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Best-Case Hold Timing Path Analysis; Worst-Case Timing Path Analysis; Best to Worst Case Timing Analysis
Source: PrimeTime User Guide Version T-2022.03
Okay, let's take this gently. Under best-case conditions, gates switch fastest, so the real risk is a hold violation, not setup. That is why this path matters. See the launch clock reaching DL1 through the short min_path@BEST? The data then races through the combinational logic toward DL2. Does that click? Hmm, look here. The capture clock at DL2 arrives later along max_path@BEST. Oh, that's clean. A fast data launch plus a delayed capture clock shrinks the safety margin against the hold@BEST requirement. So in best-case analysis, we chase the shortest data delay and the longest clock skew to prove the value still holds. Want to check that edge?
Okay, let's take this gently. This board maps the worst-case timing path between two latches, DL1 and DL2. The critical finding here is how clock skew interacts with data delay under stress. See the max_path@WORST arc? It traces the slowest data route through the combinational logic to the setup@WORST window. That defines our maximum frequency limit. Hmm, look at the clock tree though. The launch clock takes a longer max_path route to DL1, while the capture clock uses a min_path@WORST to DL2. Oh, that's clean. This specific skew actually helps setup time by delaying the launch edge relative to the capture. Does that click? We verify the data arrives before the skewed capture edge closes the window.
Okay, let's take this gently—first, we'll look at the best-case timing path. In the best-case scenario, the timing paths are analyzed under optimal operating conditions. This means that the delays are minimized, and the setup and hold times are at their most favorable. Now, see this bit? The worst-case timing path is the opposite. Here, the analysis is done under the least favorable conditions, where delays are maximized, and setup and hold times are at their worst. Let's walk through it. To transition from best-case to worst-case, you use the command 'set_operating_conditions WORST'. This sets the environment to the worst-case conditions. Then, to report the timing, you use 'report_timing -delay_type max' for the worst-case. For the best-case, you would use 'set_operating_conditions BEST' and 'report_timing -delay_type min'. Does that click? These commands help you switch between the two scenarios and get the timing reports you need. Nice—keep going. Understanding these transitions and commands is crucial for ensuring your design meets all the necessary timing requirements under different operating conditions.