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Codiode/Problems/Sequential Logic

Metastability: D Transition Inside Setup-Hold Window

HardLogic CircuitTiming Diagram

A positive-edge-triggered D flip-flop enters an indeterminate metastable state if its input transitions simultaneously with the active clock edge, violating setup and hold requirements.

Three signals are shown: CLK (clock, period 2), D (input), and Q (output, initially 0).

Trace Q across all 8 time steps, using the value "X" for any period where the output is metastable.

Constraints

  • Use the character "X" (capitalized) to denote any time step where the output state is indeterminate.
  • Assume the flip-flop resolves to a valid logic level on the next positive clock edge where setup and hold times are successfully met.
  • The flip-flop holds its current state (valid or metastable) while the clock is LOW.

Topics

flip-flopsmetastabilitytiming-violationssetup-hold

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Place the gates, wire them up and watch the signals settle. Every submission runs on the same simulation engine that grades it.

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