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Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Receiver Modules
detector to resolve all three alignment patterns and indicate it on the
rx_patterndetect
port. If the alignment pattern appears on the
MSByte, no actions are taken by the pattern detect module.
8-Bit Pattern Mode
You can enable a single 8-bit character (A1) detection in the MegaWizard.
In this mode, the pattern detector detects a single 8-bit alignment pattern
character in the LSByte of the data path. If the alignment pattern appears
in the MSByte, no action is taken by the pattern detector.
10-Bit Pattern Mode
In the 10-bit pattern detection mode, the pattern detector matches the
10-bit alignment pattern you specified in the MegaWizard to the LSByte
data and its complement in the current word boundary. The pattern
detector checks both positive and negative disparities in this mode. For
example, if you specified a /K28.5/ (b'0011111010) pattern as the
alignment pattern, the
rx_patterndetect
signal is asserted if
b’0011111010 or b’1100000101 is detected in the incoming data. If the
alignment pattern appears on the MSByte, no action is taken by the
pattern detector.
16-Bit Pattern Mode
You enable the two consecutive 8-bit characters (A1A2).
You specify the 16-bit alignment pattern, which has the bit orientation of
[MSB..LSB]
, in the MegaWizard. A1 represents the least significant
byte, which consists of bits
[7..0]
. A2 represents the most significant
byte, which consists of bits
[15..8]
. Therefore, the alignment pattern is
specified as [A2,A1] in the MegaWizard. Only the actual alignment
pattern you specified in the MegaWizard is detected in this mode.
20-Bit Pattern Mode
In the 20-bit pattern detection mode, the pattern detector matches the
20-bit comma (K1K2) you specified in the MegaWizard to the incoming
data stream. The pattern detector checks the true and complement of the
pattern. For example, if you specify a /K28.5/ and /K28.0/
(10’b0011111010, 10’b0011110100) pattern as the alignment pattern, the
rx_patterndetect
signal is asserted if 10’b0011111010 or
10’b1100000101 and 10’b0011110100 or 10’b1100001011 are detected in the
incoming data. You do not need to enter the correct disparity in the
MegaWizard, because the true and complement of each code group is
checked. In this mode, only Kx.y codes are used as the true and
complement to represent the same code group (but different disparity).
The Dx.y code group does not necessarily use its true and complement to
represent the same code group.
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