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Chapter 7: Custom PHY IP Core
Parameter Settings
Altera Transceiver PHY IP Core
March 2012
Altera Corporation
User Guide
Word Alignment
The word aligner restores word boundaries of received data based on a predefined
alignment pattern. This pattern can be 7, 8, 10, 16, 20, or 32 bits long. The word
alignment module searches for a programmed pattern to identify the correct
boundary for the incoming stream.
Table 7–5
lists the settings available on the
Word
Aligner
tab.
Table 7–5. Word Aligner Options
Name
Value
Description
Wo
r
d alignmen
t
mode
Manual
You can select 1 of the following 3 modes:
■
Manual
–In this mode you enable the word alignment function by
asserting
rx_enapatternalign
using the Avalon-MM interface.
When the PCS exits reset, the word aligner automatically performs
an initial alignment to the specified word alignment pattern. After
the initial alignment, you must assert
rx_enapatternalign
to
initiate another pattern alignment.
rx_enapatternalign
is edge
sensitive.
Bi
t
slipping
■
Bi
t
slipping
–You can use bit slip mode to shift the word boundary
using the Avalon-MM interface. For every rising edge of the
rx_bitslip
signal, the word boundary is shifted by 1 bit. Each bit
slip removes the earliest received bit from the received data.
Au
t
oma
t
ic
synch
r
oniza
t
ion
s
t
a
t
e machine
■
Au
t
oma
t
ic synch
r
oniza
t
ion s
t
a
t
e machine
–In this mode, word
alignment is controlled by a programmable state machine. This
mode can only be used with 8B/10B encoding. The data width at
the word aligner can be 10 or 20 bits. You can specify the following
parameters:
■
Numbe
r
of consecu
t
ive valid wo
r
ds befo
r
e sync s
t
a
t
e is
r
eached:
Specifies the number of consecutive valid words
needed to reduce the built up error count by 1. Valid values are
1–256.
■
Numbe
r
of bad da
t
a wo
r
ds befo
r
e loss of sync s
t
a
t
e:
Specifies
the number of bad data words required for alignment state
machine to enter loss of sync state. Valid values are 1–256.
■
Numbe
r
of valid pa
tt
e
r
ns befo
r
e sync s
t
a
t
e is
r
eached:
Specifies the number of consecutive patterns required to
achieve synchronization. Valid values are 1–256.
■
C
r
ea
t
e op
t
ional wo
r
d aligne
r
s
t
a
t
us po
rt
s
: When enabled the
rx_syncstatus
and
rx_patterndetect
status ports are
created.
■
Wo
r
d alignmen
t
pa
tt
e
r
n leng
t
h:
Allows you to specify a 7- or
10-bit pattern for use in the word alignment state machine.
■
Wo
r
d alignmen
t
pa
tt
e
r
n:
Allows you to specify a word
alignment pattern.
Enable
r
un leng
t
h viola
t
ion
checking
On/Off
If you turn this option on, you can specify the run length which is the
maximum legal number of contiguous 0s or 1s.
Run leng
t
h
40–640
Specifies the threshold for a run-length violation.