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130 Threads found on False Path
Like i have loop, why i can't disable with false path?
Can I always set false path for violation occurring at inter-clock-path ? ( provided , CDC is taken care in RTL ) Yes. How to solve Intra-clock-path timing violations ( setup and hold ) Provided that you follow good FPGA design practices (mainly using dedicated clock routes) - hold time violations will rare
Changing RTL is always the easiest option. Have you got register merging turned off? Than can help reduce the register fan outs. All false paths and multi cycle paths specified? Finally you can try overconstraining a single path using a set max delay, but this can often make it harder to route adjacent nets and is a rather (...)
Hello all, I am aware of a similar post on edaboard with this question. However I am unable to continue that thread as it is closed. Here I am asking the similar question. Will ATPG tool be able to generate patterns which simulate false paths and multi-cycle paths? I am sure false paths will not be (...)
There are two clock made constraint as create_clock. If I don't set false_path about these two clock. After CTS, are these two path balance ? What action does CTS handle false_path constraint ? For CTS, these two clocks are treat as independent and have not balance ?? Thanks.
Hey, false path constraint is much more strict, as you are saying that paths between launching and capturing flip flops will not exist, may be due to some architectural condition. Hence, tool will not time those paths. I guess SCP is single cycle paths. I am not sure about SMT. Thanks, Abhishek (...)
I would suggest to have the following constraint first. 1. clock period 2. input delay 3. output delay 4. clock uncertainity 5. clock latency 6. set load 7. set input transition 8. false path / Multi-Cycle path ( between the clock domains if any ).
Hi everyone, What is the difference points between set_false_path & set_disable_timing? When should we use which suitable command? BR,
Hi. I'm trying to implement including false path and multi cycle path RTL code for test design compiler. So does anyone know where some example codes are ?
112126 This image comes from Altera AN433. As we can see, AN433 requires to constraint the Opposite-Edge Capture Center-Aligned Input with multicycle and false path exception. However, in my opinion, we just have to constraint that with false path exception which would remove the analysis of same-edge data transfer lab
I understand that a set_multicycle_path can be specified between two different clock domains. If the source and destination clocks are synchronous I believe there isn't much confusion. But if the clock domains are asynchronous, how does the STA tool handle it? I haven't seen this getting used in my experience yet, just curious about
Hi, I want to know what happens when there's a conflict between the false path and multicycle path exception definition. Which one takes precedence when there happens to be a path such that it's getting sensitized by both the fp and mcp timing exceptions? Thanks, Hari
Hi? I trying to find false and multi-cycle path in design by design compiler. But i dont know how can i find false and multi cycle path in design by design compiler?
Hi, I am trying to enumerate all false paths of the circuit using PrimeTime. I tried -true -false and -justify switches but it seems that these options have been made obsolete since the 2011.12 release of PrimeTime and are no longer supported. I am wondering whats the new commands? Thanks
In my design, there are two independent clocks in functional mode and cross clock path are defined as false path. But in DC scan mode, these two clocks will be grouped into a single scan clock. Do we need to fix timing violation on these cross clock paths which become driven by the same scan clock in scan mode?
Hi All, What Timing Constraints should be applied to Synchronizers? Should it be false path? MultiCycle path? Max Delay? Etc? Thank you!
The basic questions will be on 1. Clock constraints (master clock, generated clock, clock skew, jitter, clock network delay, source delay) 2. Input and output constraints 3. Virtual clock and the use of it 4. false path and multi cycle path. How will you identify them. 5. How will you fix setup and hold violations 6. What is PVT corner and (...)
Hi All, I am using Xilinx's Vivado 2013.3 for generating the *.bin file. There are a lot asynchronous paths in my design. for example if I have grouped the signals like : # in CLK1 domain set GROUP1 ; set GROUP1 ; set GROUP1 ; # in CLK2 domain set GROUP2 [get_cells {sig_
I have a simple question about false paths: why do they exist? I mean, if they can never "happen", why does the synthesis tool generate (or keep) them? I'm not talking about asynchronous paths, but paths that will never really occur. Like this one: Thanks in advance
A common example would be a slow microcontroller interface to a high speed clock domain. In this case, the controller sends an address + enable to the other clock domain. The other clock domain may need only to double-register the enable. This is one possible false path for the "synchronizer". At this point, the address isn't changing. The m