Xilinx Virtex-5 RocketIO GTP User Manual

Virtex-5 RocketIO GTP Transceiver User Guide www.xilinx.com 263
UG196 (v1.3) May 25, 2007
Other Minor Differences
R
Other Minor Differences
Te r m i na t io n
In Virtex-II Pro devices, the transceivers contain on-chip termination and reference
voltages for VTTX and VTRX. In Virtex-4 devices, the MGTs use a reference resistor to
create the termination circuitry for each MGT column. The Virtex-5 GTP transceiver
simplifies the termination circuitry by providing a calibrated 50Ω termination. Table A-8
shows the termination options for each FPGA generation.
CRC
CRC support has changed over the generations of transceivers. Table A-9 shows the CRC
support provided by all four transceiver families.
Loopback
The loopback options of the Virtex transceivers have evolved to improve flexibility.
Virtex-II Pro MGTs have two loopback modes, and Virtex-4 MGTs have four loopback
modes. Table A-10 shows this evolution.
Tab le A - 8 : Termination Options
Termination Virtex-II Pro MGT Virtex-4 MGT
Virtex-5 GTP
Transceiver
Value 50/75 Ω 50Ω 50Ω
Voltage Pins VTTX/VTRX VTTX/VTRX MGTAVTTTX/MGTAVTTRX
Tab le A - 9 : CRC Transceiver Support
Virtex-II Pro
MGT
Virtex-4
MGT
Virtex-5
GTP Transceiver
CRC-32 Independent CRC-32
block supports datapath
from 8 to 64 bits wide.
Independent CRC block supports two CRC-32
calculations over 32-bit datapaths or a single
CRC-32 calculation over a 64-bit datapath.
Tab le A - 1 0 : Loopback Options
Mode
Virtex-II Pro
MGT
Virtex-4
MGT
Virtex-5 GTP
Transceiver
Parallel Loopback (Tx → RX) Yes Yes Yes
Serial Pre-Driver – Yes Yes
Serial Post-Driver Yes – –
Serial Digital Receiver – Yes –
External Data PMA-Only Parallel
Loopback
––Yes
PCI Express Repeater – – Yes

Xilinx Virtex-5 RocketIO GTP Specifications

General

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