Description The set_false_path command identifies specific timing paths as being false. The false timing paths are paths that do not propagate logic level changes. This constraint removes timing requirements on these false paths so that they are not considered during the timing analysis. The path ...
因为reg到reg之间的设定,reg1/Q到reg2/D,必然会打断reg1的CP到Q的timing arc ,从而影响到了同步paths check,此时可以准备两套sdc,分别对timing 进行check 4)set_max_delay命令优先级 set_clock_group之后,对于异步时钟组的时钟,设置从reg1的cp端口到reg2的D端口,这种合法的起始点,是不能生效的,但是从reg1...
先上结论 : 1. 同步时钟域: 不需要timing check 的 path 才用 set_false_path ,only disable timing analyze; 2. 异步时钟域: set_clock_group -async 同步时钟域和异步时钟域 的 Timing window: 如图,在cro…
指定禁止路径的起点(时钟、端口、接脚或单元)。如果你没有指定一个from_list,所有终点在to_list的路径都被设为禁止。from_list可以包含时钟、接脚或端口。如果你指定一个时钟,所有起点与指定时钟相关的路径都会有影响。如果你指定一个内部接脚,接脚必须是一个路径的起点(比如一个触发器的时钟接脚)。如果一个单元...
`set_false_path`和`set_clock_groups`是两种常用的SDC(Synopsys Design Constraints)命令,用于处理特殊时序关系。本文将详细介绍这两个命令的使用场景、语法规则以及实际应用技巧。## 2. set_false_path命令详解### 2.1 基本概念`set_false_path`用于声明设计中不需要进行时序分析的路径。这些路径可能是:-功能上...
Set False Path(set_false_path)约束使您能够从时序分析中排除路径,例如测试逻辑或与电路操作无关的任何其他路径。您可以指定路径的源(-from),公共元素(common through elements)(- thru)和目的地(-to)元素。 下面的SDC命令指定从以A开头的所有寄存器到以B开头的所有寄存器的伪路径异常(false path exceptions): ...
You access this dialog box by clicking Set False Path on the Constraints menu in the TimeQuest Timing Analyzer, or with the set_false_path Synopsys Design Constraints (SDC) command described in the SDC syntax reference. A variation of this command is available by selecting a path in the ...
Hi, I've tried to constrain my project in timequest. One register in design is clocked by 200 Hz, so i decided not to constrain this clock, but use set_false_path SDC command. set_false_path -from [get_pins {Gen|clkA|regout}] -to [get_pins {Diagn|regA|clk}] regA is the ...
Should be no problem to use the sdc constraint, if there a problem, you will see the constraint being ignored in the Report Ignored SDC in the Timing Analyzer. Let me add more info: The set_false_path command tells the timing analyzer not to analyze a path or group of pat...
Within Vivado (and SDC/XDC) path enumeration is done the same way for all commands that need to select paths (these being the timing exception commands, set_false_path, set_multicycle_path, set_min_delay, set_max_delay and the path reporting commands, like report_timing, get_timing_paths...