Added discrete 74LS624(56789) implementation

- DISCRETE_74LS624 is a VCO needed for dkongjr
- Supports Logic, Energy and Count outputs

src/emu/sound/disc_dev.c

@@ -100,6 +100,12 @@ struct dsd_566_context
 	double		triOffset;		// used to shift a triangle to AC
 };
 
+struct dsd_ls624_context
+{
+	int			state;
+	double		remain;			// remaining time from last step
+	int			outtype;
+};
 
 
 /* Test to see if basic 555 options are valid. */
@@ -1370,3 +1376,90 @@ void dsd_566_reset(node_description *node)
 	/* Step the output */
 	dsd_566_step(node);
 }
+
+/************************************************************************
+ *
+ * DSD_LS624 - Usage of node_description values
+ *
+ * input[0]    - Enable input value
+ * input[1]    - Modulation Voltage
+ * input[2]    - Range Voltage
+ * input[3]    - C value
+ * input[4]    - Output type
+ *
+ * Dec 2007, Couriersud
+ ************************************************************************/
+#define DSD_LS624__ENABLE	(*(node->input[0]))
+#define DSD_LS624__VMOD		(*(node->input[1]))
+#define DSD_LS624__VRNG		(*(node->input[2]))
+#define DSD_LS624__C		(*(node->input[3]))
+#define DSD_LS624__OUTTYPE	(*(node->input[4]))
+
+/* 
+ * These formulas are derived from diagrams in the datasheet!
+ * They are not based on any law. The function is not
+ * described anywhere.
+ */
+
+#define LS624_F1(x)			(0.19 + 20.0/90.0*(x))
+#define LS624_T(_C, _R, _F)		(-600.0 * (_C) * log(1.0-LS624_F1(_R)*0.12/LS624_F1(_F)))
+
+void dsd_ls624_step(node_description *node)
+{
+	struct dsd_ls624_context *context = node->context;
+
+	if (DSD_LS624__ENABLE)
+	{
+		double dt;	// change in time
+		double sample_t;
+		double t;
+		int lst, cntf=0, cntr=0;
+
+		sample_t = discrete_current_context->sample_time;	// Change in time
+		dt = LS624_T(DSD_LS624__C, DSD_LS624__VRNG, DSD_LS624__VMOD);
+		dt = 16 * dt;
+		t = context->remain;
+		lst = context->state;
+		while (t + dt < sample_t)
+		{
+			context->state = (1-context->state);
+			if (context->state)
+				cntr++;
+			else
+				cntf++;
+			t += dt;
+		}
+		context->remain = t - sample_t;
+
+		switch (context->outtype)
+		{
+			case DISC_LS624_OUT_ENERGY:
+				node->output = ((double) lst) * (1.0+context->remain/sample_t) - ((double) context->state) * context->remain/sample_t;
+				break;
+			case DISC_LS624_OUT_LOGIC:
+				node->output = context->state;
+				break;
+			case DISC_LS624_OUT_COUNT_F:
+				node->output = cntf;
+				break;
+			case DISC_LS624_OUT_COUNT_R:
+				node->output = cntr;
+				break;
+		}
+
+	}
+	else
+		node->output = 0;
+}
+
+void dsd_ls624_reset(node_description *node)
+{
+	struct dsd_ls624_context *context = node->context;
+
+	context->remain = 0;
+	context->state = 0;
+	context->outtype = DSD_LS624__OUTTYPE;
+	
+	/* Step the output */
+	dsd_ls624_step(node);
+}

src/emu/sound/discrete.c

@@ -259,7 +259,7 @@ static const discrete_module module_list[] =
 	{ DSD_555_CC      ,"DSD_555_CC"      ,sizeof(struct dsd_555_cc_context)      ,dsd_555_cc_reset      ,dsd_555_cc_step      },
 	{ DSD_555_VCO1    ,"DSD_555_VCO1"    ,sizeof(struct dsd_555_vco1_context)    ,dsd_555_vco1_reset    ,dsd_555_vco1_step    },
 	{ DSD_566         ,"DSD_566"         ,sizeof(struct dsd_566_context)         ,dsd_566_reset         ,dsd_566_step         },
-
+	{ DSD_LS624       ,"DSD_LS624"       ,sizeof(struct dsd_ls624_context)       ,dsd_ls624_reset       ,dsd_ls624_step       },
 	/* must be the last one */
 	{ DSS_NULL        ,"DSS_NULL"        ,0                                      ,NULL                  ,NULL                 }
 };

src/emu/sound/discrete.h

@@ -2911,9 +2911,9 @@
  *
  *     DISCRETE_566(name of node,
  *                  enable node or static value,
+ *                  vMod node or static value,
  *                  R node or static value in ohms,
  *                  C node or static value in Farads,
- *                  vMod node or static value,
  *                  address of discrete_566_desc structure)
  *
  *     discrete_566_desc = {options, vPlus, vNeg}
@@ -2929,6 +2929,50 @@
  *
  ***********************************************************************
  *
+ * DISCRETE_74LS624 - VCO.
+ *
+ * Simplified 74LS624 - calculated frequencies should match datasheet
+ * for C > 1nF. Output is Logic (1/0)                      
+ * 
+ * The datasheet gives no formulae. The implementation therefore is
+ * a rough model of the diagrams given. 
+ * 
+ * For a LS628, use VRng = 3.2
+ * 
+ *                          V+
+ *                           |
+ *                     .---------.
+ *   vRng >------------|Rng  V+  |
+ *                     |         |
+ *   vMod >------------|Freq   Z |---------> Netlist Node
+ *                     |         |
+ *                 .---|CX1      |
+ *                 |   |         |
+ *                ---  |         |
+ *              C ---  |         |
+ *                 |   |         |
+ *                 '---|CX2      |
+ *                     '---------'
+ *                         | 
+ *                        GND
+ *
+ *  Declaration syntax
+ *
+ *     DISCRETE_74LS624(name of node,
+ *                      enable node or static value,
+ *                      vMod node or static value,
+ *                      vRng node or static value,
+ *                      C node or static value in Farads,
+ * 						Type of output static value)
+ * 
+ * Type of Output
+ *      DISC_LS624_OUT_ENERGY	Energy - use for audio output
+ *      DISC_LS624_OUT_LOGIC    Logic ( 0 or 1)
+ *      DISC_LS624_OUT_COUNT_F	Number of Falling edges
+ *      DISC_LS624_OUT_COUNT_R	Number of Rising  edges
+ * 
+ ***********************************************************************
+ *
  * DISCRETE_CUSTOMx - Link to custom code
  *     where x = 1 to 5
  *
@@ -3208,6 +3252,11 @@ enum
 
 #define DISC_566_OUT_MASK				0x30	/* Bits that define output type.
                                                  * Used only internally in module. */
+/* LS624 output flags */
+#define DISC_LS624_OUT_ENERGY			0x01
+#define DISC_LS624_OUT_LOGIC			0x02
+#define DISC_LS624_OUT_COUNT_F			0x03
+#define DISC_LS624_OUT_COUNT_R			0x04
 
 /* Oneshot types */
 #define DISC_ONESHOT_FEDGE				0x00
@@ -3739,6 +3788,7 @@ enum
 	DSD_555_CC,			/* Constant Current 555 circuit (VCO)*/
 	DSD_555_VCO1,		/* Op-Amp linear ramp based 555 VCO */
 	DSD_566,			/* NE566 Emulation */
+	DSD_LS624,			/* 74LS624 Emulation */
 
 	/* Custom */
 	DST_CUSTOM,			/* whatever you want */
@@ -3902,7 +3952,7 @@ enum
 #define DISCRETE_555_VCO1(NODE,RESET,VIN,OPTIONS)                       { NODE, DSD_555_VCO1    , 3, { RESET,VIN,NODE_NC }, { RESET,VIN,-1 }, OPTIONS, "555 VCO1 - Op-Amp type" },
 #define DISCRETE_555_VCO1_CV(NODE,RESET,VIN,CTRLV,OPTIONS)              { NODE, DSD_555_VCO1    , 3, { RESET,VIN,CTRLV }, { RESET,VIN,CTRLV }, OPTIONS, "555 VCO1 with CV - Op-Amp type" },
 #define DISCRETE_566(NODE,ENAB,VMOD,R,C,OPTIONS)                        { NODE, DSD_566         , 4, { ENAB,VMOD,R,C }, { ENAB,VMOD,R,C }, OPTIONS, "566" },
-
+#define DISCRETE_74LS624(NODE,ENAB,VMOD,VRNG,C,OUTTYPE)                 { NODE, DSD_LS624       , 5, { ENAB,VMOD,VRNG,C,NODE_NC }, { ENAB,VMOD,VRNG,C, OUTTYPE }, NULL, "74LS624" },
 #define DISCRETE_CSVLOG1(NODE1)                                    { NODE_SPECIAL, DSO_CSVLOG   , 1, { NODE1 }, { NODE1 }, NULL, "CSV Log 1 Node" },
 #define DISCRETE_CSVLOG2(NODE1,NODE2)                              { NODE_SPECIAL, DSO_CSVLOG   , 2, { NODE1,NODE2 }, { NODE1,NODE2 }, NULL, "CSV Log 2 Nodes" },
 #define DISCRETE_CSVLOG3(NODE1,NODE2,NODE3)                        { NODE_SPECIAL, DSO_CSVLOG   , 3, { NODE1,NODE2,NODE3 }, { NODE1,NODE2,NODE3 }, NULL, "CSV Log 3 Nodes" },