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Codiode/Problems/Sequential Logic

Mod-N Counter with Enable: Modulus Preservation

MediumLogic CircuitTiming Diagram

A positive-edge-triggered Mod-5 counter increments its value by one on every LOW-to-HIGH transition of CLK when EN is HIGH, wrapping from 4 (100) to 0 (000), and holds its current value when EN is LOW. Five signals are shown: CLK (clock, period 2), EN (enable input), and the 3-bit counter state Q2, Q1, Q0 (outputs, initially 0, 1, and 0 respectively, representing state 2). Q2 is the most significant bit. Trace the state of Q2, Q1, and Q0 across all 16 time steps.

Constraints

  • The counter is positive-edge-triggered and only updates state on the rising edge of CLK.
  • The counter state wraps from 4 (100) directly to 0 (000).
  • Changes to EN between clock edges do not affect the stored state.

Topics

Sequential LogicTiming DiagramCounters

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