Xilinx Constraints Guide

IN_TERM (In Term)
Architecture Support
Applicable Elements
The IN_TERM (In Term) constraint:
• Is a basic mapping constraint.
• Sets a configuration of input termination resistors .
Chapter 4: Xilinx Constraints
In Term is valid on an input pad NET, input pad INST, or for the entire design.
Applies to FPGA devices. Does not apply to CPLD devices.
This constraint may be used with an FPGA device in one or more of the following design
elements, or categories of design elements:
• IOB input components (such as IBUF)
• Input Pad Net
Propagation Rules
Not all devices support all elements. To see which design elements can be used with
which devices, see the Libraries Guides. For more information, see the device data sheet.
IN_TERM is illegal when attached to a net or signal, except when the net or signal is
connected to a pad. In this case, IN_TERM is treated as attached to the pad instance.
Syntax Examples
The following examples show how to use this constraint with particular tools or
methods. If a tool or method is not listed, you cannot use this constraint with it.
Values
• NONE
• TUNED_SPLIT
• UNTUNED_SPLIT_25
• UNTUNED_SPLIT_50
• UNTUNED_SPLIT_75
Schematic Syntax
• Attach to a pad net
• Attribute Name
IN_TERM
• Attribute Values
See Values section above.
Constraints Guide
UG625 (v. 13.2) July 6, 2011 www.xilinx.com 137