Toggle Coverage through Functional Coverage

Question

I know that Code Coverage is the right way to do toggle coverage. Doing that through Functional Coverage is a long stretch. But, for the sake of argument, I want to select a few signals and do toggle coverage through functional coverage. Will the following work?

bit[7:0] adr1;

covergroup gc @(posedge clk);
ac: coverpoint adr1
{
bins ar1 = (1'b0 => 1'b1 || 1'b1 => 1'b0);
}
endgroup

gc gcInst = new;

Thanks.

Answer 1

dave_59

Forum Moderator

10017 posts

May 13, 2020 at 1:09 pm

In reply to a72:

That gets interpreted as

bins ar1 = (1'b0 => (1'b1 || 1'b1) => 1'b0);
// resolves to
bins ar1 = (8'h00 => 8'h01 => 8'h00);

Which is probably not what you are expecting. See https://verificationacademy.com/forums/systemverilog/bitwise-toggle-coverage-bitvector#reply-89793

— Dave Rich, Verification Architect, Siemens EDA

Answer 2

a72

Full Access

27 posts

May 13, 2020 at 1:31 pm

In reply to dave_59:

Thanks Dave. I looked at the link you provided. I see the following:

bins tr[] = (1=> 0,0 => 1 ;}

So, is that the solution?

Answer 3

dave_59

Forum Moderator

10017 posts

May 13, 2020 at 1:41 pm

In reply to a72:

You have to create an array of covergroups instances, one for each bit.

— Dave Rich, Verification Architect, Siemens EDA

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