BeginnerQuestion 4 of 40Source PDF page 8

What are startpoints and endpoints of a timing path?

From PDVerse STA Mentor Guide · pdVerse Mentor Guide

Short Answer

Startpoints are where a path begins — input ports and clock pins of sequential elements; endpoints are where it ends — output ports and the data-input pins of sequential elements.

Example

A path might start at the clock pin (CK) of a launch flip-flop and end at the data pin (D) of a capture flip-flop, or it might start at a chip input port and end at a flip-flop's D pin.

Why It Matters

STA tools need clearly defined start and end points to know exactly where to begin summing delay and where to check it against a required time — this pairing is what defines each individual path to be analyzed.

Mentor Note — Common Mistake

Confusing a flip-flop's D pin with a startpoint — the D pin is where data goes in, making it an endpoint, while the CK pin (where the clock edge triggers a new launch) is the startpoint.

Visual explanationSTA context: What are startpoints and endpoints of a timing path?
STA context: What are startpoints and endpoints of a timing path?A three-step concept map summarizes the focus, core answer, and practical verification for What are startpoints and endpoints of a timing path?Question focusWhat are startpoints andendpoints of a timingpath?Core answerStartpoints are where apath begins — inputports and clock pins…Verify in practiceConfirm the path,constraints, clockassumptions, and timingreport.Understand → explain the mechanism → verify the assumptions

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