SmartTime Static Timing Analyzer User Guide
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Figure 68 · Analyzing the false paths
Similar analysis shows that the path from D0_inv_reg:CLK to Q_reg:D shares exactly the same false-path
characteristic. We should disable both paths.
5. Re-start the Libero Constraints Editor. The Constraints Editor must be running in order for us to use
the back-annotation feature of StartTime. Go to the Constraint Manager tab, Timing sub-tab; and again
pull down the "Edit with Constraint Editor" , and choose "Edit Timing Verification Constraints".
6. Leave this running and go back to SmartTime. From the
Tools
menu select
Max Delay Analysis
.
7. To set the path from D0_inv_reg:CLK to Q_reg :D as false, select the row containing this path in the
Register to Register path set, right-click and choose
Add False Path Constraint
(as shown in the
figure below). The Set False Path Constraint dialog box appears (it may pop-behind; check other
Constraint Manager windows).
Figure 69 · Right-Click > Add False Path Constraint
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