Manual Alignment - Xilinx Virtex-5 RocketIO GTP User Manual

Chapter 7: GTP Receiver (RX)

Manual Alignment

RXSLIDE can be used to override the automatic comma alignment and to shift the parallel
data. RXSLIDE is driven High for one RXUSRCLK2 cycle to shift the parallel data to the left
by one bit. RXSLIDE must be Low for at least two RXUSRCLK2 cycles before it can be used
again.
Figure 7-16
the data shift.
RXUSRCLK2
RXSLIDE
RXDATA
0000010000
TXDATA
Notes:
1. Latency between the slide and the slide result at RXDATA depends on the number of active RX PCS blocks in the datapath.
154
RXDATAWIDTH
0 (1-byte)
0 (1-byte)
1 (2-byte)
1 (2-byte)
Figure 7-15: Comma Alignment Boundaries
shows the waveforms for manual alignment using RXSLIDE, before and after
. . .
. . . . . .
. . .
Figure 7-16: Manual Data Alignment Using RXSLIDE
www.xilinx.com
ALIGN_COMMA_WORD
1 (Any Boundary)
2 (Even Boundary Only)
1 (Any Boundary)
2 (Even Boundaries Only)
Slide Results on RXDATA
After Several Cycles of Latency
0000100000
0000010000
Virtex-5 RocketIO GTP Transceiver User Guide
Possible RX Alignments
(Grey = Comma Can Appear
on Byte)
RXDATA Byte 0
Invalid Configuration
RXDATA Byte 1 RXDATA Byte 0
RXDATA Byte 1 RXDATA Byte 0
UG196_c7_15_092606
. . .
. . . . . .
0001000000
. . .
UG196_c7_16_092606
UG196 (v1.3) May 25, 2007
R