Conflicting exceptions - False path and Multicycle Path

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harpv

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Hi,

I want to know what happens when there's a conflict between the false path and multicycle path exception definition. Which one takes precedence when there happens to be a path such that it's getting sensitized by both the fp and mcp timing exceptions?

Thanks,
Hari
 

False path is more restrictive, and then this one has priority over the multicycle path exception.

Same idea for set_max_transition, you could not relax with this command, the tool will use the most constrainted value provided (or not) by the liberty or the constraint.
 
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    harpv

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Thanks Rahul.
I think the synthesis tool always try to do a "easier" job in term of meeting the timing constraint. i.e. meeting the constraint of "false_path" is way easier than meeting the constraint of MCP or even SMT.
Is it correct?

rahul.achates said:
Below is the order of precedence - Leftmost having higher priority.
SFP > MCP > SCP > SMT
Click to expand...
 

All constraints are having specific to a condition , one constraint can't replace another.

In Hardware , there are many signals and sometime it might be possible when you have apply more then one constraint on same signal , in that case, tools will look for order of precedence and final constraint will be applied having higher priority.

False path and MCP are not same.



Rahul
 
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