how to use "deparam" statement

[seektm@yahoo.com.cn]

is it used in IP resue?

 

In general, the use of defparam is a bad practice. If you want to
create a parameterized design for reuse, it is cleaner to override the
parameters on the module instantiation instead. One common way that
defparam is used is to instantiate a module, followed immediately by
defparams to override the module parameter values. In this case, the
overrides could have been put directly on the instantiation instead.

Sometimes it is desired to modify parameter values buried deep down in
the design, without having to pass values through the intermediate
hierarchy. In these cases, an argument could be made for the use of
defparam.

 

[Ajeetha]

IIRC, synthesis doesn't support/prefer defparams hence another reason
to avoid it, use Steve's suggestion instead. Especially in IPs - please
avoid.

HTH
Ajeetha
www.noveldv.com

 

[Andy Peters]

Ajeetha wrote:

IIRC, synthesis doesn't support/prefer defparams hence another reason
to avoid it, use Steve's suggestion instead. Especially in IPs - please
avoid.

RTFM. Some synthesis tools DO support defparams -- Precision does.
gotta watch out which tools don't let you override defparams from the
command line (yes, XST, I'm talking about YOU).

defparams are not preferred, though.

-a

 

[seektm@yahoo.com.cn]

thanks for your explanations.