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Codiode/Problems/Combinational Logic

Implicit Wire Bug in Datapath

HardLogic CircuitDebug

A 2-bit bitwise OR circuit combines status flags from dual redundant sensors to produce a unified 2-bit output Y.

Expected behavior:

| A1 | A0 | B1 | B0 | Y1 | Y0 | |------|------|------|------|------|------| | 0 | 0 | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 1 | 0 | 1 | | 0 | 0 | 1 | 0 | 1 | 0 | | 0 | 0 | 1 | 1 | 1 | 1 | | 0 | 1 | 0 | 0 | 0 | 1 | | 0 | 1 | 0 | 1 | 0 | 1 | | 0 | 1 | 1 | 0 | 1 | 1 | | 0 | 1 | 1 | 1 | 1 | 1 | | 1 | 0 | 0 | 0 | 1 | 0 | | 1 | 0 | 0 | 1 | 1 | 1 | | 1 | 0 | 1 | 0 | 1 | 0 | | 1 | 0 | 1 | 1 | 1 | 1 | | 1 | 1 | 0 | 0 | 1 | 1 | | 1 | 1 | 0 | 1 | 1 | 1 | | 1 | 1 | 1 | 0 | 1 | 1 | | 1 | 1 | 1 | 1 | 1 | 1 |

A typo in the original hardware description language caused an implicit 1-bit wire declaration, severing the upper bit of the datapath in the synthesized netlist. Simulation shows Y1 = 0 for input A1=1, A0=0, B1=0, B0=0. The output Y1 remains 0 for all inputs. Inspect the circuit and correct the fault.

Constraints

  • Do not add additional logic gates.
  • Repair the broken connection to restore the full 2-bit datapath.

Topics

logic-gatesdatapathdebugging

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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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