Hi,

 Recently I am converting all my previous macro-models from vlog-a to vlog-ams, and
also migrate from spectre-vlog to AMS. I found that some terminal with "voltage" discipline
can be used in spectre/spectre-vlog simulation, but I have to to change to "electrical"
discipline if I want to use them in AMS simulator.

So why these disciplines make such difference between old mixed-mode simulator and
AMS designer? since I am pretty sure that no current will flow in to/out from
the terminals.

Hi NG!

I have had a related problem:

Does Spectre support voltage as a signal-flow quantity? I was using it for modeling expecting that it would reduce the dimension of the system. As I can see from the logfile of Spectre, the number of equations is not reduced by changing from electrical to voltage.

Does anyone have an explanation for this? What is the benefit of using the signal-flow quantity (instead of electrical) then?

Cheers
Daniel

//
// Design File for: (VFS_AMS_PHY180_sims cds_globals test_vco_config)
//
// Verilog-AMS cds_globals module for top-level cell:
//    VFS_AMS_PHY180_sims/test_vco.
// Generated by ADE.
// Cadence Design Systems, Inc.

// This is an autoGenerated file, any changes done to this file may get lost.

`include "disciplines.vams"
`include "userDisciplines.vams"

module cds_globals;

// Global Signals
  electrical \gnd! ;
  ground \gnd! ;

// Design Variables

endmodule

// This is the Cadence AMS Designer(R) analog simulation control file.
// It specifies the options and analyses for the Spectre and UltraSim
// analog solvers. To facilitate using the file outside of
// Cadence environments, the file includes options for both solvers.

// Many options between Spectre and UltraSim share similar
// names or semantics but the values used are different
// depending on solver. For this reason, these particular
// options are solver specific.


simulator lang=spectre


// The following options are used by both analog solvers.

commonOptions1 options temp=27
commonOptions2 options tnom=27
commonOptions3 options scale=1.0
commonOptions4 options scalem=1.0


// The following options are used by only the Spectre solver.
// The UltraSim solver ignores these options.

*--------------------------------------------------------*
* Spectre Solver Options
*--------------------------------------------------------*
spectreOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 gmin=1e-12
+   rforce=1 maxnotes=5 maxwarns=5 digits=5 pivrel=1e-3


// The following options are used only by the UltraSim solver.
// The Spectre solver sees the "*ultrasim: " prefix and
// ignores these options.

*--------------------------------------------------------*
* UltraSim Solver Options
*--------------------------------------------------------*
*ultrasim: .usim_opt output_upper=0 ade=1 wf_spectre_syntax=1

// The following option statements specify the Transient analysis.
// Some of the parameters are used by both solvers. The subset
// noted below explains what is supported by each solver.

tran tran stop=10u save=none write="spectre.ic" writefinal="spectre.fc"
//  The following parameters are used only by the Spectre solver.
//  They are present in the SPECTRE TRANSIENT PARAMETERS section
//  of ADE transient analysis GUI. The UltraSim solver ignores
//  these parameters.
+   maxiters=5 annotate=status

// The following info statement, which is used by both solvers,
// returns the final operating point from the last timepoint in the
// transient analysis. Writing out the operating point can result in a
// large operating point results file, especially when using UltraSim on
// large designs.  For this reason you can enable/disable this analysis
// for the UltraSim solver by using the 'Save Final Op Pt' option,
// in the ULTRASIM TRANSIENT PARAMETERS section of ADE transient
// analysis GUI.

finalTimeOP info what=oppoint where=rawfile

// The following statements, which are used by both solvers, save
// internal simulation data. These "analyses" can be turned
// OFF from the ADE save options GUI.

modelParameter info what=models where=rawfile
element info what=inst where=rawfile
outputParameter info what=output where=rawfile

# This is the NC-SIM(R) probe command file
# used in the AMS-ADE integration.


#
# Database settings
#
database -open ams_database -into ../psf -default

#
# Probe settings
#