二、Max/Min_delay约束 在设计中,有时需要限定路径的最大时延和最小时延,如没有特定时钟关系的异步信号,但需要限制最大时延和最小时延,也可以对端口到端口(中间无寄存器)的路径设置最大时延和最小时延,设置最大时延和最小时延会影响路径的setup和hold时序分析,它会覆盖默认的时序约束。 设置路径最大时延和最小时...
-hold值是用来声明将capture edge从默认位置向后移动的cycle数(与有效setup的相对位置),默认值为0。 下面的图描述了multicycle路径的例子。在没有timing exception情况下,setup关系是从0到10,hold关系是从0到0。设置multicycle后,setup关系变为从0到50,而这也隐形改变了hold关系,即从0到40。为了将hold关系的captu...
这下都清晰了,其实TimeQuest是借用了register to register的setup slack的分析模型来检查,布局布线后的延时是否大于我们set_max_delay中设置的延时。由图可以看到,clk经过变换达到引脚sr_clk(包含PLL的相位偏移修正)共是3.045ns,这点也可以从data arrive path上看出,然后将latch edge time设置为set_max_delay的值这样...
这下都清晰了,其实TimeQuest是借用了register to register的setup slack的分析模型来检查,布局布线后的延时是否大于我们set_max_delay中设置的延时。由图可以看到,clk经过变换达到引脚sr_clk(包含PLL的相位偏移修正)共是3.045ns,这点也可以从data arrive path上看出,然后将latch edge time设置为set_max_delay的值这样...
The maximum delay is similar to changing the setup relationship (latching clock edge - launching clock edge), except that it can be applied to input or output ports without input or output delays assigned to them. Maximum delays are always relative to any clock network delays (if the source ...
The maximum delay is similar to changing the setup relationship (latching clock edge - launching clock edge). Maximum delays are always relative to any clock network delays (if the source or destination is a register) or any input or output delays (if the source or d...
If the path ending point is on a sequential device, the tool includes clock skew and library setup time in the computed delay. If the ending point has an output delay specified, the tool adds that delay to the path delay.-from from_listSpecifies...
If you are failing setup timing on internal paths, you should probably not use set_max_delay. There is probably some other explanation for why you are failing timing, such as a long path delay due to physical constraints at the source or destination or you have too much combinational logic...
The path appears to be passing setup but failing hold due to the requirment being min delay of 0.0. Here is the timing report attached. LikeReply mistercoffee (Member) 5 years ago **BEST SOLUTION** It's okay, I found it. I had a slightly different reg name for p...
In the first, non-exception case, the destination clock path delays include destination FD setup time, clock uncertainty, clock pessimism and the route the clock took up to the FD. In the second case with a set_max_delay exception, only the FD setup time is included. This m...