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

Up/Down Counter: Enable Direction Latch

HardLogic CircuitTiming Diagram

A positive-edge-triggered 2-bit counter increments when DIR is 1 and decrements when DIR is 0, but only updates its state when EN is 1.

Five signals are shown: CLK (clock, period 2), EN (active-high enable), DIR (direction control), and Q1 and Q0 (the 2-bit output state, both initially 0).

Trace Q1 and Q0 across all 12 time steps.

Constraints

  • The counter state only updates on the LOW-to-HIGH transition of CLK.
  • Changes to DIR while EN is 0 do not immediately affect the output but dictate the direction of the next active count.

Topics

sequential-logictiming-diagramcountersstate-elements

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