Author Topic: set_multicycle_path questions  (Read 1133 times)

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Offline promachTopic starter

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set_multicycle_path questions
« on: September 03, 2020, 09:04:37 am »
For multicycle path constraint , what is the difference between the usage of -start and -end ?

Why "hold will return back to 0 cycle check" ?

« Last Edit: September 03, 2020, 09:27:56 am by promach »
 

Offline NorthGuy

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Re: set_multicycle_path questions
« Reply #1 on: September 03, 2020, 01:38:17 pm »
Use -start to count cycles of the source clock.

Use -end to count cycles of the destination clock.

Doesn't matter if both clocks are the same.
 

Offline promachTopic starter

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Re: set_multicycle_path questions
« Reply #2 on: September 03, 2020, 02:58:36 pm »
Quote
Use -start to count cycles of the source clock.

Then the blue arrow in Figure 8 is wrong ?


Besides, how to derive the equation Hold cycles = <setup path multiplier> - 1 - <hold path multiplier> in https://www.xilinx.com/support/documentation/sw_manuals/xilinx2013_1/ug903-vivado-using-constraints.pdf#page=79  ?
« Last Edit: September 03, 2020, 03:02:53 pm by promach »
 


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