GX3146 Datasheet, PDF (28/46 Pages) Semtech Corporation – Crosspoint Switch with Trace Equalization and Output De-emphasis

Table 4-9: Compared Words
RX0_PRBS_BER_TIME[3:0] (binary)
Number of words* compared (decimal)
0000
Infinite
0001
13
0010
26
0011
3277
0100
6554
0101
838861
0110
1677722
*Note: Each word is comprised of 10 bits, therefore the actual number of samples compared is
10 times the number of words compared.
The status of the two pattern checking blocks is available in the RX0_PRBS_LOCK and
RX1_PRBS_LOCK, RX0_PRBS_PASS and RX1_PRBS_PASS, RX0_PRBS_FAIL and
RX1_PRBS_FAIL, and RX0_PRBS_ERROR_COUNT and RX1_PRBS_ERROR_COUNT
read-only bits (see register addresses 0x81Eh to 0x821h).
• RX0_PRBS_LOCK [0] - When HIGH, indicates that the pattern checker has
acquired the pattern
• RX0_PRBS_PASS [1] - When HIGH, indicates that the pattern was locked, and the
specified number of words have been compared with fewer detected errors than
specified by the RX0_PRBS_BER_THRESH parameter
• RX0_PRBS_FAIL [2] - Indicates that the test terminated in a failure condition.
There are three possible failure conditions:
1. The pattern generator failed to lock in the number of attempts specified by
RX0_PRBS_LOCK_ATTEMPTS (in which case RX0_PRBS_LOCK would still be
'0').
2. The pattern generator locked, but over the period of time indicated by the
RX0_PRBS_LOL_TIME bits, a greater number of errors were detected than
allowed by the RX0_PRBS_LOL_THRESH setting. In this error condition, the
device determines that it has “lost lock“, and terminates the test. This error
condition is detectable if both RX0_PRBS_LOCK and RX0_PRBS_FAIL bits are
HIGH, and the value of RX0_PRBS_ERROR_COUNT is less than
RX0_PRBS_BER_THRESH (the same applies for RX1_PRBS_LOCK,
RX1_PRBS_FAIL and RX1_PRBS_ERROR_COUNT).
3. The pattern generator locked, but the number of errors observed exceeded the
value indicated by the RX0_PRBS_BER_THRESH bits. This error is detectable if
RX0_PRBS_LOCK and RX0_PRBS_FAIL are both HIGH, and the value of
RX0_PRBS_ERROR_COUNT is equal or greater than the value in
RX0_PRBS_BER_THRESH.
GX3146 146 x 146 3.5Gb/s Crosspoint
Final Data Sheet Rev. 2
GENDOC-056075 March 2013
www.semtech.com
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