Answers Database
M1.5/2.1i: Constraint Editor : unable to find clock signal in global tab
Record #6130
Product Family: Software
Product Line: M1 Implementation
Product Part: Constraints Editor
Product Version: 1.5is2
Problem Title:
M1.5/2.1i: Constraint Editor : unable to find clock signal in global tab
Problem Description:
Urgency: Standard
The constaint editor may not find all clock signals in a design.
In general, the constraint editor finds clock nets and traces
them back to their source. At the source it is named and
available for period constraints. Net names along the path
of that clock path will show up aside from the source signal
name. Derived clocks in particular will not show up. A clock
signal which is derived from multiple other clock signals through
a mux or other such function will not show up. Even with a
bufg applied to that signal it will not show up.
Solution 1:
Using the UCF file any clock net can be named and a period
constraint can be added. This is limitation to the Constraint
Editor, not to the constraint itself. It is possible to add a
clock signal not available in the constraint editor into the
ucf file manually and apply the constraint. For detials on
adding period constraints: refer to the software manuals
available on support.xilinx.com.
End of Record #6130 - Last Modified: 07/13/99 08:40 |
