UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 4978

14.x Constraints - What resources should be constrained in the User Constraint File (UCF)?

Description

What resources should be constrained in the UCF?

Solution

The following resources must be constrained in the user constraint file (UCF):

  • The internal signal for one or more clocks (PERIOD)
  • I/O speed (OFFSETS)
  • Logic-using multi-cycle clocks (FROM-TO)
  • Pin-to-pin timing (FROM PADS TO PADS)
  • Pin locations and logic locations (LOC)
  • DCM attributes (DCM...)
  • Initial values of the RAM/ROMs (INIT)

For additional information, see the Xilinx Support Web site:
http://www.xilinx.com/support

For more details on timing constraints, please see the Timing Constraints User Guide:
http://www.xilinx.com/support/documentation/sw_manuals/xilinx14_1/ug612.pdf

AR# 4978
Date Created 08/21/2007
Last Updated 12/15/2012
Status Active
Type General Article
Devices
  • 4000/E/XL/XV
  • 4000E/EX/XL QPro/R
  • 9500
  • More
  • 9500XL
  • 9500XL IQ
  • 9500XL XA
  • 9500XV
  • CoolRunner XPLA3
  • CoolRunner-II
  • CoolRunner-II XA
  • Spartan/XL
  • Spartan-3
  • Spartan-3 XA
  • Spartan-3A
  • Spartan-3A DSP
  • Spartan-3AN
  • Spartan-3E
  • Spartan-6 LX
  • Spartan-6 LXT
  • Spartan-II
  • Spartan-IIE
  • Spartan-IIE XA
  • Spartan-XL IQ
  • Virtex
  • Virtex QPro/R
  • Virtex-4 FX
  • Virtex-4 LX
  • Virtex-4 QPro/R
  • Virtex-4 SX
  • Virtex-5 FXT
  • Virtex-5 LX
  • Virtex-5 LXT
  • Virtex-5 SXT
  • Virtex-5 TXT
  • Virtex-5Q
  • Virtex-6 CXT
  • Virtex-6 HXT
  • Virtex-6 LX
  • Virtex-6 LXT
  • Virtex-6 SXT
  • Virtex-E
  • Virtex-E QPro
  • Virtex-EM
  • Virtex-II
  • Virtex-II Pro
  • Virtex-II Pro X
  • Virtex-II QPro/R
  • Less
Tools
  • ISE - 10.1
  • ISE Design Suite - 11.1
  • ISE Design Suite - 11.2
  • More
  • ISE Design Suite - 11.3
  • ISE Design Suite - 11.4
  • ISE Design Suite - 11.5
  • ISE Design Suite - 12.1
  • ISE - 8.1i
  • ISE - 8.1i sp1
  • ISE - 8.1i sp2
  • ISE - 8.1i sp3
  • ISE - 8.2i
  • ISE - 8.2i sp1
  • ISE - 8.2i sp2
  • ISE - 8.2i sp3
  • ISE - 9.1i
  • ISE - 9.1i sp1
  • ISE - 9.1i sp2
  • ISE - 9.1i sp3
  • ISE - 9.2i
  • ISE - 9.2i sp1
  • ISE - 9.2i sp2
  • ISE - 9.2i sp3
  • ISE - 9.2i sp4
  • ISE - Legacy
  • ISE Design Suite - 12.2
  • ISE Design Suite - 12.3
  • ISE Design Suite - 12.4
  • ISE Design Suite - 13
  • ISE Design Suite - 13.1
  • ISE Design Suite - 13.2
  • ISE Design Suite - 13.3
  • ISE Design Suite - 13.4
  • ISE Design Suite - 14.1
  • Less