摘要： -clock_fall ：指明外部寄存器用该时钟的下降沿采样数据；常用于DDR接口-add_delay：指明还有另一个外部寄存器与该端口相连；常用于DDR接口 阅读全文

摘要： 1、If a user does want to use this, use the –add option , so their uncertainty is additive to that calculated by derive_clock_uncertainty.2、set_clock_uncertainty applied to a clock does not have its uncertainty propagate to generated clocks downstream. The user need to apply uncertainty to those cloc 阅读全文