2：fab一般会有推荐，但margin都巨大，非常保守。如果是test chip不留没关系，量产的setup可不留，hold...
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...
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:...
尽管set_bus_skew命令可以设置一个总线偏斜约束到同步跨时钟域中,但这种做法是多余的,因为setup和hold检查已经可以确保在两个时序安全的同步跨时钟域路径间安全切换。 总线偏斜约束不属于时序例外,和set_data_check一样,它属于时序断言。因此,总线偏斜约束不会被时序例外约束,如set_clock_group,set_false_path,set_m...
set_clock_uncertainty -fall_from [get_clocks {clk125}] -fall_to [get_clocks {clk125}] -setup 0.003 set_clock_uncertainty -rise_from [get_clocks {clk125}] -rise_to [get_clocks {clk125}] -hold 0.003 set_clock_uncertainty -rise_from [get_clocks {clk125}] -fall_to [get_clocks ...
一、序言 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…
2.4.1.6.1. Set Clock Latency (set_clock_latency) 2.4.1.6.2. Clock Uncertainty 2.4.1.7. Constraining CDC Paths 2.4.2. I/O Constraints 2.4.3. Delay and Skew Constraints 2.4.4. Timing Exception Constraints 2.4.5. Delay Annotation 2.5. Timing Report Descriptions ...
set_input_delay -clock ext_clk -max 0.0 [get_ports din*] set_input_delay -clock ext_clk -min 0.0 [get_ports din*] 4) Undestand the setup and hold realtionship between ext_clk and fpga_clk. You can run TimeQuest and do a report_timing -setup and -hold between these...
If the user has set_clock_uncertainty assignmentselsewherein their .sdc files, those assignments will have priority. If the user’s set_clock_uncertainty assignments or the derive_clock_uncertainty assignment has the -add option, then the uncertainties will be additive....
Uncertainty = [(sum(Input Jitter2))^1/2]/2 For calculation using only one clock (one flip-flop,e.g., IOB setup/hold) the equation is as follows: Uncertainty = [(Input Jitter2)^1/2]/2 Files(0) No records found. 本篇文章对您是否有用?