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84 Threads found on False And 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 (...)
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 (...)
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. (...)
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 (...)
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
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?
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 (...)
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
1- the designer who made the design could provide the paths which could be relax via false path or multi-cycle. 2- if your design meet the timing/area/power, you do need to add constraint. 3- if you are not able to reach the timing, you need to analyze the worst path and confirm, that a true (...)
Hi all, I wanted to know what is "false path" with one or two good examples/... Thanks
in clock domain crossing, you set false path for hold while doing synthesis because two clocks are asynchronous and timing cannot checked. But you set set_max_delay and set_min_delay on these paths. so that data should reach after specified delay.
Just want to know the opinion of the forum. Is it preferred to use exactly the same set of constraints for both synthesis using DC, and STA using PrimeTime? Does the synthesis tool use the false path specifications, or max transition constraints? Or can we use a simpler constraint file to do synthesis, and then use a (...)
defining false path is only required to meet the timing. if you could do without it's safer, because you are sure to not cut any unwanted path.
hai friends i have a setup violation in a path starting in the Q pin of a flipflop followed by some logic blocks and ending in the D pin of the same flip flop how can i over come this can i set false path or multicycle path help me........... thank you
Hi, I am confused which should be set for asynchronous control signal, false path or recovery and removal constrain? Could you tell me how to choose and why? Thanks!