Primary debug scenario

Symptom: Write burst hangs. AW channel completes. W beats stop after 2 of 4. B never returns.

Triage steps

1. Freeze one interface boundary and list accepted AW items plus accepted W beats by rising edge; do not count visible VALID cycles.

2. For the selected AW, verify that AWLEN+1 equals the accepted W-beat count and WLAST is on the final accepted beat.

3. Find the first missing event: source stopped offering, destination stopped accepting, converter lost association, or route no longer matched.

4. If a width converter splits beats, reconcile its upstream acceptance, internal occupancy and downstream completions for the same write.

5. Check B only after proving the AW and final-W prerequisites; then follow BID and the stalled B offer to its accepting edge.

Common pitfalls

• Checking only AW without following W channel completion.

• WLAST missing or on wrong beat.

• Bridge dropping W beats during width conversion.