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MDL Autostop Using cross and freq Functions

baltacican87

Hello,

I am using Virtuoso version IC6.1.7.

I would like to termiante a transient simulation on an event using autostop with MDL option. My circuit is a 5-stage static inverter ring oscillator. I provide a ramp on vdd and modulate the output frequency at node vout. The frequency rises from ~1GHz to ~2GHz during the transient simulation and I can observe this using the calculator function freq. In my MDL file, create an event which is triggered when the frequency crosses 1.5GHz:

alias measurement tran_autostop {
export real Tcross
run tran
Tcross = cross( sig=freq(sig=V(vout), thresh=0.5, dir='rise), dir='rise, n=1, thresh=1500000000.0 )
}
run tran_autostop

However, the simulation does not stop. What do I need to do to have the simulation stopped when this event (frequency's crossing a threshold) is triggered?

Many thanks in advance.

Best regards,

Can

Parents
  • Andrew Beckett

    Hi Can,

    From the documentation, only a limited number of functions (particularly things like deltax and delay) that identify particular events can trigger auto-stop. The challenge with the approach  you are taking is that normally freq runs at the end of the simulation rather than continuously during the simulation.

    I'm not sure there's an alternative way of doing this using autostop (I wondered about using deltax but that normally triggers auto-stop as soon as the delta has been measured, not when the delta is in a certain range). So this would need an enhancement request via customer support.

    Regards,

    Andrew

Reply
  • Andrew Beckett

    Hi Can,

    From the documentation, only a limited number of functions (particularly things like deltax and delay) that identify particular events can trigger auto-stop. The challenge with the approach  you are taking is that normally freq runs at the end of the simulation rather than continuously during the simulation.

    I'm not sure there's an alternative way of doing this using autostop (I wondered about using deltax but that normally triggers auto-stop as soon as the delta has been measured, not when the delta is in a certain range). So this would need an enhancement request via customer support.

    Regards,

    Andrew

Children
  • baltacican87
    in reply to Andrew Beckett

    Hi Andrew,

    Many thanks for your explanations. I didn't know that some of the functions are evaluated at the end of the simulation.

    Best regards,

    Can

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