From: Adam Krolnik (adamk@cyrix.com)
Date: Thu May 21 1998 - 03:36:55 PDT
Behavioral Task Force - Errata Submission
Assigned Errata Number: BE75
Errata Name (Description): Unspecified abilities on instantiation
of modules.
Date Submitted: 980413
Requestor: Adam Krolnik
Status: Submitted (priority not yet assigned)
Errors found in the Verilog LRM (IEEE 1364-1995).
Details:
I don't see anywhere in the BNF how you can specify the drive strength for
a plain module instantiation.
Both XL and VCS accept this, yet it isn't documented anywhere.
What should be done with this? Erratta?
Adam Krolnik
Verification Engineer
Cyrix - NSM.
Richardson TX. 75085
<p>--------------------------------------------------
module top;
wire y,a,b;
// Hey, I get to specify strengths! Useless!!
adam (weak0, strong1) #(5,5) n2(y,a,b);
endmodule
<p>module adam( Y, A, B);
parameter tr = 1;
parameter tf = 1;
parameter m = 1;
input A, B;
output Y;
<p>initial begin
$display("The parameters are %0d %0d %0d.", tr,tf, m);
end
// Here are valid drive strength parameters!!
nor (strong0, strong1) #( tr, tf) G1(Y, A, B);
endmodule
<p>Proposal:
The strength information has no effect on the outputs of a non primitive module.
Unless we want to allow this for consistency with primitives, but no functional
effect, I recommend no changes.
[We could add text to specifically indicate strength specification is not allowed on
module instantiations.]
<p><p> Adam Krolnik
Verification Engineer
Cyrix - NSM.
Richardson TX. 75085
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