What checks are needed when applying useful skew and how to apply limit?

Q: "What checks are needed when applying useful skew and how to apply limit?"

"o Setting Limits: setUsefulSkewMode -maxAllowedDelay \u0026lt;Value\u0026gt;\nChecks Needed When Applying Useful Skew: when usefulSkew is enabled in preCTS and at CTS, tool does all the checks before applying for the skew. At ECO if doing manual adjustment, below things to be checked:\nHold Time on the Same Path: The most critical check. Timing to Launch Flop: Check setup and hold timing for paths ending at the launch flop. If skew is borrowed from this path, it may get setup violation. Timing from Capture …"

o Setting Limits: setUsefulSkewMode -maxAllowedDelay <Value>

Checks Needed When Applying Useful Skew: when usefulSkew is enabled in preCTS and at CTS, tool does all the checks before applying for the skew. At ECO if doing manual adjustment, below things to be checked:

Hold Time on the Same Path: The most critical check.
Timing to Launch Flop: Check setup and hold timing for paths ending at the launch flop. If skew is borrowed from this path, it may get setup violation.
Timing from Capture Flop: Check setup and hold timing for paths starting from the capture flop. If skew borrowed from this path, it may get setup vio.
Overall QOR: After applying useful skew (usually as part of an optimization run or ECO), re-run full STA to ensure no new violations have been created
CPPR Impact: Pushing Capture or pulling Launch flop to add skew, may change your CPPR and contribute to timing violations.

All Questions

We value your privacy

Manage Cookie Preferences