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Set initial value for inputs/outputs for verilog cells in mixed-signal simulation (XCELIUM UNL)

patschouly

Hello,

I'm simulating mixed-signal designs with AMS-UNL. I think my setup is correct, up to now everything is working as expected. However, I'm simulating a prescaler, where I don't care about the phase of the signal. Therefore, the used flip-flops don't have a reset input. This causes the outputs of the prescaler to be not specified. The log tells me:

INFO (VLOGNET-67): The initial state of stimulus of all inout pins is set to "0". To get the
initial state of "z" of all inout pins, set hnlVerilogIOInitStimulusStr =
"z" either in CIW or the .simrc file.

I did that (in the CIW) and it did not change anything. Does the variable has to be set in a certain way? I just did hnlVerilogIOInitStimulusStr = "O" and the log tells me this worked. However, it does not solve my problem. How can I set the initial values of all flip flops to zero/one?

Thank you, kind regards,

Patrick

  • To add a little more to this:

    I also tried initial conditions, similar to a pure analog simulation, which did not change anything. I found that xrun understands options such as -initreg0 and -initmem0, which seem like the appropriate options. Still, adding these to the run did not change anything.

    Another option for me would be to add an initial-block with a force and release statement. However, I have no clue on how I would be doing that. Where would I have to add such statements?

    I'm at loss here, I'd very happy if anyone could shed some light on this topic.

    Kind regards,

    Patrick

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