Xilinx virtex-5 fpga User Manual

218 www.xilinx.com Virtex-5 FPGA User Guide
UG190 (v5.0) June 19, 2009
Chapter 6: SelectIO Resources
SelectIO Resources Introduction
All Virtex-5 FPGAs have configurable high-performance SelectIO™ drivers and receivers,
supporting a wide variety of standard interfaces. The robust feature set includes
programmable control of output strength and slew rate, and on-chip termination using
Digitally Controlled Impedance (DCI).
Each IOB contains both input, output, and 3-state SelectIO drivers. These drivers can be
configured to various I/O standards. Differential I/O uses the two IOBs grouped together
in one tile.
• Single-ended I/O standards (LVCMOS, LVTTL, HSTL, SSTL, GTL, PCI)
• Differential I/O standards (LVDS, HT, LVPECL, BLVDS, Differential HSTL and SSTL)
• Differential and V
REF
dependent inputs are powered by V
CCAUX
Each Virtex-5 FPGA I/O tile contains two IOBs, and also two ILOGIC blocks and two
OLOGIC blocks, as described in Chapter 7, “SelectIO Logic Resources.”
Figure 6-2 shows the basic IOB and its connections to the internal logic and the device Pad.
Each IOB has a direct connection to an ILOGIC/OLOGIC pair containing the input and
output logic resources for data and 3-state control for the IOB. Both ILOGIC and OLOGIC
can be configured as ISERDES and OSERDES, respectively, as described in Chapter 8,
“Advanced SelectIO Logic Resources.”
SelectIO Resources General Guidelines
This section summarizes the general guidelines to be considered when designing with the
SelectIO resources in Virtex-5 FPGAs.
Virtex-5 FPGA I/O Bank Rules
In Virtex-5 devices, with some exceptions in the center column, an I/O bank consists of 40
IOBs (20 CLBs high and a single clock region). There are always four half-sized banks
(20 IOBs) and a single configuration bank in the center column. The number of banks
X-Ref Target - Figure 6-2
Figure 6-2: Basic IOB Diagram
ug190_6_02_021306
PADOUT
DIFFO_IN
DIFFO_OUT
I
T
O
DIFFI_IN
OUTBUF
INBUF
PA D

Xilinx virtex-5 fpga Specifications

General

Brand	Xilinx
Model	virtex-5 fpga
Category	Computer Hardware
Language	English