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Using Print in Spectre

TimCoyle

Hi,

I am trying to use the print command in Spectre for a transient analysis to save the voltage of an output node to an external file. I would like for the time step to be used in the print results so for example if my time step=0.1ns than the node voltage printed in the external file will have a time step of 0.1ns. 

Here's what I have for syntax:

TranName1 tran start=0 stop=7ns step=.0035ns

PRINT RWF_GND= v(rwf_gnd), FWF_GND = v(fwf_gnd), RWF_VCC= v(rwf_vcc), FWF_VCC= v(fwf_vcc), name=allvttyp to="all_vt_typ.lis"

This is acutally an HSPICE netlist that I am running in spice compatible mode and I did try to use the following HSPICE syntax to save the output voltage nodes to a .print file but again I could not get the correct time step in the output data:

.tran 0.0035ns 7.0ns START=10ns

.PRINT TRAN
+ RWF_GND      = v(rwf_gnd)
+ FWF_GND      = v(fwf_gnd)
+ RWF_VCC      = v(rwf_vcc)
+ FWF_VCC      = v(fwf_vcc)

If anyone has any insight on using either method to get the output data with the correct time step let me know!

 

Best,

 Tim

 

  • Hi Tim,

    Can you try using the strobeperiod .

    You can use it as :

    tran1 tran stop=7ns strobeperiod=0.0035ns 

    Best Regards,
    Sunil

  • Hi Tim,

    strobeperiod is not what you want to use.   Instead use the printstep option described in the Solution 11612474.  You will want to use MMSIM 7.1.1 or later versions of Spectre for this to work properly.

    How to print .TRAN simulation results with equal time steps in .print file.

    http://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin:ViewSolution;solutionNumber=11612474

     


    best regards,

     Tawna

     

  • Hi Tawna,

    Thanks for the information on using printstep - that solved my problem! 

    I am getting some strange formatting results in my .print file though. It doesn't seem that my .options are being carried over to enforce the correct number of significant digits. 

    Here are my .options I am using:

    .options printstep=yes brief ingold numdgt=10 co=132 acct=0 nowarn rmax=0.5

    Here is what a a couple of lines of results from the .print looks like:

    3.465e-10   1.6288430312 0.021156968836   3.2788430312   1.6711569688
        3.5e-10   1.64108039420.0089196057964    3.2910803942   1.6589196058

    Shouldn't these all be limited to 10 significant digits? You can see that for one of the print lines the number has so many digits it is running into the first printed number making it all look like one number.

    I really can't reduce the number of significant digits below 10 or I will lose accuracy with my real data since the resolution needs to be very fine.

    Any suggestions?

     

    Thanks,

    Tim

     

  •  Hi Tim,

    Would you please file a Service Request via support.cadence.com ?  I believe that we will need to file either an enhancement or bug CCR on this. 

    best regards,

    Tawna

  •  Hi Tawna,

    I think I actually figured it out. I had the .option ingold card and I think by default ingold is set to 1. When I set it to 2 than I appear to get the correct formatting. I can't quite remember the difference between the 1 and 2 setting but I think one of them is supposed to be a fixed scientific notation format. 

     Best,

    Tim

     

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