Hold, setup check for multi cycle path

[sun_ray]

At which clock edge do we check the hold and setup violations for a multi cycle path? Please provide valid reasons behind your answer.

 

[Anuvesh]

if provide multicycle path 3 then we check setup time at 4th edge and we check the hold check at the 1st edge of the capture clock signal.

 

[sam536]

To Check Setup : The setup multiplier Can be N. The launch will happen at 0th clock cycle and setup capture will happen at Nth clock cycle.


To check zero cycle hold check :
set_multicycle_path -hold 1

The rule is: Hold cycle = (setup argument) -1 - (hold argument)

Based on this equation, you need to derive a hold multiplier value to be specified in the set_multicycle_path command.

In the above example, to do a "zero" cycle hold check, 0 = (2) -1 - (hold argument)
; Hold argument (multiplier) = 1

Therefore, the hold multiplier should be specified as 1 to move the hold check back to the original edge at 0 ns.


hope this is clear.