set_clock_uncertainty -hold =(margin) post-layout STA: set_clock_uncertainty -setup = jitter(+margin) set_clock_uncertainty-hold =(margin) Margin is related to process technology. Generally, foundry factory has the recommented value. Uncertainty comes from the PLL jitter, clock frequency, clock...
刚开始学dc,有些用法比较模糊,记录一下set_clock_latency与set_clock_uncertainty的理解:1,set_clock_latency用于描述时钟源到寄存器时钟输入端的延迟,包括source和network延迟,在pre-layout约束时,同时使用;在post-layout时,准确的说,cts之后,只设置source latency,因为network 延迟已经包含在sdf里了。如法如下:...
clock_uncertainty 主要是前端留给后端的CTS的，其次是clock源的jitter。所以CTS之后，如果对时钟源有信心...
2,set_clock_uncertainty可以理解为clock skew 即在pre-layout时模拟cts之后,由于插入buffer、数据路径长度不同,而引起的clock到各个寄存器时钟输入端延迟时间不同。在pre-layout包含jitter+clock,post-layout只能用jitter set_clock_uncertainty value [-from object_list -to object_list] [-rise] [-fall] [-setu...
也是可以设置为0，在后端插入时钟树之后如果想要留有margin，则再选择set_clock_uncertainty -hold 0.1...
set_clock_latency, set_clock_uncertainty and set_propagated_clock commands. Please adjust your script accordingly. set_clock_uncertainty半个周期也太夸张了。一般根据时钟源来设 我们用TSMC018工艺clock_uncertainty经验值应该是setup 1ns,hole 0.5ns
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_u
数字IC设计后端流程中,EDA工具一般是SDC时序约束驱动的编译, clk有一个set_clock_uncertainty约束,用来...
在时序约束中,对时钟的约束除了set clock latency,set clock uncertainty,set input jitter外,还有一条set bus skew的约束命令。该命令主要用于跨时钟域的场景中,下面将对set bus skew的使用进行详细的介绍。 二、Set Bus Skew 2.1 基本概念 Set Bus Skew用于在多个跨时钟域路径中设置一个最大的偏斜要求,可以限制...
关于set_clock_uncertainty的两点注意事项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....