2–214
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Reset Control and Power Down
Table 2–51
shows the BIST patterns for double-width mode.
PRBS7
Pseudo-Random Bit Sequences (PRBS) are commonly used in systems to
verify the integrity and robustness of the data transmission paths. The
PRBS7 generator generates 2^7-1 unique patterns. PRBS can be used with
or without serial loopback. In PRBS/ serial loopback mode, the
rx_seriallpbken
signal is available. In the PRBS/no loopback mode,
this control signal is not available.
You enable PRBS mode in the MegaWizard. PRBS7 does not use the
8B/10B encoder and decoder. The 8B/10B encoder and decoder are
bypassed automatically in the PRBS mode.
The advantage of using a PRBS data stream is that the randomness yields
an environment that stresses the transmission medium. In the data stream
you can observe both random jitter and deterministic jitter using a time
interval analyzer, bit error rate tester, or oscilloscope.
The PRBS verifier provides a quick check through the non-8B/10B path
of the transceiver block. The PRBS verifier is active once the receiver
channel is synchronized. Set the alignment pattern to 20'h43040 for the 20-
bit SERDES modes. The PRBS verifier prevents the word aligner from
aligning to a new pattern after the first five successfully verified words.
The verifier stops checking the patterns after receiving all the PRBS
patterns (127 patterns for PRBS7). The
rx_bistdone
signal goes high,
indicating that the verifier has completed. If the verifier detects an error
before it is finished,
rx_bisterr
pulses high for as long as the data is in
error. Use the
rx_digitalreset
signal to re-start the PRBS verification.
Reset Control
and Power Down
Stratix II GX transceivers offer multiple reset signals to control separate
ports of the transceiver channels and blocks (
Figure 2–159
). You can set
each unused channel to a power-down mode to reduce power
consumption.
Table 2–51. Available BIST Patterns in Double-Width Mode
PATTERN
Word Aligner
Alignment
Pattern
Byte Order Align
Pattern
Description
Double-Width Mode
16 Bit
20 Bit
PRBS7
20'h43040
N/A
X
7
+ X
6
+ 1
v