1. 定义: mutually exclusive clock
CLK1和CLK2是同步的,但逻辑上互相排斥
2. fully mutually exclusive clocks
这实际上是错误的。DC只会用S和T的最大值,timing path S和T会被over-constraint
解决方法:
set_false_path -from [get_clocks CLK1] -to [get_clocks CLK2]
set_false_path -from [get_clocks CLK2] -to [get_clocks CLK1]
或
set_clock_groups -logically_exclusive -group CLK1 -group CLK2
3. partially mutually exclusive clocks