在时序报告中,可以针对两类特殊的约束专门进行报告,一类是前面介绍过的Report Exception,包含了约束set_multicycle_path/set_false_path/set_max_dealy/set_min_delay。另一类就是本文要介绍的set_bus_skew约束,对应的分析为Report Bus Skew,该报告不包含在Report Timing Summary中。 二、Set Bus Skew 2.1 约束介...
您可使用 set_bus_skew 命令来对总线设置总线偏移约束。例如,您可将 set_bus_skew 应用于使用格雷编码代替“Max Delay Datapath Only”(仅最大延迟数据路径)约束的 CDC 总线。欲知详情,请访问此链接以参阅 Vivado Design Suite 用户指南:使用约束(UG903) 中的相应内容。 对于不需要时延控制的路径,您可定义1个...
set_bus_skew -from [get_cells {{bus_reg[0]} {bus_reg[1]} {bus_reg[2]} {bus_reg[3]} {bus_reg[4]}}] -to [get_cells {{bus_clk2_reg[0]} {bus_clk2_reg[1]} {bus_clk2_reg[2]} {bus_clk2_reg[3]} {bus_clk2_reg[4]}}] 0.550 set_input_delay -clock [get_clocks ...
时序例外优先级:时序例外优先级从高到低为:Clock Grroups,False Path,Maximum Delay Path(set_max_delay)和(set_min_delay),多时钟周期约束(set_multicycle_path). set_bus_skew约束并不影响上述优先级且不与上述约束冲突。原因在于set_bus_skew并不是某条路径上的约束,而是路径与路径之间的约束。 针对同样的...
最下面fast corner/slow corner的Bus skew就是对应corner下最大延时减去最小延时,以slow corner为例,Vslow=1.547-1.528=0.019ns 四、分析路径查看 在第三章中,对datasheet报告的各部分进行了介绍,但报告只有不同corner下的值,如何查看具体的路径?这就需要借助Schematic,以打开implement阶段的schematic图为例,在Input...
## Timing Assertions Section # Primary clocks # Virtual clocks # Generated clocks # Clock Groups # Bus Skew constraints # Input and output delay constraints ## Timing Exceptions Section # False Paths # Max Delay / Min Delay # Multicycle Paths # Case Analysis # Disable Timing ## Physical ...
# Bus Skew constraints # Input and output delay constraints ## Timing Exceptions Section # False Paths # Max Delay / Min Delay # Multicycle Paths # Case Analysis # Disable Timing ## Physical Constraints Section # located anywhere in the file, preferably before or after the timing constraints ...
XDC Constraints and Their Impact on the Timing Graph Constraints with Impact on Constraints with No Impact on Timing Graph Timing Graph Constraints which Require Up-to-Date Timing Graph create_clock set_bus_skew all_fanout create_generated_clock set_clock_groups all_fanin set_case_analysis set_...
vivado下多周期路径约束(set_multicycle_path)的使用,set_multicycle_path一般在如下情况下使用,源时钟和目的时钟来自同一个MMCM、PLL等同一个IP核,或者源时钟和目的时钟是同一个时钟。只要两个时钟间可进行静态时序分析就可以。在这种情况下,即使不加set_multicycle_path的约束,只要时序分析能过,也是没有问题的,...
Due to potentially large skew between asynchronous clocks, the timing quality-of-result can be heavily impacted and prevent proper timing closure if any of the asynchronous CDC paths is timed. You are responsible for adding timing exceptions on these paths, such as set_clock_groups, set_false_...