
Altera Corporation
2–27
October 2007
Stratix II GX Device Handbook, Volume 1
Stratix II GX Architecture
Figure 2–21. 8B/10B Decoder
The 8B/10B decoder in single-width mode translates the 10-bit encoded
data into the 8-bit equivalent data or control code. The 10-bit code
received must be from the supported Dx.y or Kx.y list with the proper
disparity or error flags asserted. All 8B/10B control signals, such as
disparity error or control detect, are pipelined with the data and
edge-aligned with the data.
Figure 2–22 shows how the 10-bit symbol is
decoded in the 8-bit data + 1-bit control indicator.
Figure 2–22. 8B/10B Decoder Conversion
The 8B/10B decoder in double-width mode translates the 20-bit
(2 × 10-bits) encoded code into the 16-bit (2 × 8-bits) equivalent data or
control code. The 20-bit upper and lower symbols received must be from
the supported Dx.y or Kx.y list with the proper disparity or error flags
8B/10B
Decoder
MSByte
datain[19..10]
To Byte
Deserializer
dataout[15..8]
Status Signals[1] (1)
8B/10B
Decoder
LSByte
datain[9..0]
dataout[7..0]
Status Signals[0]
From Rate
Matcher
(1)
98
76
5
4
3
2
1
0
8B/10B conversion
jh
g
f
i
e
d
c
b
a
MSB received last
LSB received first
76
5
4
3
2
1
0
HG
F
E
D
C
B
A
+
ctrl
Parallel data