Pcomma_Detect; Mcomma_Detect; Comma_10B_Mask; Pcomma_10B_Value - Xilinx RocketIO User Manual

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PCOMMA_DETECT,

MCOMMA_DETECT

These two control attributes define when RXCOMMADET signals that a comma has been
received. When only PCOMMA_DETECT is TRUE, RXCOMMADET signals when a plus-
comma is received, but not a minus-comma. When only MCOMMA_DET is TRUE,
RXCOMMADET signals when a minus-comma is received, but not a plus-comma. If both
attributes are TRUE, RXCOMMADET will signal when either comma character is received.

COMMA_10B_MASK,

PCOMMA_10B_VALUE,

MCOMMA_10B_VALUE

The RocketIO transceiver allows the user to define a comma character using these three
attributes. The COMMA_10B_MASK bits are used in conjunction with
PCOMMA_10B_VALUE (to define a plus-comma) or MCOMMA_10B_VALUE (to define a
minus-comma) to define some number of recognized comma characters. High bits in the
mask condition the corresponding bits in PCOMMA_10B_VALUE or
MCOMMA_10B_VALUE to matter, while Low bits in the mask function as a "don't care"
conditioner.
For example, with COMMA_10B_MASK set to 1111111000 (meaning the three least
significant bits don't matter) and PCOMMA_10B_VALUE is 0011111000, the comma
detection unit will recognize the following characters as plus-commas:
Using the same value in PCOMMA_10B_VALUE but setting COMMA_10B_MASK to
1111111111 (meaning all the bits in PCOMMA_10B_VALUE matter), the comma
detection unit will recognize only the 0011111000 (K28.7) sequence, which matches the
value of PCOMMA_10B_VALUE exactly.
DEC_PCOMMA_DETECT,
DEC_MCOMMA_DETECT,
DEC_VALID_COMMA_ONLY
These signals only pertain to the 8B/10B decoder, not the comma alignment circuitry. The
DEC_PCOMMA_DETECT and DEC_MCOMMA_DETECT control the 8B/10B decoder to
signal the RXCHARISCOMMA port if a plus-comma or minus-comma is received. This is
described in the table below.
DEC_VALID_COMMA_ONLY, for most applications, should be set to TRUE. If valid data
is being transmitted and hence received, then an invalid comma would arise only in the
case of a bit error, in which case RXCHARISCOMMA would not be asserted in the
presence of bit errors. If set to FALSE, then RXCHARISCOMMA will be asserted for
invalid K-characters.

RXREALIGN

This status signal indicates whenever, the serial data is realigned from a comma character
in the data stream. This signal will not necessarily go High after the transceiver is reset. If
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0011111000 (K28.7)
0011111001 (K28.1)
0011111010 (K28.5)
0011111011 through 0011111111 (not valid comma characters)
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Chapter 2: Digital Design Considerations
RocketIO™ Transceiver User Guide
UG024 (v3.0) February 22, 2007