Skip to question

Q125FreeDesign Verification

Acknowledge Without an Outstanding Request

Difficulty
Easy
Topic
Waveform Debugging
Language
SV
Interview prompt

Question

Only one request may be outstanding. Sampling req high creates an outstanding request; sampling ack high clears it. The outstanding row shows state immediately after each edge. ack may be 1 only when a request is already outstanding or req is 1 on that same edge. Which assertion fails at C5?

Waveform for Acknowledge Without an Outstanding Request. Signals: req, ack, outstanding. Numbered markers identify sampled columns.
Read the sampled columns from left to right, then test each choice against the stated timing rule.
Choose one

Answer choices

  1. A. Every req pulse must last two cycles.
  2. B. ack may be high only for an outstanding or same-cycle request.
  3. C. outstanding must stay high for the rest of simulation.
  4. D. req and ack must always rise together.
Continue practicing
Q1128 · Protocol VerificationCheck a single-outstanding request/grant protocolMediumPQ055 · Protocol CheckingFour-Phase Request/Acknowledge MonitorMediumQ015 · FSMsControl a request/acknowledge handshakeMediumQ902 · Reference ModelsTrack multiple outstanding requests by IDMediumPQ388 · Temporal ChecksRequest and acknowledge latency assertionEasyP