Interim version of inertial delay for tristate buffer.

This does not handle three-way or mixed transitions.

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

@@ -8,37 +8,30 @@ Public Domain
 Georgia Tech Research Corporation
 Atlanta, Georgia 30332
 PROJECT A-8503-405
-               
 
-AUTHORS                      
+AUTHORS
 
     18 Nov 1991     Jeffrey P. Murray
 
-
-MODIFICATIONS   
+MODIFICATIONS
 
     26 Nov 1991    Jeffrey P. Murray
-                                   
 
 SUMMARY
 
     This file contains the functional description of the d_tristate
     code model.
 
+INTERFACES
 
-INTERFACES       
-
-    FILE                 ROUTINE CALLED     
+    FILE                 ROUTINE CALLED
 
     CMevt.c              void *cm_event_alloc()
                          void *cm_event_get_ptr()
-                         
-
 
 REFERENCED FILES
 
     Inputs from and outputs to ARGS structure.
-                     
 
 NON-STANDARD FEATURES
 
@@ -48,39 +41,30 @@ NON-STANDARD FEATURES
 
 /*=== INCLUDE FILES ====================*/
 
-
-                                      
+#include "ngspice/inertial.h"
 
 /*=== CONSTANTS ========================*/
 
 
-
-
 /*=== MACROS ===========================*/
 
 
+/*=== LOCAL VARIABLES & TYPEDEFS =======*/
 
-  
-/*=== LOCAL VARIABLES & TYPEDEFS =======*/                         
 
-
-    
-           
 /*=== FUNCTION PROTOTYPE DEFINITIONS ===*/
 
 
 
-
-                   
 /*==============================================================================
 
 FUNCTION cm_d_tristate()
 
-AUTHORS                      
+AUTHORS
 
     18 Nov 1991     Jeffrey P. Murray
 
-MODIFICATIONS   
+MODIFICATIONS
 
     26 Nov 1991     Jeffrey P. Murray
 
@@ -88,9 +72,9 @@ SUMMARY
 
     This function implements the d_tristate code model.
 
-INTERFACES       
+INTERFACES
 
-    FILE                 ROUTINE CALLED     
+    FILE                 ROUTINE CALLED
 
     CMevt.c              void *cm_event_alloc()
                          void *cm_event_get_ptr()
@@ -100,7 +84,7 @@ RETURNED VALUE
     Returns inputs and outputs via ARGS structure.
 
 GLOBAL VARIABLES
-    
+
     NONE
 
 NON-STANDARD FEATURES
@@ -123,43 +107,101 @@ NON-STANDARD FEATURES
 *   Last Modified 11/26/91                      *
 ************************************************/
 
-
 void cm_d_tristate(ARGS) 
 {
-    int   enable;    /* holding variable for enable input */
-
-
+    Digital_t          *out;
+    Digital_State_t     val, enable;
+    Digital_Strength_t  str;
+    struct idata       *idp;
+
+    if (INIT) {  /* initial pass */ 
+        /* define input loading... */
+        LOAD(in) = PARAM(input_load);
+        LOAD(enable) = PARAM(enable_load);
+        OUTPUT_DELAY(out) = PARAM(delay);
+
+        /* allocate storage for the previous output. */
+
+        cm_event_alloc(0, sizeof (Digital_t));
+        out = (Digital_t *)cm_event_get_ptr(0, 0);
+        out->state = (Digital_State_t)(UNKNOWN + 1); // Force initial output.
+
+        /* Inertial delay? */
+
+        STATIC_VAR(is_inertial) =
+            cm_is_inertial(PARAM_NULL(inertial_delay) ? Not_set :
+                         PARAM(inertial_delay));
+        if (STATIC_VAR(is_inertial)) {
+            /* Allocate storage for event time. */
+
+            cm_event_alloc(1, 2 * sizeof (struct idata));
+            idp = (struct idata *)cm_event_get_ptr(1, 0);
+            idp[1].when = idp[0].when = -1.0;
+        }
+
+        /* Prepare initial output. */
+
+        out = (Digital_t *)cm_event_get_ptr(0, 0);
+        out->state = (Digital_State_t)(UNKNOWN + 1); // Force initial output.
+    } else {
+        out = (Digital_t *)cm_event_get_ptr(0, 0);
+    }
 
     /* Retrieve input values and static variables */
-    enable = INPUT_STATE(enable);
-
-    OUTPUT_STATE(out) = INPUT_STATE(in);
-    OUTPUT_DELAY(out) = PARAM(delay);
-
-
-    /* define input loading... */
-    LOAD(in) = PARAM(input_load);
-    LOAD(enable) = PARAM(enable_load);
-
-
 
+    val = INPUT_STATE(in);
 
+    enable = INPUT_STATE(enable);
     if (ZERO == enable) {
-
-        OUTPUT_STRENGTH(out) = HI_IMPEDANCE;
-
+        str = HI_IMPEDANCE;
+    } else if (UNKNOWN == enable) {
+        str = UNDETERMINED;
+    } else {
+        str = STRONG;
     }
-    else 
-    if (UNKNOWN == enable) {
-
-        OUTPUT_STRENGTH(out) = UNDETERMINED;
-
-    }
-    else {
-    
-        OUTPUT_STRENGTH(out) = STRONG;
 
+    if (val == out->state && str == out->strength) {
+        OUTPUT_CHANGED(out) = FALSE;
+    } else {
+        if (STATIC_VAR(is_inertial) && ANALYSIS == TRANSIENT) {
+            int           d_cancel, s_cancel;
+
+            idp = (struct idata *)cm_event_get_ptr(1, 0);
+            d_cancel = (idp[0].when > TIME && val == idp[0].prev);
+            s_cancel = (idp[1].when > TIME &&
+                        str == (Digital_Strength_t)idp[1].prev);
+            if ((d_cancel && s_cancel) ||
+                (d_cancel && str == out->strength && TIME >= idp[1].when) ||
+                (s_cancel && val == out->state && TIME >= idp[0].when)) {
+                double when;
+
+                /* Changing back: override pending change. */
+
+                when =  d_cancel ? idp[0].when : idp[1].when;
+                if (s_cancel && when > idp[1].when)
+                    when = idp[1].when;
+
+                OUTPUT_DELAY(out) = (when - TIME) / 2.0; // Override
+                idp[1].when = idp[0].when = -1.0;
+            } else {
+                /* Normal transition, or third value during delay,
+                 * or needs cancel followed by restore of
+                 * the other component (fudge).
+                 */
+
+                OUTPUT_DELAY(out) = PARAM(delay);
+                if (val != out->state) {
+                    idp[0].prev = out->state;
+                    idp[0].when = TIME + OUTPUT_DELAY(out);
+                }
+                if (str != out->strength) {
+                    idp[1].prev = (Digital_State_t)out->strength;
+                    idp[1].when = TIME + OUTPUT_DELAY(out);
+                }
+            }
+        }
+	out->state = val;
+	out->strength = str;
+	*(Digital_t *)OUTPUT(out) = *out;
     }
 }
- 
-    

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

@@ -52,26 +52,33 @@ Null_Allowed:       yes
 
 PARAMETER_TABLE:
 
-Parameter_Name:     input_load
-Description:        "input load value (F)" 
-Data_Type:          real                          
-Default_Value:      1.0e-12                    
-Limits:             -                                 
-Vector:              no                         
-Vector_Bounds:       -                         
-Null_Allowed:       yes                            
+Parameter_Name:     input_load			enable_load
+Description:        "input load value (F)"	"enable load value (F)" 
+Data_Type:          real                        real
+Default_Value:      1.0e-12                     1.0e-12
+Limits:             -                           -
+Vector:             no                          no
+Vector_Bounds:      -				-
+Null_Allowed:       yes				yes
 
 
 PARAMETER_TABLE:
 
-Parameter_Name:     enable_load
-Description:        "enable load value (F)" 
-Data_Type:          real                          
-Default_Value:      1.0e-12                    
-Limits:             -                                 
-Vector:              no                         
-Vector_Bounds:       -                         
-Null_Allowed:       yes                            
+
+Parameter_Name:     inertial_delay		family
+Description:        "swallow short pulses"	"Logic family for bridging"
+Data_Type:          boolean  	   		string
+Default_Value:      false			-
+Limits:             -				-
+Vector:             no				no
+Vector_Bounds:      -				-
+Null_Allowed:       yes				yes
+
+STATIC_VAR_TABLE:
+
+Static_Var_Name:    is_inertial
+Data_Type:	    boolean
+Description:        "using inertial delay"