Ports And Attributes - Xilinx Virtex-5 RocketIO GTP User Manual

R
Figure 7-11
parallel data is on the right side.
The GTP transceiver includes an alignment block that can be programmed to align specific
commas to various byte boundaries, or to manually align data using attribute settings (see
Table 7-21, page
block can be bypassed to reduce latency if it is not needed.

Ports and Attributes

Table 7-20
Table 7-20: RX Comma Alignment and Detection Ports
Port
RXBYTEISALIGNED0
RXBYTEISALIGNED1
RXBYTEREALIGN0
RXBYTEREALIGN1
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
shows the TX parallel data is on the left side, and the RX receiving recognizable
TX Parallel Data
Data0
Comma
Data1
Data2
Figure 7-11: Parallel Data View of Comma Alignment
151). SONET A1A2 alignment is possible using comma double mode. The
defines the RX comma alignment and detection ports.
Clock
Dir
Domain
Signal from comma detection and realignment circuit. Stays High
to indicate that the parallel data stream is properly aligned on byte
boundaries according to comma detection.
0: Parallel data stream not aligned to byte boundaries
1: Parallel data stream aligned to byte boundaries
Out RXUSRCLK2
There will be several cycles after RXBYTEISALIGNED is asserted
before aligned data is available at the FPGA RX interface.
RXBYTEISALIGNED responds to plus comma alignment when
PCOMMA_ALIGN is TRUE. RXBYTEISALIGNED responds to
minus comma alignment when MCOMMA_ALIGN is TRUE.
Signal from comma detection and realignment circuit indicating
that the byte alignment within the serial data stream has changed
due to a comma detection.
0: Byte alignment has not changed
Out RXUSRCLK2
1: Byte alignment has changed
Data can be lost when alignment occurs, which can cause data
errors (and disparity errors when the 8B/10B decoder is used).
www.xilinx.com
Configurable Comma Alignment and Detection
RX Parallel Data
Time
UG96_c7_11_092606
Description
?????
Comma
Data1
Data2
149