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Compiler Error of Verilog-A in Cadence-$dist_norm (Read 98 times)

littlekoala

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Compiler Error of Verilog-A in Cadence-$dist_norm
Aug 30^th, 2006, 9:22pm

Hi, there,

I am trying to model and simulate PLL jitter with the voltage-domain method introduced in Kundert's paper on the designer-guide website.

But I get a compiler error from the Cadence Verilog-A compiler, which says that the system function $dist_normal can not be included in the analog block. The original error message is as follows:

[AMS semcheck]: Error # SEM741: Digital or unknown system function '$dist_normal' found in analog block.

The tool is Cadence ICFB Version 5.1.0.

Can anybody help me out with this problm?

Thank you very much.

Littlekoala

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Ken Kundert Global Moderator Offline Posts: 2384 Silicon Valley	Re: Compiler Error of Verilog-A in Cadence-$dist_n Reply #1 - Aug 30^th, 2006, 10:22pm Use $rdist_normal(). $dist_nomal() returns an integer and can only be used in a digital context, $rdist_normal() returns a real and can only be used in an analog context. -Ken
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jbdavid

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Re: Compiler Error of Verilog-A in Cadence-$dist_n
Reply #2 - Aug 30^th, 2006, 10:42pm

I can't find any reference to $dist_normal in the 2.2 version of the LRM..
may be you can talk Ken into updating his papers to use $rdist_normal which is found..
$dist_normal existed in the Verilog spec first and the verilog-A used with spectre ALSO has to work with AMS designer which conforms to the 2.2 spec (mostly)..
jonathan

jbdavid
Mixed Signal Design Verification

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Ken Kundert

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Re: Compiler Error of Verilog-A in Cadence-$dist_n
Reply #3 - Aug 30^th, 2006, 11:13pm

$dist_normal() was the name used by the standard some time ago, but then it was changed to $rdist_normal() when it was discovered that the analog version returned a real and the digital version returned an integer.

I have updated my paper to use $rdist_normal().

Thanks for pointing out this issue.

-Ken

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