Hello all, I understand that I can assign timing constraints using a .ucf file. I tried defining one (using the wizard) and including it in the project. In synthesis properties it is not possible to point out a .ucf file, and a .xcf file is expected. I left this blank. I selected the option 'write timing constraints file' and run the synthesis process. I see the tool consulting the .ucf file and gives no warnings. I ran Implement design processes and have a information that all of the timing constraints are met. When I run the simulation using ModelSim, .sdf and .vhd file generated by the ISE tool, the results look like the timing constraints are not met (even if I select a frequency much smaller than the tool accepted). Hints? Thanks in advance, Marija
how to use a .ucf file?
Apr 07, 2004
1 Replies
ngdbuild should automatically pick up a ucf file if it is included in the project. You can also try adding "-uc ucf_file_name" to the ngdbuild command line.
I'd double check the clock frequency on the waveform. You clock generation code may assume a time unit and only use a number as the period. This may not work if the timing simulation uses a different time unit than the one used in the functional simulation.
HTH, Jim snipped-for-privacy@yahoo.com
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