Timing Path Types
STA analyzes 4 fundamental path types in digital circuits. Every timing path has a startpoint (port or FF clock pin) and endpoint (FF data pin or output port).
What Is a Timing Path? — A timing path is the route a signal takes through combinational logic from where it starts (a startpoint) to where it's captured (an endpoint). Startpoint = either a flip-flop's clock pin (Q output launches data) or an input port (external data enters the chip). Endpoint = either a flip-flop's data pin (D input captures data) or an output port (data leaves the chip). Everything in between is combinational logic: AND gates, OR gates, adders, muxes, inverters - all the logic that computes the result. The sum of all gate delays + wire delays along this path is the path delay that STA measures.
STA analyzes 4 fundamental path types in digital circuits. Every timing path has a startpoint (port or FF clock pin) and endpoint (FF data pin or output port).
PATH TYPE 1: INPUT → REGISTER
PATH TYPE 2: REGISTER → REGISTER (Most Common)
PATH TYPE 3: REGISTER → OUTPUT
PATH TYPE 4: INPUT → OUTPUT (Combinational)