HDL & Verification
What characterizes a self-checking testbench?
- AA person visually inspects waveforms and judges correctness every time
- BIt automatically compares outputs with expected values and reports pass or fail itself
- CThe circuit is manufactured and then checked in silicon
Show answer and explanation
Answer: B. It automatically compares outputs with expected values and reports pass or fail itself
Checking waveforms by eye is handy for small circuits, but as tests multiply, mistakes slip through and rechecking after every change is impractical. A self-checking testbench computes or looks up the expected output for each input, compares it automatically with the design's output and reports any mismatch as an error. Thousands of tests can run unattended overnight with only the results to review.
- A. That is not self-checking.
- B. Correct. Large numbers of tests can run automatically.
- C. It runs in simulation before manufacturing.