Xilinx Virtex-5 RocketIO GTP User Manual

152 www.xilinx.com 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 “Shared PMA PLL,” page 60). Figure 7-12 shows how the COMMA_10B_ENABLE
masks each of the comma values to allow partial pattern matching.
Figure 7-12 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 “Shared PMA PLL,” page 60). Figure 7-13 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_VALUE
or
PCOMMA_10B_VALUE
Pattern required
for comma detection
(x = don’t care)
COMMA_10B_ENABLE
UG196_c7_12_092606
MCOMMA_10B_VALUE PCOMMA_10B_VALUE
UG196_c7_13_092606

Xilinx Virtex-5 RocketIO GTP Specifications

General

Brand	Xilinx
Model	Virtex-5 RocketIO GTP
Category	Transceiver
Language	English