Timing exceptions are subject to strict precedence and priority rules. The most important rules are as follows:
- The more specific the constraint, the higher the priority. For
set_max_delay -from [get_clocks clkA] -to [get_pins inst0/D] 12 set_max_delay -from [get_clocks clkA] -to [get_clocks clkB] 10
set_max_delayconstraint has a higher priority because the
-tooption uses a pin, which is more specific than a clock.
- The exceptions priority is as follows:
set_clock_groups command is not
considered a timing exception even though it is equivalent to two
set_false_path commands between two clocks. It has
higher precedence than the timing exceptions.
set_disable_timing commands disable timing analysis on
specific portions of the design. They have higher precedence than the timing