Reset, Code error detect – Altera Stratix GX Transceiver User Manual
Page 56
3–10
Altera Corporation
Stratix GX Transceiver User Guide
January 2005
Basic Mode Receiver Architecture
Figure 3–8. 10-Bit to 8-Bit Conversion
Reset
The rxdigitalreset signal governs the reset condition of the 8B/10B
decoder. In reset, the disparity registers are cleared. Upon exiting reset,
the 8B/10B decoder can start with either a positive or negative disparity.
The decoder calculates the initial running disparity based on the first
valid code received.
The receiver block must be word aligned after reset before the 8B/10B
decoder can decode valid data or control codes.
Code Error Detect
The rx_errdetect signal indicates when the code that is received
contains an error. This port is optional and if not in use, there is no way to
determine whether a code that is received is valid. The rx_errdetect
signal goes high if a code received is an invalid code or if it contains a
disparity error. If a code is received that is not part of the valid Dx.y or
Kx.y list, the rx_errdetect signal goes high. This signal is aligned with
the invalid code word that is received at the device logic array and/or the
code word that triggered the disparity error.
7
6
5
4
3
2
1
0
H
G
F
E
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 received
first
MSB received
last
Parallel Data + CTRL