Pcomma_Detect; Mcomma_Detect; Comma_10B_Mask, Pcomma_10B_Value, Mcomma_10B_Value; Dec_Mcomma_Detect Dec_Valid_Comma_Only - Xilinx RocketIO User Manual

SERDES Alignment

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
ENPCOMMAALIGN and ENMCOMMAALIGN are both set to zero then this signal should not go
High. See
RocketIO™ Transceiver User Guide
UG024 (v2.3.2) June 24, 2004
0011111000 (K28.7)
0011111001 (K28.1)
0011111010 (K28.5)
0011111011 through 0011111111 (not valid comma characters)
Table 2-13.
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