Define internal signal as a base clock?

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I did have a play with TimeQuest yesterday, but what put me off was the need to edit the SDC file by hand...

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Once you have your initial SDC file, you do need to edit it to make changes. (Don't make the mistake some people do of making changes in the TimeQuest GUI and thinking write_sdc will then update their original SDC file with the changes. That's not the correct use of write_sdc.)

You still have GUI assistance for SDC changes. If you use the text editor, use "Edit --> Insert Constraint" to get to dialog boxes that will create the SDC commands and place them in the file. If you are editing a constraint that is already in the file, hover the mouse over the SDC command name to get a tooltip with a list of arguments. If you create constraints in the TimeQuest GUI, then copy them from the Console or History tab of the Console window to your SDC file after you are satisfied with them.