CodiodeCodiode
Home
Problem Solving
Skill Tracks
My Assignments
Contests
Leaderboard
Community
Settings
Codiode/Problems/Sequential Logic

Synchronous Counter Carry Chain

HardLogic CircuitTiming Diagram

A 4-bit synchronous up-counter increments its state on the positive edge of CLK when EN is HIGH, while the combinational carry-out COUT asserts when EN and all state bits are HIGH.

Five input signals are shown: CLK (clock, period 2), EN (count enable), and the lower three state bits Q0, Q1, and Q2.

Trace the most significant bit Q3 (initially 1) and the combinational carry-out COUT across all 16 time steps.

Constraints

  • Output Q3 updates only on the LOW-to-HIGH transition of CLK.
  • Output COUT is strictly combinational and reflects the logical AND of EN, Q0, Q1, Q2, and Q3 instantly.

Topics

Sequential LogicTiming AnalysisCounters

Solve this problem

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

This problem is part of Codiode Pro. The statement above is free to read.

Sign in to solveSee what Pro unlocks

The circuit builder and code editor need a desktop screen. On a phone, read the problem here and open it on a laptop to solve.

Related problems

  • 3-bit Ripple Counter from Toggle Flip-FlopsEasy
  • D Latch from a 2:1 MUXEasy
  • 2-bit Ring CounterEasy
  • T Flip-Flop from a D Flip-FlopEasy
  • Handshake Deadlock Due to Early ResetHard
  • Reconvergence of Individually Synchronized BitsHard
  • Debug: Asynchronous Clear GlitchHard
  • Clock Gate Enable Crossing DomainsHard

Browse all problems · Learning tracks