Intel® Quartus® Prime Pro Edition User Guide: Timing Analyzer

ID 683243
Date 10/04/2021
Public

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2.6.5.5. Creating Clock Groups (set_clock_groups)

The Set Clock Groups (set_clock_groups) constraint allows you to specify which clocks in the design are unrelated.

The set_clock_groups command allows you to cut timing between unrelated clocks in different groups. The Timing Analyzer performs the same analysis regardless of whether you specify -exclusive or -asynchronous groups. You define a clock group with the -group option. The Timing Analyzer excludes the timing paths between clocks for each of the separate groups.

The following tables show the impact of set_clock_groups.

Table 24.  set_clock_groups -group A
Destination\Source A B C D
A Analyzed Cut Cut Cut
B Cut Analyzed Analyzed Analyzed
C Cut Analyzed Analyzed Analyzed
D Cut Analyzed Analyzed Analyzed
Table 25.  set_clock_groups -group {A B}
Destination\Source A B C D
A Analyzed Analyzed Cut Cut
B Analyzed Analyzed Cut Cut
C Cut Cut Analyzed Analyzed
D Cut Cut Analyzed Analyzed
Table 26.  set_clock_groups -group A -group B
Destination\Source A B C D
A Analyzed Cut Analyzed Analyzed
B Cut Analyzed Analyzed Analyzed
C Analyzed Analyzed Analyzed Analyzed
D Analyzed Analyzed Analyzed Analyzed
Table 27.  set_clock_groups -group {A C} -group {B D}
Destination\Source A B C D
A Analyzed Cut Analyzed Cut
B Cut Analyzed Cut Analyzed
C Analyzed Cut Analyzed Cut
D Cut Analyzed Cut Analyzed
Table 28.  set_clock_groups -group {A C D}
Destination\Source A B C D
A Analyzed Cut Analyzed Analyzed
B Cut Analyzed Cut Cut
C Analyzed Cut Analyzed Analyzed
D Analyzed Cut Analyzed Analyzed