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Explorer
Explorer
4,258 Views
Registered: ‎12-29-2008

Synthesis warning:::::

Hi,

I am getting following warning while doing synthesis : Could any one please tell me the impact of this ...

 

WARNING:PhysDesignRules:372 - Gated clock. Clock net
   DCM_AUTOCALIBRATION_clock_generator_0/clock_generator_0/Using_DCM0.DCM0_INST/
   DCM_INST/Using_DCM_ADV.DCM_ADV_INST/clock_generator_0/clock_generator_0/Using
   _DCM0.DCM0_INST/DCM_INST/Using_DCM_ADV.DCM_ADV_INST/cd/CLK<4> is sourced by a
   combinatorial pin. This is not good design practice. Use the CE pin to
   control the loading of data into the flip-flop.

regards

Krish 

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3 Replies
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Observer
Observer
4,250 Views
Registered: ‎09-07-2009

Re: Synthesis warning:::::

Hey,

 

you will get such warnings when you are not using the special clock inputs. For example if you have signals one your board connected to standart io pins and you are using such a signal as a clock in your design (iosignal='1' and iosignal' event) you will get these warning. It would be better to wire these signal to a special clock pin but it is not necessary.

 

But i don't know what happens with your timing maybe std. io pins aren't so fast as special clock pins but i don't know. It would be nice if an expert can give a statement to this thread.

 

nice synthesis

 

manu

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Historian
Historian
4,245 Views
Registered: ‎02-25-2008

Re: Synthesis warning:::::


onkarkk1 wrote:

Hi,

I am getting following warning while doing synthesis : Could any one please tell me the impact of this ...

 

WARNING:PhysDesignRules:372 - Gated clock. Clock net
   DCM_AUTOCALIBRATION_clock_generator_0/clock_generator_0/Using_DCM0.DCM0_INST/
   DCM_INST/Using_DCM_ADV.DCM_ADV_INST/clock_generator_0/clock_generator_0/Using
   _DCM0.DCM0_INST/DCM_INST/Using_DCM_ADV.DCM_ADV_INST/cd/CLK<4> is sourced by a
   combinatorial pin. This is not good design practice. Use the CE pin to
   control the loading of data into the flip-flop.

regards

Krish 


Heh. The tools automagically insert this autocalibration stuff whenever you use a V4 DCM. Unfortunately, this throws a boatload of warnings at you.

 

It's not your fault. It's the tools. There's no way to avoid these errors, but you can ignore them. Open a Webcase and complain. It won't solve anything but at least you'll register a valid complaint with the mothership.

----------------------------Yes, I do this for a living.
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Explorer
Explorer
4,227 Views
Registered: ‎12-29-2008

Re: Synthesis warning:::::

Fine i will do that..

 

regards

Krish

 

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