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-   -   Declaring an output as 'not connected' (http://www.fpgacentral.com/group/showthread.php?t=45481)

Joe 05-27-2006 12:24 AM

Declaring an output as 'not connected'
 
When I instantiate a module and leave one of its output non connected,
I get a warning complaining that the output was left open (I am using
Xilinx ISE 8.1i).

Is there a way (or a trick) to declare in Verilog that a certain output
port is intentionally not connected? (and by that, avoiding the warning
message).

Thanks,

Joe


unfrostedpoptart 05-27-2006 05:29 AM

Re: Declaring an output as 'not connected'
 

Joe wrote:
> When I instantiate a module and leave one of its output non connected,
> I get a warning complaining that the output was left open (I am using
> Xilinx ISE 8.1i).
>
> Is there a way (or a trick) to declare in Verilog that a certain output
> port is intentionally not connected? (and by that, avoiding the warning
> message).


This is tool-specific: there's no answer that will work with
everything. ISE, since 7.1, has had very extensive warning/error
filtering. Look at the docs to see how to use it.

David


[email protected] 05-29-2006 06:47 AM

Re: Declaring an output as 'not connected'
 
Joe wrote:
> When I instantiate a module and leave one of its output non connected,
> I get a warning complaining that the output was left open (I am using
> Xilinx ISE 8.1i).
>
> Is there a way (or a trick) to declare in Verilog that a certain output
> port is intentionally not connected? (and by that, avoiding the warning
> message).
>
> Thanks,
>
> Joe



Reply : Ramakrishna
It is obvious that any simulater will flag a warning message if any of
the
o/p is kept open(i.e., output is floating).

You have an option for filtering the Messages. for example: if you are
using
ncverilog as a simulator then you need to pass the filter constraint
throgh the
Command line like +nowarn< argument >, here argument is the header of
the
meassge (warning).

ok,
bye
RK



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