Difficulty: Easy · Puzzle 2 of 6 · Topic: Temporal Corner Puzzles
Property intent: after start rises, done must be high one cycle later. Timeline: at C40 sample, start observed as 0->1 transition; C41 done=1. Determine the verdict.
property p_rose_delay;
@(posedge clk) $rose(start) |-> ##1 done;
endproperty$rose checks sampled previous value versus current sampled value.
1) $rose(start) is true at C40, so implication triggers.
2) ##1 done requires done at C41.
3) done is high at C41.Answer: PASS - sampled rise is detected at C40 and the one-cycle-later done requirement is met.
Many answers confuse asynchronous transition time with sampled assertion semantics.
If done were high at C40 but low at C41, would this still pass?