Why do I see Component Switching Limit warnings in my 11.1 PAR report?
-In 10.1, my design had the following warnings:
WARNING:Timing:3238 - Timing Constraint
"TS_clk = PERIOD TIMEGRP "clk" 1 ns HIGH 50%;"
fails the pulse width check for clock "reset_IBUF" because the low value (500 ps) or high value (500 ps) is less
than the minimum internal pulse width limits of 527 ps low and 527 ps high on pin
"/top/PACKED/top/Tracking_Module/Tracking_Module\/address<3>/Tracking_Module\/address_0/SR". Please increase the
period of the constraint to remove this timing failure.
-Now, in 11.1, my design has the following:
WARNING:Par:450 - At least one timing constraint is impossible to meet because component switching limit violations have
been detected for a constrained component. A timing constraint summary below shows the failing constraints (preceded
with an Asterisk (*)). Please use the Timing Analyzer (GUI) or TRCE (command line) with the Mapped NCD and PCF files
to evaluate the component switching limit violations in more detail. Evaluate the data sheet for alternative
configurations for the component that could allow the frequencies requested in the constraint. Otherwise, the timing
constraint covering this component might need to be modified to satisfy the component switching limits specified in
the data sheet.
INFO:Timing:3284 - This timing report was generated using estimated delay
information. For accurate numbers, please refer to the post Place and Route
timing report.
Asterisk (*) preceding a constraint indicates it was not met.
This may be due to a setup or hold violation.
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Constraint | Check | Worst Case | Best Case | Timing | Timing
| | Slack | Achievable | Errors | Score
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* TS_clk = PERIOD TIMEGRP "clk" 1 ns HIGH 5 | SETUP | -1.782ns| 2.782ns| 147| 59989
0% | HOLD | 0.291ns| | 0| 0
| MINPERIOD | -0.818ns| 1.818ns| 2| 1636
| MINLOWPULSE | -0.054ns| 1.054ns| 11| 594
| MINHIGHPULSE| -0.054ns| 1.054ns| 11| 594
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OFFSET = OUT 15 ns AFTER COMP "clk" | MAXDELAY | 6.891ns| 8.109ns| 0| 0
------------------------------------------------------------------------------------------------------
OFFSET = IN 10 ns BEFORE COMP "clk" | SETUP | 7.823ns| 2.177ns| 0| 0
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