Xilinx Virtex-5 RocketIO GTP User Manual

Virtex-5 RocketIO GTP Transceiver User Guide www.xilinx.com 99
UG196 (v1.3) May 25, 2007
Configurable 8B/10B Encoder
R
Ports and Attributes
Table 6-4 defines the TX encoder ports.
Table 6-4: TX Encoder Ports
Port Dir Clock Domain Description
TXBYPASS8B10B0[1:0]
TXBYPASS8B10B1[1:0]
In TXUSRCLK2
TXBYPASS8B10BUSE controls the operation of the TX 8B/10B
encoder on a per-byte basis. It is only effective when both
TXENC8B10B and INTDATWIDTH are High (8B/10B is
enabled).
TXBYPASS8B10BUSE[1] corresponds to TXDATA[15:8], and
TXBYPASS8B10BUSE[0] corresponds to TXDATA[7:0].
00: Both bytes are 8B/10B encoded
01: Only TXDATA[15:8] is 8B/10B encoded
10: Only TXDATA[7:0] is 8B/10B encoded
11: Neither byte is 8B/10B encoded
TXCHARDISPMODE0[1:0]
TXCHARDISPMODE1[1:0]
In TXUSRCLK2
TXCHARDISPMODE and TXCHARDISPVAL allow the 8B/10B
disparity of outgoing data to be controlled when 8B/10B
encoding is enabled.
When 8B/10B encoding is disabled, TXCHARDISPMODE is
used to extend the data bus for TX interfaces whose width is a
multiple of 10 (see “FPGA TX Interface,” page 90 for details).
TXCHARDISPMODE[1] corresponds to TXDATA[15:8] and
TXCHARDISPMODE[0] corresponds to TXDATA[7:0].
Table 6-5, page 101 shows how TXCHARDISPMODE is used to
control the disparity of outgoing data when 8B/10B encoding is
enabled.
TXCHARDISPVAL0[1:0]
TXCHARDISPVAL1[1:0]
In TXUSRCLK2
TXCHARDISPVAL and TXCHARDISPMODE allow the
disparity of outgoing data to be controlled when 8B/10B
encoding is enabled.
When 8B/10B encoding is disabled, TXCHARDISPVAL is used
to extend the data bus for 10- and 20-bit TX interfaces (see
“FPGA TX Interface,” page 90 for details).
TXCHARDISPVAL[1] corresponds to TXDATA[15:8]
TXCHARDISPVAL[0] corresponds to TXDATA[7:0]
Table 6-5, page 101 shows how TXCHARDISPVAL is used to
control the disparity of outgoing data when 8B/10B encoding is
enabled.
TXCHARISK0[1:0]
TXCHARISK1{1:0]
In TXUSRCLK2
TXCHARISK is set High to send TXDATA as an 8B/10B
K character. TXCHARISK should only be asserted for TXDATA
values in the K-character table of the 8B/10B table in
Appendix C, “8B/10B Valid Characters.”
TXCHARISK[1] corresponds to TXDATA[15:8], and
TXCHARISK[0] corresponds to TXDATA[7:0].
TXCHARISK is undefined for bytes th
at bypass 8B/10B encoding.

Xilinx Virtex-5 RocketIO GTP Specifications

General

Brand	Xilinx
Model	Virtex-5 RocketIO GTP
Category	Transceiver
Language	English