VerilogA: analysis function will not take a string variable

There's the built-in component switch in spectre which does this already. Can you use that instead? If using in Virtuoso, there is the sp[1234]tswitch components in analogLib which netlist to the spectre switch component.

The approach above won't work because the analysis function expects a literal constant string (this is clear from the Verilog-AMS standard LRM too).

Regards,

Andrew

Thank you for your reply.

The reason I am not using the component provided in analogLib is because it allows you to choose only among DC, AC, tran, IC. Now suppose in a testbench I want the switch to be open only for sp analysis and closed for any other analysis, then, correct me if I am wrong, the sp[1234]tswitch will not do the job, right?

Regarding the literal constant string: it is not clear to me when I write string ana ="something"; now isn't ana a string? And so, what is the difference between this string and such expected literal constant string? (even when it is not a parameter it won't work).

I've had a look at the verilog AMS LRM, and from there paragraph 3.3 it looks to me like "something" being a literal string, when assigned to a variable var="something" then var becomes a string, which is something different than a literal constant string. So what could be the workaround to have a switch with a parameter where I choose the target analysis? (otherwise I should create a cell for each different combination of analyses that I want it to be selective to).

I believe that "ac" will work for sp analysis too on the switch component (I didn't check to be sure though). It would be very strange to only want a setting for a model in a specific analysis (i.e. "sp" and not "ac"), but maybe you want this for some reason.

Anyway, the issue is not that. you can't have string parameters - of course you can. The issue is that the analysis function only supports literal strings. From A.8.2 Function Calls:

analysis_function_call ::= analysis ( " analysis_identifier " { , " analysis_identifier " } )

Notice that the analysis_identifier are in quotes. It doesn't support parameters or variables with the analysis. This is probably because it needs to be known quite earlier for compilation/optimisation purposes. The message you are getting is indicating that it needs a constant string expression as the argument to analysis. Passing a parameter would need this to be resolved differently on each instance of the model, for example.

Andrew

Alright, so it I understand there is not really a workaround for this, but creating one cell for each specific set of analyses I want my switch to be selective to.

Thank you for your answers