Comma Detection; Summary; Bypass; Symbol Detection - Xilinx RocketIO X User Manual

Block Level Functions

Comma Detection

Summary

Comma detection has been expanded beyond 10-bit symbol detection and alignment to
include 8-bit symbol detection and alignment for 16-, 20-, 32-, and 40-bit paths. The ability
to detect symbols, and then either align to 1-word, 2-word, or 4-word boundaries is
included. The RXSLIDE input allows the user to "slide" or "slip" the alignment by one bit
in each 16-, 20-, 32- and 40-bit mode at any time for SONET applications.
The following signals/attributes affect the function of the comma detection block:
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Bypass

By deasserting RXCOMMADETUSE Low, symbol detection is not enabled. If
RXCOMMADETUSE is asserted High, symbol detection takes place.

Symbol Detection

By using the signals MCOMMA_10B_VALUE, DEC_MCOMMA_DETECT,
PCOMMA_10B_VALUE, DEC_PCOMMA_DETECT, and COMMA_10B_MASK any 8-bit
or 10-bit symbol detection can take place for two different symbol values.
To detect a 10-bit symbol COMMA_10B_MASK[9:0] should initially be set to
10'b11111_11111. Any bit can be changed to further affect the masking capability.
To detect an 8-bit symbol, the COMMA_10B_MASK[9:0] should be set to 10'b00_1111_1111.
The first two bits must be set to zero. Any of the last 8 bits can be altered to change the
mask further.
The MCOMMA_10B_VALUE[9:0] and PCOMMA_10B_VALUE[9:0] fields indicate the
comma symbol definitions to be used by the comparison logic, i.e., the templates against
which incoming data is compared in the search for commas to establish alignment.
The DEC_MCOMMA_DETECT and DEC_PCOMMA_DETECT indicate which symbol
should be compared to the incoming data for alignment. See
RocketIO™ X Transceiver User Guide
UG035 (v1.5) November 22, 2004
RXCOMMADETUSE
ENMCOMMAALIGN
ENPCOMMAALIGN
ALIGN_COMMA_WORD[1:0]
MCOMMA_10B_VALUE[9:0]
DEC_MCOMMA_DETECT
PCOMMA_10B_VALUE[9:0]
DEC_PCOMMA_DETECT
COMMA_10B_MASK[9:0]
RXSLIDE
RXINTDATAWIDTH[1:0]
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Table 2-8.
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