Xilinx timing viloations

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Hi all,

I am facing timing violations in my FPGA with Max frequency 125 Mhz(Set
up viloations).
What are the steps to be taken to meet the frequency other than doing a
pipeline in RTL.
I am using Xilinx FPGA's.

regards


Re: Xilinx timing viloations
Prav,
The approach is very dependent of the root cause.
you have to investigate where your time budget is spent, logic or routing
if is on logic try to reduce the number of logic levels, pipeline,
re-balance registers, etc.
if is on routing try to floor plan, use area constraints, different
switches in map/par etc.

Aurash

prav wrote:
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Re: Xilinx timing viloations
Hi austin,

Generally what is the budget we give for Logic and Routing  delays
respectively?

Regards,
Prav
Aurelian Lazarut wrote:
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Re: Xilinx timing viloations

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Prav,
the budget is your clock period minus setup and hold (assuming SDR)

Aurash
 

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Re: Xilinx timing viloations
The general rule for Xilinx devices (others may be similar) is 50%
routing, 50% logic.  If you're 70% routing, chances are the place &
route can give better results.  If you have 43% routing, there's a
strong chance you won't get better results, at least easily.

prav wrote:
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Re: Xilinx timing viloations
Hi Aurelian ,

What do you mean by re-balance registers??

Regards,
Prav


Aurelian Lazarut wrote:
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Re: Xilinx timing viloations
If you try to perform something too "complex" in your 8 ns, you have to
change the complexity.  Often the problem is that logic has a larger number
of logic levels than the application requires.  Find the critical path,
figure out if you need 12 levels of logic - if there's another way to
produce the same result in fewer logic levels, do it.  Often the FPGA you
target has advanced silicon features that can speed up the implementation if
you know it's there and can code to use it.  Pipelining is often the best
approach, registering parts of the slow path in the previos cycle.

I can't make a baby in 4.5 months.  Is there a way to meet my deadline
without using two women?


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Re: Xilinx timing viloations

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of course it is, just make a baby with each, and we can find a marketing
guy to say that you have 2 childrens in 9 months equals to 4.5 months on
average / baby
Aurash

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