Stimulus alone proves nothing. A monitor passively rebuilds transactions from DUT pins, a reference model predicts what the DUT should have done, and a scoreboard compares the two streams.
Three rules carry the whole topic. The monitor never drives a signal, the scoreboard compares observed against predicted, and end-of-test checks prove compares happened before any PASS.
Lesson | What it covers | Path |
|---|---|---|
Input-only sampling, accepted-beat reconstruction, one broadcast copy per consumer. | Required | |
FIFO compare for in-order DUTs, by-id lookup for out-of-order DUTs. | Required | |
Field masks, first-difference dumps, drain windows, watchdogs, leftover checks. | Required | |
Transaction-level predict functions and coverage sampled from observed traffic. | Recommended | |
The project step: two monitors, an in-order scoreboard and end-of-test checks for PacketFIFO, in one runnable bench. | Recommended |
Path tells you how to spend your time. Required is the core first pass for building a layered testbench. Recommended is what most learners should read. Optional is reference, specialist or revision material that you can return to later.
Nothing checked anything. The PASS is hollow: a broken generator, a miswired monitor, or a disabled driver all produce zero compares. End-of-test checks must fail an empty scoreboard.