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94 Threads found on Multicycle
Hi All, I have input delays set as greater than the available clock periods. For example, in my constraint file Input delay for a pin is set as 25.5ns and I am using 8 ns period clock and the path has multicycle path of 3 periods. So I m getting violation in preCTS stage as the delay is high compared to the clock period. I
See this pdf on multicycle paths multicycle paths are useful if you have a large combinational circuit that has a propagation delay that exceeds the clock period and you either can't (e.g. encrypted IP
the example above doesn't work without a multicycle constraint. I don't see why it wouldn't work without the multicycle constraint, this might have been the case in a much older technology node than today. At 50 MHz this will make timing on any part in that Vivado can implement without multicycle constraints (
An excerpt from TrickyDicky's post in #5 If you then get really stuck, look into logic locking specific parts of your chip (ie. assinging specific entities to specific regions of a chip so that they have priority there) and ensure you have specified all false and multicycle paths in your SDC file. And as a final case, specify max delay c
Hi, Can anybody tell me the advantages of using Asynchronous FIFO when we can do the clock domain crossing using multicycle path cdc (synchronizing control enable signal and holding the input data for mulitple cycles ). why go for the pains of creating a fifo and verifying it also adding significant gate count to the design. -abhinavpr
I ask this because, when we write data into the asynchronous FIFO, the data input to the FIFO and FIFO write are in same clock. So no clock domain crossing occurs at this point. When we read data from the FIFO, the read clock and the data fed circuit will be in same clock domain. Again, no clock domain crossing!! data input to th
Hello, MCP is multicycle path during capture only as we are running shift at low speed. If we provide multiple cycles, it will detect the non scan flops in between 2 scan flops. It will detect MCPs also, Suppose we set sequential depth as 3, it will detect MCP with 3 cycles and also non scan flops which are in between scan flops.
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 https://www.e
In which stage of the design flow we get an idea about the false paths and multicycle paths in the design? Which tool will report them? In RTL level, we are left with the logic of the design only and we will have no idea about how the tool will synthesize different paths in the design. The tool will synthesize the design according to it's algorit
I suppose you are using some tool like Dc compiler and you want to specify a multicycle path constraint for a design...right ???
A multicycle path is one where the signal generated by the source need not be sampled at the destination the very next cycle. The destination usually has more than 1 cycle to sample this signal. What kind of constraint do you want?
Hi, suppose we want to create data path of multicycle MIPS processor.our clock frequency is 400MHz and we want to execute every instruction in minimum time.(delay of Controllers and multiplexers is zero) Instructions to be Implemented: addu, addui, and, andi, beq, bne, lw, sw Memory: Address to Read-Data propagation delay: 9 ns Write to Rea
Hi Is DesignWare's multiplier needed to multicycle path? I want to use 3stage multiplier but I don't know about how much it needed clock to result. And should I have to constraint to multicycle 3 depth to here?
Hi,does anyone know how to fix this error?. I'm trying to create multicycle processor using verilog. During the test bench simulation in modelsim, it gives 113073
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
It the responsibility of the designer to communicate it to the synthesis engineer if there are any multicycle paths in the design. The designer is the only person familiar with the design. The synthesis engineer is unaware of the design details. Once the synthesis engineer is aware of multicycle paths, he can form the necessary constraints and use
Hi. I have some question at synthesis. When you have been synthesis, did you always give or receive information like multicycle path -2? I mean when they have getting more bigger design, they are miss or even don't know information for synthesis. So how can you overcome this issue?
Hi, During stuck-at testing, what will happen to false and multicycle paths from the functional logic. Will stuck-at testing take them as faults? How does ATPG tool handle false and multicycle paths?
False path is more restrictive, and then this one has priority over the multicycle path exception. Same idea for set_max_transition, you could not relax with this command, the tool will use the most constrainted value provided (or not) by the liberty or the constraint.
Hi All, What Timing Constraints should be applied to Synchronizers? Should it be False Path? multicycle Path? Max Delay? Etc? Thank you!