d_pwm: Add a hybrid oscillator (analg control in, digital out) with PWM

(pulse width modulation) capability, oscillation frequency is a parameter.

The model has been derived from the d_osc example.

src/xspice/icm/digital/d_pwm/cfunc.mod

@@ -0,0 +1,485 @@
+/*.......1.........2.........3.........4.........5.........6.........7.........8
+================================================================================
+
+FILE d_pwm/cfunc.mod
+
+Public Domain
+
+Georgia Tech Research Corporation
+Atlanta, Georgia 30332
+PROJECT A-8503-405
+The ngspice team
+
+AUTHORS
+
+    24 Jul 1991     Jeffrey P. Murray
+    02 Mar 2022     Holger Vogt
+
+MODIFICATIONS
+
+    23 Aug 1991    Jeffrey P. Murray
+    30 Sep 1991    Jeffrey P. Murray
+
+
+SUMMARY
+
+    This file contains the model-specific routines used to
+    functionally describe the d_pwm code model.
+
+
+INTERFACES
+
+    FILE                 ROUTINE CALLED
+
+    CMmacros.h           cm_message_send();
+
+    CM.c                 void *cm_analog_alloc()
+                         void *cm_analog_get_ptr()
+
+    CMevt.c              void cm_event_queue()
+
+
+REFERENCED FILES
+
+    Inputs from and outputs to ARGS structure.
+
+
+NON-STANDARD FEATURES
+
+    NONE
+
+===============================================================================*/
+
+/*=== INCLUDE FILES ====================*/
+
+#include "d_pwm.h"    /*    ...contains macros & type defns.
+                               for this model.  7/24/91 - JPM */
+
+
+
+/*=== CONSTANTS ========================*/
+
+
+
+
+/*=== MACROS ===========================*/
+
+
+
+
+/*=== LOCAL VARIABLES & TYPEDEFS =======*/
+
+
+
+
+/*=== FUNCTION PROTOTYPE DEFINITIONS ===*/
+
+
+
+
+
+/*==============================================================================
+
+FUNCTION cm_d_pwm()
+
+AUTHORS
+
+    24 Jul 1991     Jeffrey P. Murray
+    02 Mar 2022     Holger Vogt
+
+MODIFICATIONS
+
+    30 Sep 1991     Jeffrey P. Murray
+
+SUMMARY
+
+    This function implements the d_pwm code model.
+
+INTERFACES
+
+    FILE                 ROUTINE CALLED
+
+    CMmacros.h           cm_message_send();
+
+    CM.c                 void *cm_analog_alloc()
+                         void *cm_analog_get_ptr()
+
+    CMevt.c              void cm_event_queue()
+
+RETURNED VALUE
+
+    Returns inputs and outputs via ARGS structure.
+
+GLOBAL VARIABLES
+
+    NONE
+
+NON-STANDARD FEATURES
+
+    NONE
+
+==============================================================================*/
+
+/*=== CM_D_PWM ROUTINE ===*/
+
+/*************************************************************
+*   The following is the model for a duty cycle controlled   *
+*   digital oscillator, derived from the controlled digital  *
+*   oscillator d_osc.                                        *
+*                                                            *
+*   Created 3/02/2022                           H. Vogt      *
+*************************************************************/
+
+/*************************************************************
+*                                                            *
+*                                                            *
+*                          <-----duty_cycle----->            *
+*  I                                                         *
+*  I                      t2               t3                *
+*  I                       \______________/_____             *
+*  I                       |                    |            *
+*  I                 |     |              |     |            *
+*  I                       |                    |            *
+*  I                 |     |              |     |            *
+*  I                       |                    |            *
+*  I                 |     |              |     |            *
+*  I-----------------*-----* - - - - - - - - - -*---------   *
+*                   t1                         t4            *
+*                                                            *
+*                                                            *
+*                     t2 = t1 + rise_delay                   *
+*                     t4 = t3 + fall_delay                   *
+*                                                            *
+*        Note that for the digital model, unlike for the     *
+*    analog "square" model, t1 and t3 are stored and         *
+*    adjusted values, but t2 & t4 are implied by the         *
+*    rise and fall delays of the model, but are otherwise    *
+*    not stored values.                     JPM              *
+*                                                            *
+*************************************************************/
+
+#include <stdlib.h>
+
+void cm_d_pwm(ARGS)
+{
+
+    double           *x,    /* analog input value control array */
+                     *y,    /* frequency array  */
+             cntl_input,    /* control input value  */
+                 *phase,    /* instantaneous phase of the model  */
+             *phase_old,    /* previous phase of the model   */
+                    *t1,    /* pointer to t1 value  */
+                    *t3,    /* pointer to t3 value  */
+              /*time1,*/    /* variable for calculating new time1 value */
+              /*time3,*/    /* variable for calculating new time3 value */
+               dc = 0.5,    /* instantaneous duty cycle value    */
+                 dphase,    /* fractional part into cycle */
+             frequency,     /* frequency value */
+            test_double,    /* testing variable */
+                  slope;    /* slope value...used to extrapolate
+                               freq values past endpoints.  */
+
+
+    int               i,    /* generic loop counter index */
+              cntl_size,    /* control array size         */
+              dc_size;      /* duty cycle array size       */
+
+
+
+
+
+
+    /**** Retrieve frequently used parameters... ****/
+
+    cntl_size = PARAM_SIZE(cntl_array);
+    dc_size = PARAM_SIZE(dc_array);
+    frequency = PARAM(frequency);
+
+
+    /* check and make sure that the control array is the
+       same size as the frequency array */
+
+    if(cntl_size != dc_size){
+        cm_message_send(d_pwm_array_error);
+        return;
+    }
+
+
+    if (INIT) {  /*** Test for INIT == TRUE. If so, allocate storage, etc. ***/
+
+
+        /* Allocate storage for internal variables */
+        cm_analog_alloc(0, sizeof(double));
+        cm_analog_alloc(1, sizeof(double));
+        cm_analog_alloc(2, sizeof(double));
+
+        /* assign internal variables */
+        phase = phase_old = (double *) cm_analog_get_ptr(0,0);
+
+        t1 = (double *) cm_analog_get_ptr(1,0);
+
+        t3 = (double *) cm_analog_get_ptr(2,0);
+
+    }
+
+    else {    /*** This is not an initialization pass...retrieve storage
+                   addresses and calculate new outputs, if required. ***/
+
+
+        /** Retrieve previous values... **/
+
+
+        /* assign internal variables */
+        phase = (double *) cm_analog_get_ptr(0,0);
+        phase_old = (double *) cm_analog_get_ptr(0,1);
+
+        t1 = (double *) cm_analog_get_ptr(1,0);
+
+        t3 = (double *) cm_analog_get_ptr(2,0);
+
+    }
+
+
+
+
+    switch (CALL_TYPE) {
+
+    case ANALOG:    /** analog call **/
+
+        test_double = TIME;
+
+        if ( AC == ANALYSIS ) { /* this model does not function
+                                   in AC analysis mode.         */
+
+            return;
+
+        }
+        else {
+
+            if ( 0.0 == TIME ) { /* DC analysis */
+
+                /* retrieve & normalize phase value */
+                *phase = PARAM(init_phase);
+                if ( 0 > *phase ) {
+                    *phase = *phase + 360.0;
+                }
+                *phase = *phase / 360.0;
+
+
+                /* set phase value to init_phase */
+                *phase_old = *phase;
+
+                /* preset time values to harmless values... */
+                *t1 = -1;
+                *t3 = -1;
+
+
+            }
+
+
+            /* Allocate storage for breakpoint domain & duty cycle range values */
+
+            x = (double *) calloc((size_t) cntl_size, sizeof(double));
+            if (!x) {
+                cm_message_send(d_pwm_allocation_error);
+                return;
+            }
+
+            y = (double *) calloc((size_t) dc_size, sizeof(double));
+            if (!y) {
+                cm_message_send(d_pwm_allocation_error);
+                if(x) free(x);
+                return;
+            }
+
+            /* Retrieve x and y values. */
+            for (i=0; i<cntl_size; i++) {
+                x[i] = PARAM(cntl_array[i]);
+                y[i] = PARAM(dc_array[i]);
+            }
+
+            /* Retrieve cntl_input value. */
+            cntl_input = INPUT(cntl_in);
+
+            /* Determine segment boundaries within which cntl_input resides */
+                        /*** cntl_input below lowest cntl_voltage ***/
+            if (cntl_input <= x[0]) {
+
+                slope = (y[1] - y[0])/(x[1] - x[0]);
+                dc = y[0] + (cntl_input - x[0]) * slope;
+
+            }
+            else
+                /*** cntl_input above highest cntl_voltage ***/
+
+            if (cntl_input >= x[cntl_size-1]) {
+
+                slope = (y[cntl_size-1] - y[cntl_size-2]) /
+                         (x[cntl_size-1] - x[cntl_size-2]);
+                dc = y[cntl_size-1] + (cntl_input - x[cntl_size-1]) * slope;
+
+            }
+            else { /*** cntl_input within bounds of end midpoints...
+                        must determine position progressively & then
+                        calculate required output.                ***/
+
+                for (i=0; i<cntl_size-1; i++) {
+
+                    if ( (cntl_input < x[i+1]) && (cntl_input >= x[i]) ) {
+
+                        /* Interpolate to the correct duty cycle value */
+
+                        dc = ( (cntl_input - x[i]) / (x[i+1] - x[i]) ) *
+                               ( y[i+1]-y[i] ) + y[i];
+                    }
+                }
+            }
+
+            /*** If dc < 0.0, clamp to 0 & issue a warning ***/
+            if ( 0.0 > dc ) {
+                dc = 0;
+//                cm_message_send(d_pwm_negative_dc_error);
+            }
+            /*** If dc > 1.0, clamp to 1 & issue a warning ***/
+            if ( 1.0 < dc ) {
+                dc = 1;
+//                cm_message_send(d_pwm_positive_dc_error);
+            }
+
+
+            /* calculate the instantaneous phase */
+            *phase = *phase_old + frequency * (TIME - T(1));
+
+            /* dphase is the percent into the cycle for
+               the period */
+            dphase = *phase_old - floor(*phase_old);
+
+
+            /* Calculate the time variables and the output value
+               for this iteration */
+
+            if((*t1 <= TIME) && (TIME <= *t3)) { /* output high */
+
+                *t3 = T(1) + (1 - dphase)/frequency;
+
+                if(TIME < *t3) {
+                    cm_event_queue(*t3);
+                }
+
+
+            }
+            else
+
+            if((*t3 <= TIME) && (TIME <= *t1)) { /* output low */
+
+                if(dphase > (1.0 - dc) ) {
+                        dphase = dphase - 1.0;
+                }
+                *t1 = T(1) + ( (1.0 - dc) - dphase)/frequency;
+
+                if(TIME < *t1) {
+
+                    cm_event_queue(*t1);
+
+                }
+            }
+            else {
+
+                if(dphase > (1.0 - dc) ) {
+                    dphase = dphase - 1.0;
+                }
+                *t1 = T(1) + ( (1.0 - dc) - dphase )/frequency;
+
+                if((TIME < *t1) || (T(1) == 0)) {
+                    cm_event_queue(*t1);
+                }
+
+                *t3 = T(1) + (1 - dphase)/frequency;
+
+
+            }
+
+
+
+            if(x) free(x);
+            if(y) free(y);
+
+
+        }
+        break;
+
+
+    case EVENT:    /** discrete call...lots to do **/
+
+
+        test_double = TIME;
+
+        if ( 0.0 == TIME ) { /* DC analysis...preset values,
+                                as appropriate.... */
+
+            /* retrieve & normalize phase value */
+            *phase = PARAM(init_phase);
+            if ( 0 > *phase ) {
+                *phase = *phase + 360.0;
+            }
+            *phase = *phase / 360.0;
+
+
+            /* set phase value to init_phase */
+            *phase_old = *phase;
+
+            /* preset time values to harmless values... */
+            *t1 = -1;
+            *t3 = -1;
+        }
+
+
+
+        /* Calculate the time variables and the output value
+           for this iteration */
+
+        /* Output is always set to STRONG */
+        OUTPUT_STRENGTH(out) = STRONG;
+
+
+
+        if( *t1 == TIME ) { /* rising edge */
+
+            OUTPUT_STATE(out) = ONE;
+            OUTPUT_DELAY(out) = PARAM(rise_delay);
+
+        }
+        else {
+
+            if ( *t3 == TIME ) { /* falling edge */
+
+                OUTPUT_STATE(out) = ZERO;
+                OUTPUT_DELAY(out) = PARAM(fall_delay);
+            }
+
+            else { /* no change in output */
+
+                if ( TIME != 0.0 ) {
+                    OUTPUT_CHANGED(out) = FALSE;
+                }
+
+                if ( (*t1 < TIME) && (TIME < *t3) ) {
+                    OUTPUT_STATE(out) = ONE;
+                }
+                else {
+                    OUTPUT_STATE(out) = ZERO;
+                }
+            }
+        }
+
+        break;
+
+    }
+}
+
+
+
+
+
+
+

src/xspice/icm/digital/d_pwm/d_pwm.h

@@ -0,0 +1,93 @@
+/*.......1.........2.........3.........4.........5.........6.........7.........8
+================================================================================
+
+FILE d_pwm/d_pwm.h
+
+Public Domain
+
+Georgia Tech Research Corporation
+Atlanta, Georgia 30332
+PROJECT A-8503-405
+The ngspice team
+
+AUTHORS                      
+
+    25 Jul 1991     Jeffrey P. Murray
+    02 Mar 2022     Holger Vogt
+
+
+MODIFICATIONS   
+
+    30 Sept 1991    Jeffrey P. Murray
+                                   
+
+SUMMARY
+
+    This file contains the header information for the d_pwm
+    code model.
+
+
+INTERFACES       
+
+    FILE                 ROUTINE CALLED     
+
+    N/A                  N/A
+                         
+
+
+REFERENCED FILES
+
+    N/A
+                     
+
+NON-STANDARD FEATURES
+
+    NONE
+
+===============================================================================*/
+/*
+         Structures, etc. for d_pwm oscillator model.     
+         7/25/90                                     
+         Last Modified 7/25/91               J.P.Murray
+                       3/02/22               H. Vogt         */
+
+/*=======================================================================*/
+
+/*=== INCLUDE FILES =====================================================*/
+                                    
+#include <stdio.h>
+#include <ctype.h>
+#include <math.h>
+#include <string.h>
+
+
+
+
+/*=== CONSTANTS =========================================================*/
+
+
+/****  Error Messages ****/
+char *d_pwm_allocation_error = "\n**** Error ****\nD_PWM: Error allocating VCO block storage \n";
+char *d_pwm_array_error = "\n**** Error ****\nD_PWM: Size of control array different than duty cycle array \n";
+char *d_pwm_negative_dc_error = "\n**** Error ****\nD_PWM: The extrapolated value for duty cycle\nhas been found to be negative... \n Lower duty cycle level has been clamped to 0.0  \n";
+char *d_pwm_positive_dc_error = "\n**** Error ****\nD_PWM: The extrapolated value for duty cycle\nhas been found to be > 1... \n Upper duty cycle level has been clamped to 1.0  \n";
+
+
+
+
+
+
+/*=== MACROS ============================================================*/
+
+
+  
+/*=== LOCAL VARIABLES & TYPEDEFS ========================================*/                         
+
+    
+           
+/*=== FUNCTION PROTOTYPE DEFINITIONS ====================================*/
+
+
+/*=======================================================================*/
+                                    
+

src/xspice/icm/digital/d_pwm/ifspec.ifs

@@ -0,0 +1,77 @@
+/*.......1.........2.........3.........4.........5.........6.........7.........8
+================================================================================
+Public Domain
+
+Georgia Tech Research Corporation
+Atlanta, Georgia 30332
+The ngspice team
+
+
+AUTHORS                      
+
+    30 Sept 1991     Jeffrey P. Murray
+    02 Mar  2022     Holger Vogt
+
+
+SUMMARY
+
+    This file contains the interface specification file for the 
+    hybrid d_pwm code model.
+
+===============================================================================*/
+
+NAME_TABLE:
+
+Spice_Model_Name:      d_pwm
+C_Function_Name:       cm_d_pwm
+Description:           "duty cycle controlled digital oscillator"
+
+
+PORT_TABLE:
+
+Port_Name:           cntl_in            out
+Description:         "control input"    "output"
+Direction:           in                 out
+Default_Type:        v                  d
+Allowed_Types:       [v,vd,i,id]        [d]
+Vector:               no                 no
+Vector_Bounds:        -                  -
+Null_Allowed:        no                 no
+
+
+
+PARAMETER_TABLE:
+
+Parameter_Name:     cntl_array          dc_array    
+Description:        "control array"     "duty cycle array"
+Data_Type:          real                real
+Default_Value:      0.0                 0.5                
+Limits:             -                   [0 1]                    
+Vector:              yes                 yes
+Vector_Bounds:       [2 -]               [2 -]                
+Null_Allowed:       no                  no       
+
+
+PARAMETER_TABLE:
+
+Parameter_Name:     frequency               init_phase
+Description:        "oscillator frequency"  "initial phase of output"
+Data_Type:          real                    real
+Default_Value:      1e6                     0
+Limits:             [1e-6 -]                [-180.0 +360.0]
+Vector:              no                      no
+Vector_Bounds:       -                       -
+Null_Allowed:       yes                     yes 
+
+
+PARAMETER_TABLE:
+
+Parameter_Name:     rise_delay              fall_delay
+Description:        "rise delay"            "fall delay"
+Data_Type:          real                    real
+Default_Value:      1e-9                    1e-9
+Limits:             [0 -]                   [0 -]
+Vector:              no                      no
+Vector_Bounds:       -                       -
+Null_Allowed:       yes                     yes 
+

src/xspice/icm/digital/modpath.lst

@@ -17,6 +17,7 @@ d_or
 d_osc
 d_pulldown
 d_pullup
+d_pwm
 d_ram
 d_source
 d_srff

visualc/xspice/digital.vcxproj

@@ -276,6 +276,10 @@
       <AdditionalIncludeDirectories>..\..\src\xspice\%(RelativeDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
     <ClCompile Include="icm\digital\d_pullup\d_pullup-ifspec.c" />
+    <ClCompile Include="icm\digital\d_pwm\d_pwm-cfunc.c">
+      <AdditionalIncludeDirectories>..\..\src\xspice\%(RelativeDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+    </ClCompile>
+    <ClCompile Include="icm\digital\d_pwm\d_pwm-ifspec.c" />
     <ClCompile Include="icm\digital\d_ram\d_ram-cfunc.c">
       <AdditionalIncludeDirectories>..\..\src\xspice\%(RelativeDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
@@ -353,6 +357,8 @@
     <None Include="..\..\src\xspice\icm\digital\d_pulldown\ifspec.ifs" />
     <None Include="..\..\src\xspice\icm\digital\d_pullup\cfunc.mod" />
     <None Include="..\..\src\xspice\icm\digital\d_pullup\ifspec.ifs" />
+    <None Include="..\..\src\xspice\icm\digital\d_pwm\cfunc.mod" />
+    <None Include="..\..\src\xspice\icm\digital\d_pwm\ifspec.ifs" />
     <None Include="..\..\src\xspice\icm\digital\d_ram\cfunc.mod" />
     <None Include="..\..\src\xspice\icm\digital\d_ram\ifspec.ifs" />
     <None Include="..\..\src\xspice\icm\digital\d_source\cfunc.mod" />