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R
TX PRBS Generator
Overview
Pseudo-random bit sequences (PRBS) are commonly used to test the signal integrity of
high-speed links. These sequences appear random but have specific properties that can be
used to measure the quality of a link.
The GTP PRBS block can generate several industry-standard PRBS patterns.
the available PRBS patterns and their typical use.
Table 6-11: Pseudo-Random Bit Sequences
Name
Polynomial
6
7
1 + X
+ X
PRBS-7
(inverted)
18
23
1 + X
+ X
PRBS-23
(inverted)
28
31
1 + X
+ X
PRBS-31
(inverted)
Ports and Attributes
Table 6-12
Table 6-12: TX PRBS Generator Ports
Port
TXENPRBSTST0[1:0]
TXENPRBSTST1[1:0]
INTDATAWIDTH
There are no attributes in this section.
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
Length of
Consecutive
Sequence (bits)
Zeros
7
2
– 1
23
2
– 1
31
2
– 1
defines the TX PRBS generator ports.
Clock
Dir
Domain
Transmitter test pattern generation control. A pseudo-random bit sequence
(PRBS) is generated by enabling the test pattern generation circuit.
INTDATAWIDTH must also be 1 (10-bit internal data width mode) when
the PRBS generator is enabled.
00: Test pattern generation off (standard operation mode)
In
01: Enable 2
10: Enable 2
11: Enable 2
Because PRBS patterns are deterministic, the receiver can check the received
data against a sequence of its own PRBS generator.
Specifies the width of the internal datapath for the entire GTP_DUAL. The
In
Async
PRBS Generator will only work when INTDATAWIDTH = 1 (10-bit internal
datapath)
www.xilinx.com
Used to test channels with 8B/10B.
7
ITU-T Recommendation O.150, Section 5.6. One of the
23
recommended test patterns in the SONET specification.
ITU-T Recommendation O.150, Section 5.8. A
31
recommended PRBS test pattern for 10 Gigabit
Ethernet. See IEEE 802.3ae-2002.
Description
7
– 1 PRBS generation
23
– 1 PRBS generation
31
– 1 PRBS generation
TX PRBS Generator
Table 6-11
Typical Use
lists
109
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