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PRBS Detection
Overview
The GTP receiver includes a built-in Pseudo Random Bit Sequence (PRBS) checker. This
checker can be set to check for one of three industry-standard PRBS patterns. The checker
is self-synchronizing and works on the incoming data before comma alignment or
decoding. This function can be used to test the signal integrity of the channel.
Ports and Attributes
Table 7-18
Table 7-18: PRBS Detection Ports
Port
PRBSCNTRESET0
PRBSCNTRESET1
RXENPRBSTST0[1:0]
RXENPRBSTST1[1:0]
RXPRBSERR0
Out
RXPRBSERR1
INTDATAWIDTH
Table 7-19
Table 7-19: PRBS Detection Attributes
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
defines the PRBS detection ports.
Clock
Dir
Domain
Resets the PRBS error counter.
In
RXUSRCLK2
PRBSCNTRESET is applied synchronously and is effective only on its
rising edge.
Receiver test pattern checker control:
00: Disable PRBS checkers
01: Enable 2
In
RXUSRCLK2
10: Enable 2
11: Enable 2
INTDATAWIDTH must also be 1 (10-bit internal data width mode)
when the PRBS checker is enabled.
RXPRBSERR goes High when the number of errors in PRBS testing
RXUSRCLK2
exceeds the value set by the PRBS_ERR_THRESHOLD attribute.
Specifies the width of the internal datapath for the entire GTP_DUAL
In
Async
tile. The PRBS detector is only valid when INTDATAWIDTH = 1 (10-bit
internal datapath).
defines the PRBS detection attributes.
Attribute
PRBS_ERR_THRESHOLD0
PRBS_ERR_THRESHOLD1
www.xilinx.com
Description
7
-1 PRBS checker
23
-1 PRBS checker
31
-1 PRBS checker
Description
Sets the error threshold for the PRBS checker. If PRBS testing is
enabled, a counter counts the number of errors. If the number
of errors exceeds the value of PRBS_ERR_THRESHOLD, the
output RXPRBSERR goes High. This attribute is set as a 32-bit
hex value.
PRBS Detection
147
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