Altera Corporation
2–35
October 2007
Stratix II GX Device Handbook, Volume 2
Stratix II GX Transceiver Architecture Overview
10-Bit Encoding
In single-width mode, the 8B/10B encoder translates the 8-bit data or
8-bit control character (as qualified by the control identifier) to a 10-bit
code group with proper disparity.
Figure 2–27
shows the conversion
format. The LSB is transmitted first.
f
For additional information regarding the 8B/10B code itself, refer to the
Specifications & Additional Information
chapter in volume 2 of the
Stratix II GX Handbook
.
Figure 2–27. 8B/10B Conversion Format
Reset Condition
The
tx_digitalreset
signal resets the 8B/10B encoder. During reset,
the running disparity registers and the data registers are cleared. The
8B/10B encoder outputs a K28.5 pattern from the RD- column
continuously until
tx_digitalreset
goes low. The input data and
tx_ctrlenable
signals are ignored during the reset state. Once out of
reset, the 8B/10B encoder starts with a negative disparity (RD-) and
transmits three K28.5 code groups for synchronizing before it starts
encoding and transmitting the data on the
tx_datain
port.
While the
tx_digitalreset
signal is asserted, the 8B/10B decoder
receives errors in the form of an invalid code error, synchronization error,
control detect, and/or disparity error.
7
6
5
4
3
2
1
0
H
G
F
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D
C
B
A
8B/10B Conversion
7
6
5
4
3
2
1
0
9
8
g
f
i
e
d
c
b
a
j
h
LSB
MSB
CTRL