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

Ring Counter: 8-Bit for 8-Phase Clock Generation

MediumLogic CircuitBuild

Time-division multiplexers and motor control systems rely on multi-phase clocks to sequence operations. An 8-phase ring counter generates eight non-overlapping channel outputs directly. This avoids the area penalty of pairing a binary counter with a combinational decoder.

The circuit is an 8-bit shift register with its final output fed back to its first input. Exactly one bit of the 8-bit output bus Q remains HIGH at any given clock cycle.

When rst is 1, the bus Q must initialize to 10000000 in binary. When rst is 0, each rising clock edge shifts the active bit: Q[7] routes to Q[0], Q[0] routes to Q[1], and so forth.

| rst | Q (binary) | Q (decimal) | |-------|--------------|---------------| | 1 | 10000000 | 128 | | 0 | 00000001 | 1 | | 0 | 00000010 | 2 | | 0 | 00000100 | 4 | | 0 | 00001000 | 8 |

Constraints

  • Implement an 8-stage shift register using D flip-flops.
  • Route the output of the final stage Q[7] back to the input of the first stage D[0].
  • Initialize the register state to binary 10000000 synchronously when rst is HIGH.
  • Ensure exactly one output bit is HIGH during normal operation.

Topics

Shift RegistersOne-HotRing Counter

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