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Explorer
Explorer
5,905 Views
Registered: ‎03-06-2014

How to apply set_property ALLOW_COMBINATORIAL_LOOPS TRUE to pass combinatorial loops?

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Dear all,

While I was searching for a solution that I have like this in Vivado, I have a problem of the combinatorial loop in my design targeting design of a ring oscillator. Can anyone please let me know in the following command what should I add in my xdc file to make it run?? [get_nets] ?? [get_pins] ?? [get_ports] ?? or etc. ?? I did all trials but it does not work !!
Thank you so much,

 

set_property ALLOW_COMBINATORIAL_LOOPS TRUE ...???
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Explorer
Explorer
8,784 Views
Registered: ‎03-06-2014

Re: How to apply set_property ALLOW_COMBINATORIAL_LOOPS TRUE to pass combinatorial loops?

Jump to solution

Dear all,

 

Nobody answered my question in this post, but eventually, I found my answer by lots of trials. I put the correct answer here for future designers facing this problem in order to SAVE their time and NOT to spend a time to find the solution :))

 

Here is the correct set_property that must be set. The two latter commands are also REQUIRED in order to pass DRC, Implementation and finally bitstream generation. 

 

P.S. : There is nothing clearly mentioned in the Documentation for Tcl scripting for this property !!

 

set_property ALLOW_COMBINATORIAL_LOOPS true [get_nets -of_objects [get_cells <cellname>]]

set_property SEVERITY {Warning}  [get_drc_checks LUTLP-1]

set_property SEVERITY {Warning} [get_drc_checks NSTD-1]

 

This will SOLVE the problem and will work very nice ! :)) Enjoy !

 

Hope it could be useful for all.

 

Regards,

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Highlighted
Explorer
Explorer
8,785 Views
Registered: ‎03-06-2014

Re: How to apply set_property ALLOW_COMBINATORIAL_LOOPS TRUE to pass combinatorial loops?

Jump to solution

Dear all,

 

Nobody answered my question in this post, but eventually, I found my answer by lots of trials. I put the correct answer here for future designers facing this problem in order to SAVE their time and NOT to spend a time to find the solution :))

 

Here is the correct set_property that must be set. The two latter commands are also REQUIRED in order to pass DRC, Implementation and finally bitstream generation. 

 

P.S. : There is nothing clearly mentioned in the Documentation for Tcl scripting for this property !!

 

set_property ALLOW_COMBINATORIAL_LOOPS true [get_nets -of_objects [get_cells <cellname>]]

set_property SEVERITY {Warning}  [get_drc_checks LUTLP-1]

set_property SEVERITY {Warning} [get_drc_checks NSTD-1]

 

This will SOLVE the problem and will work very nice ! :)) Enjoy !

 

Hope it could be useful for all.

 

Regards,

Tags (1)