Altera Stratix GX Transceiver - Manual (Page 58)

3–12 Altera Corporation
Stratix GX Transceiver User Guide January 2005
Basic Mode Receiver Architecture
Figure 3–9. Disparity Error
Control Detect
The 8B/10B can differentiate between data and control codes via the
rx_ctrldetect
port. This port is optional, and if it is not in use, there
is no way of differentiating a Dx.y from a Kx.y.
Figure 3–10 shows an example waveform demonstrating the receipt of a
K28.5 code (BC + ctrl). The rx_ctrldetect=1'b1 is aligned with 8'hbc,
indicating that it is a control code.
Figure 3–10. Control Code Detection
clock
rx_out[7:0 ]
rx_disperr
BC BC BC BC BC BC
rx_ctrldetect
BC
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
xx
clock
rx_out[7:0]
rx_ctrldetect
83 78 BC BC 0F 00 BF 3C
D3.4 D24.3 D28.5 K28.5 D15.0 D0.0 D31.5 D28.1 Code Group