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Specify the selection with a truth table
List every input combination and define its expected output.
पाठ पढ़ना मुफ़्त है। प्रगति सेव करने के लिए नामांकन करें।
अनुवाद अभी उपलब्ध नहीं है। मूल पाठ दिखाया गया है। (English)
Learning goals
- Enumerate every combination of three inputs
- Check that changing the unselected input does not change the output
Fix the selection rule first
Three one-bit inputs have 2 × 2 × 2 = 8 combinations. Write columns in the order a, b, sel. Copy a to the output for sel=0 and b for sel=1. This is the reference for your code.
When both data inputs match, changing sel leaves y unchanged. Testing only those cases can miss a reversed selection rule.
| a | b | sel | Expected y |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 0 |
| 0 | 1 | 0 | 0 |
| 0 | 1 | 1 | 1 |
| 1 | 0 | 0 | 1 |
| 1 | 0 | 1 | 0 |
| 1 | 1 | 0 | 1 |
| 1 | 1 | 1 | 1 |
Vary the unselected input
Keep sel=0 and a=1, then change b from 0 to 1. y should stay at 1. If b affects the output while sel=0, the circuit does not match this MUX specification.
This table specifies the combinational output y. Checking sampled_y also requires the clock-edge timing. Keep selection rules distinct from the timing of storage.
खुद आज़माएँ
Which case reveals a reversed selector: a=0, b=0 or a=0, b=1?
व्याख्या पढ़ें
Use a=0, b=1. sel=0 should produce 0 and sel=1 should produce 1, so a reversal becomes visible.