2–90
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Receiver Modules
the alignment pattern has been detected on the LSByte of the current
word boundary. If the pattern exists on the MSByte, the
rx_syncstatus
signal goes high.
Figure 2–68. Word Aligner Symbols Interacting in 10-Bit Manual Alignment Mode
Manual 16-Bit Alignment Mode
You can enable the 16-bit alignment mode in the double-width mode.
This mode aligns to the 16-bit alignment pattern you specified in the
MegaWizard.
The byte boundary is locked after the pattern detector detects the first
alignment pattern and then after the rising edge of the
rx_enapatternalign
port. If the byte boundary changes, the
rx_enapatternalign
port must be deasserted and reasserted to
enable the alignment circuit to search for and align to the next available
alignment pattern. On the rising edge of the
rx_enapatternalign
signal, the word aligner locks onto the first alignment pattern detected. In
this scenario the
rx_patterndetect
signal is asserted to signify that
the alignment pattern has been aligned. The
rx_syncstatus
signal is
also asserted to signify that the word boundary has been synchronized.
Manual 20-bit Alignment Mode
In the 20-bit alignment mode, the pattern detector looks for the 20-bit
alignment pattern (K1K2) you specified in the MegaWizard in the
incoming data stream. The pattern detector checks the true and
complement of the pattern. For example, if you specified a /K28.5/ and
/K28.0/ (10'b0011111010, 10'b0011110100) pattern as the alignment
pattern, the byte boundary is set to the pattern boundary when
10'b0011111010 or 10'b1100000101 and 10'b0011110100 or 10'b1100001011
are detected in the incoming data. It is not necessary to enter the correct
disparity in the MegaWizard because the true and complement of each
code group is checked automatically by the pattern detector. Do not use
Dx.y codes as the alignment pattern in the 20-bit alignment mode.
rx_clkout
rx_enapatternalign
rx_patterndetect
rx_syncstatus
rx_datain[15..0]
111110000
0101111100
111110000
111110000
1000000101
0101111100
1111001010
n
n + 1
n + 2
n + 3
0101010101
Содержание Stratix II GX
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