences. Each subsequence is 10 bits long.
The rules for setting the subsequences depend on INTDATAWIDTH and
RX_DECODE_SEQ_MATCH. See the
clock correction subsequences.
Not all subsequences need to be used. CLK_COR_DET_LEN determines how
much of the sequence is used for a match. If CLK_COR_DET_LEN = 1, only
CLK_COR_SEQ_2_1 is used.
CLK_COR_SEQ_2_ENABLE can be used to make parts of the sequence don't
care. If CLK_COR_SEQ_2_ENABLE[k] is 0, CLK_COR_SEQ_2_k is a don't care
byte subsequence and is always a match.
Determines if the second clock correction sequence is to be used. When set to
TRUE, the second clock correction sequence also triggers clock correction.
Determines whether sequences are matched against the input to the 8B/10B
decoder or the output. Used for the clock correction circuit and the channel
bonding circuit.
TRUE: Sequences are matched against the output of the 8B/10B decoder. K
characters and disparity information is used. Bit ordering of the 8B/10B
output is used.
FALSE: Sequences are matched against unencoded data. Bit ordering is as for
an unencoded parallel interface.
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Description
"Description" section to learn how to set
"Description" section to learn how to set
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
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