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

Up/Down Counter: Direction Change Mid-Count Waveform

EasyLogic CircuitTiming Diagram

A 3-bit synchronous up/down counter updates its internal state on every positive clock edge, incrementing by 1 when UP_DN is HIGH and decrementing by 1 when UP_DN is LOW. Five signals are shown: CLK (clock, period 2), UP_DN (direction input), and Q2, Q1, Q0 (counter outputs). The initial state of the counter is 5 (Q2=1, Q1=0, Q0=1). Trace Q2, Q1, and Q0 across all 12 time steps.

Constraints

  • Output changes only occur on the LOW-to-HIGH transitions of CLK.
  • The direction input UP_DN is evaluated exactly at the rising edge of the clock.
  • Changes to UP_DN mid-cycle do not affect the output until the next rising clock edge.

Topics

Sequential LogicWaveformCounters

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