Altera Stratix GX Transceiver - Manual (Page 126)

5–14 Altera Corporation
Stratix GX Transceiver User Guide January 2005
XAUI Mode Receiver Architecture
Figure 5–10. Disparity Error
Control Detect
The 8B/10B has the ability to differentiate between data and control codes
via the rx_ctrldetect port. If this port is not in use, there is no way to
differentiate Dx.y from Kx.y.
Figure 5–11 shows an example waveform demonstrating the detection of
a K28.5 code (BC + ctrl). The rx_ctrldetect=1'b1 is aligned with
8'hbc
, which indicates that this code is a control code. The reset of the
code received is data.
Figure 5–11. Control Code Detection
clock
rx_out[7:0 ]
rx_disperr
07 07 07 07 07 07
rx_ctrldetect
07
Expected RD code
rx_in 17C 283 17C 283 283 283 17C 17C
RD- RD+ RD+ RD- RD- RD- RD+ RD-
RD code received RD- RD+ RD+ RD- RD+ RD- RD+ RD-
n n+1 n+2 n+3 n+4 n+5 n+6 n+7
rx_errdetect
FE
clock
rx_out[7:0]
rx_ctrldetect
83 78 BC 07 0F 00 BF 3C
D3.4 D24.3 D28.5 K28.5 D15.0 D0.0 D31.5 D28.1 Code Group