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Codiode/Problems/Combinational Logic

Operator Precedence Bug

HardLogic CircuitDebug

A comparison circuit checks two pairs of redundant sensor signals to ensure both pairs match. The circuit must output 1 only when input A equals input B, and input C equals input D.

Expected behavior:

| A | B | C | D | Y | |-----|-----|-----|-----|-----| | 0 | 0 | 0 | 0 | 1 | | 0 | 0 | 0 | 1 | 0 | | 0 | 0 | 1 | 0 | 0 | | 0 | 0 | 1 | 1 | 1 | | 0 | 1 | 0 | 0 | 0 | | 0 | 1 | 0 | 1 | 0 | | 0 | 1 | 1 | 0 | 0 | | 0 | 1 | 1 | 1 | 0 | | 1 | 0 | 0 | 0 | 0 | | 1 | 0 | 0 | 1 | 0 | | 1 | 0 | 1 | 0 | 0 | | 1 | 0 | 1 | 1 | 0 | | 1 | 1 | 0 | 0 | 1 | | 1 | 1 | 0 | 1 | 0 | | 1 | 1 | 1 | 0 | 0 | | 1 | 1 | 1 | 1 | 1 |

Simulation shows Y = 0 for input A=0, B=0, C=0, D=0. The output is incorrect. Inspect the circuit and correct the fault.

Constraints

  • Maintain the intended architecture of checking pair equalities before combining the results.
  • Use standard 2-input logic gates for all operations.

Topics

debuggingoperator-precedenceequality-logic

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.

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