Five-Minute Tutorial: Find A Pin's Transition Time

How many times while working in Encounter Digital Implementation system have you wanted to find the transition time on a certain pin? How did you go about finding it? Here are some ways I know that I've used:

• If I knew the pin was failing the max_transition constraint, hunt it down in the .tran violation report.
• Try to find the pin somewhere in my timing reports and look at the slew column.
• Use (gasp!) undocumented commands (unsupported and therefore sometimes unreliable).

Well, there's an easier, cleaner, faster way. The report_constraint command! This is an oft-forgotten little gem that can be very handy. It's worth reading about all of its features in the documentation, but today I wanted to highlight how it can be used to find the transition violation of any pin. Just specify the constraint we want to report (max transition) and the pin:

report_constraint -drv_violation_type max_transition i_BUFX2/Z

And you'll see results something like this:

I bet some of you out there are using this very command for other useful checks -- share your favorites with us in the comments, please!

- Kari Summers