The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Measurements >> Other Measurements >> Passing 'errpreset' paramter in MDL
https://designers-guide.org/forum/YaBB.pl?num=1167816404

Message started by topquark on Jan 3^rd, 2007, 1:26am

Title: Passing 'errpreset' paramter in MDL
Post by topquark on Jan 3^rd, 2007, 1:26am

Hi folks!

I wrote a simple MDL script for a tran analysis, but was unable to pass the accuracy parameter 'errpreset'.
The log shows that it always takes the default (=moderate)
I want it to be changed to 'conservative' during run.
The analysis line-
run tran(stop=15us, maxstep=1ns)

doesn't seem to accept errpreset as an argument and errors out.

The help documentation doesn't show how to do this, it just shows how to pass other numeric parameters like
transtop, step etc..

Anybody got an idea?
Thanks
Gau

Title: Re: Passing 'errpreset' paramter in MDL
Post by ACWWong on Jan 3^rd, 2007, 5:43am

The way round this would be to use the run command to call a named rather than primitive (tran, ac, dc etc.) analyses. That way you can add the errpresent setting in the netlist.

Title: Re: Passing 'errpreset' paramter in MDL
Post by John O Donovan on Jan 3^rd, 2007, 9:16am

Hi,

The following should work

Code:

run tran(stop=15us, errpreset='conservative, maxstep=1ns)

I would remove the maxstep paramter though. It generally has no impact on simulation results in Spectre other than slow down simulation, if given a very small value. If you are using threshold type functions (cross, deltax, risetime, ... ), Spectre will place timepoints automatically at the crossing points. If you require fixed timesteps for FFT's then use a z domain controlled source, or strobing parameters.

Regards,
John

Title: Re: Passing 'errpreset' paramter in MDL
Post by topquark on Jan 4^th, 2007, 12:27am

Hi John!

Thanks for supplying that essential apostrophe " ' "
I've got my code working right away..
I was wondering if maxstep affects the 'errpreset' or the latter overrides the former? ::)
Ref: www.designers-guide.org/Forum/YaBB.pl?num=1162459212

Regards,
Gau

Title: Re: Passing 'errpreset' paramter in MDL
Post by Ken Kundert on Jan 4^th, 2007, 8:46am

The 'preset' in errpreset is meant to imply that it takes effect before processing the remaining parameters. In otherwords, errpreset effectively adjusts the defaults of the other parameters according to the mood of the user. As such, any values that you specify for parameters affected by errpreset will take precedence.

-Ken