2–74
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Receiver Modules
7-Bit Pattern Mode
In the 7-bit pattern detection mode (use this mode with 8B/10B code), the
pattern detector matches the seven LSBs of the 10-bit alignment pattern,
which you specified in your ALT2GXB custom megafunction variation, in
the current word boundary. Both positive and negative disparities are
also checked in this mode.
The 7-bit pattern mode can mask out the three MSBs of the data, which
allows the pattern detector to recognize multiple alignment patterns. For
example, in the 8B/10B encoded data, a /K28.5/ (b'0011111010), /K28.1/
(b'0011111001), and /K28.7/ (b'0011111000) share seven common LSBs.
Masking the three MSBs allows the pattern detector to resolve all three
alignment patterns and indicate them on the
rx_patterndetect
port.
In 7-bit pattern mode, the word aligner still aligns to a 10-bit word
boundary. The specified 7-bit pattern forms the least significant seven bits
of the 10-bit word.
10-Bit Pattern Mode
In the 10-bit pattern detection mode (use this mode with 8B/10B code),
the module matches the 10-bit alignment pattern you specified in your
ALT2GXB custom megafunction variation with the data and its
complement in the current word boundary. Both positive and negative
disparities are checked by the pattern checker in this mode. For example,
if you specify a /K28.5/ (b’0011111010) pattern as the comma,
rx_patterndetect
is asserted if b’0011111010 or b’1100000101 is
detected in the incoming data.
16-bit Pattern Mode
You specify the 16-bit alignment pattern in the MegaWizard and it is
oriented with the MSB first and the LSB last. 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 specified in the MegaWizard is detected in this mode.
32
rx_patterndetect[3] rx_dataout[31:24]
rx_patterndetect[2] rx_dataout[23:16]
rx_patterndetect[1]
rx_dataout[15:8]
rx_patterndetect[0] rx_dataout[7:0]
Table 2–20. Corresponding Signals for rx_dataout (Part 2 of 2)
Data Width
Signal
Corresponding Signal