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Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
Chapter 7:
GTP Receiver (RX)
R
Description
Enabling Comma Alignment
To enable the comma alignment block, the RXCOMMADETUSE port is driven High.
RXCOMMADETUSE is driven Low to bypass the block completely for minimum latency.
Configuring Comma Patterns
To set the comma pattern that the block searches for in the incoming data stream, the
MCOMMA_10B_VALUE, PCOMMA_10B_VALUE, and COMMA_10B_ENABLE
attributes are used. The length of the commas depends on the INTDATAWIDTH of the tile
(see
shows how the COMMA_10B_ENABLE
masks each of the comma values to allow partial pattern matching.
shows how a COMMA is combined with COMMA_ENABLE to make a
wildcarded comma for a 10-bit internal comma.
If COMMA_DOUBLE is TRUE, the MCOMMA and PCOMMA patterns are combined so
that the block searches for two commas in a row. The number of bits in the comma depends
on INTDATAWIDTH (see
shows how the
commas are combined when COMMA_DOUBLE is TRUE.
PCOMMA_DETECT_0
PCOMMA_DETECT_1
Control raising of RXCOMMADET on comma plus.
FALSE: Do not raise RXCOMMADET when comma plus is detected.
TRUE: Raise RXCOMMADET when comma plus is detected. (This setting does
not affect comma alignment.)
RX_SLIDE_MODE_0
RX_SLIDE_MODE_1
Selects between sliding in the PMA or in the PCS.
Legal values are PCS (default) and
PMA.
Table 7-21:
RX Comma Alignment and Detection Attributes
(Continued)
Attribute
Description
Figure 7-12:
Comma Pattern Masking
Figure 7-13:
Extended Comma Pattern Definition
0101111100
xxx1111100
0001111111
MCOMMA_10B_
V
ALUE
or
PCOMMA_10B_
V
ALUE
Pattern re
qu
ired
for comma detection
(x = don’t care)
COMMA_10B_E
N
ABLE
UG196_c7_12_092606
MCOMMA_10B_
V
ALUE
PCOMMA_10B_
V
ALUE
UG196_c7_13_092606