AR# 33113

描述

When doing timing analysis using auto generated timing constraints (trce -a option), the clock to out value is different from when doing timing analysis by user specified endpoints (FF to pad). 

Why does this happen?

解决方案

This is an expected behavior. 

This is because when running analysis using user specified endpoints, clock uncertainty is not included in the calculation as the period constraints are not involved.

The difference in the clock to out values comes from the clock uncertainty.