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Codiode/Problems/Sequential Logic

SISO: Recirculating Register Waveform Verification

MediumLogic CircuitTiming Diagram

A 4-bit recirculating shift register shifts right and feeds its least significant bit (Q0) back into its most significant bit (Q3) on every positive clock edge when LOAD is LOW.

Three signals are shown: CLK (positive-edge-triggered clock, period 2), LOAD (active-HIGH synchronous load), and Q3 (output, initially 0). When LOAD is HIGH at a rising clock edge, the register synchronously loads the state Q3 Q2 Q1 Q0 = 0110.

Trace Q3 across all 16 time steps to verify its period-4 repetition pattern.

Constraints

  • Q3 updates only on the LOW-to-HIGH transition of CLK.
  • Synchronous load takes priority over the shift operation.
  • The register shifts right, meaning the value of Q0 from the previous cycle becomes the new value of Q3.

Topics

FeedbackSynchronous LogicShift Registers

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