AR# 9419


14.x Timing Closure - Suggestions to avoid the timing constraints missing the goal by 10% to 15%


I placed a timing constraint on a path, but the constraint has errors and misses the goal by 10% to 15%. What can I do to make this timing constraint pass?


If your constraint misses its timing requirement by less than 15%, and the logic delay is less than 60%, try several cost tables at effort level 5, using MPPR (Multi-Pass Place and Route).

For additional suggestions and recommendations, see the following Answer Records:
- Suggestions for avoiding high fanout signals, see (Xilinx Answer 9410).
- Suggestions for state machine optimization, see (Xilinx Answer 9411).
- Suggestions for long carry logic chains, see (Xilinx Answer 9412).
- Suggestions for I/Os 3-state enable paths, see (Xilinx Answer 9413).
- Suggestions for paths through TBUFs, see (Xilinx Answer 9414).
- Suggestions for timing through irrelevant paths such as RESET or ".SR" pin, see (Xilinx Answer 9415).
- Suggestions for using multi-cycle paths, such as a path through a ".CE" pin, see (Xilinx Answer 9416).
- Suggestions for how to avoid having too many levels of logic, see (Xilinx Answer 9417).
- Suggestions for timing constraints that miss their goals by 5% to 10%, see (Xilinx Answer 9418).

AR# 9419
Date 12/15/2012
Status Active
Type General Article
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