1 // license:BSD-3-Clause
2 // copyright-holders:Mike Balfour
3 /*************************************************************************
4
5 audio\canyon.cpp
6
7 *************************************************************************/
8 #include "emu.h"
9 #include "includes/canyon.h"
10 #include "sound/discrete.h"
11
12
13 /*************************************
14 *
15 * Write handlers
16 *
17 *************************************/
18
canyon_motor_w(offs_t offset,uint8_t data)19 void canyon_state::canyon_motor_w(offs_t offset, uint8_t data)
20 {
21 m_discrete->write(NODE_RELATIVE(CANYON_MOTOR1_DATA, (offset & 0x01)), data & 0x0f);
22 }
23
24
canyon_explode_w(uint8_t data)25 void canyon_state::canyon_explode_w(uint8_t data)
26 {
27 m_discrete->write(CANYON_EXPLODE_DATA, data >> 4);
28 }
29
30
31 /************************************************************************/
32 /* canyon Sound System Analog emulation */
33 /************************************************************************/
34
35 static const discrete_555_desc canyonWhistl555 =
36 {
37 DISC_555_OUT_CAP | DISC_555_OUT_AC,
38 5, // B+ voltage of 555
39 DEFAULT_555_VALUES
40 };
41
42 static const discrete_lfsr_desc canyon_lfsr =
43 {
44 DISC_CLK_IS_FREQ,
45 16, /* Bit Length */
46 0, /* Reset Value */
47 6, /* Use Bit 6 as XOR input 0 */
48 8, /* Use Bit 8 as XOR input 1 */
49 DISC_LFSR_XNOR, /* Feedback stage1 is XNOR */
50 DISC_LFSR_OR, /* Feedback stage2 is just stage 1 output OR with external feed */
51 DISC_LFSR_REPLACE, /* Feedback stage3 replaces the shifted register contents */
52 0x000001, /* Everything is shifted into the first bit only */
53 0, /* Output is not inverted, Active Low Reset */
54 15 /* Output bit */
55 };
56
57 /* Nodes - Sounds */
58 #define CANYON_MOTORSND1 NODE_10
59 #define CANYON_MOTORSND2 NODE_11
60 #define CANYON_EXPLODESND NODE_12
61 #define CANYON_WHISTLESND1 NODE_13
62 #define CANYON_WHISTLESND2 NODE_14
63 #define CANYON_NOISE NODE_15
64
65 DISCRETE_SOUND_START(canyon_discrete)
66 /************************************************/
67 /* Canyon sound system: 5 Sound Sources */
68 /* Relative Volume */
69 /* 1/2) Motor 14.29% */
70 /* 3) Explode 100.00% */
71 /* 4/5) Whistle 51.94% */
72 /* Relative volumes calculated from resitor */
73 /* network in combiner circuit taking voltages */
74 /* into account */
75 /* */
76 /* Motor 3.8V * 5/(5+100) = 0.1810 */
77 /* Explode 3.8V * 5/(5+10) = 1.2667 */
78 /* Whistle 5.0V * 5/(5+33) = 0.6579 */
79 /* */
80 /************************************************/
81
82 /************************************************/
83 /* Input register mapping for canyon */
84 /************************************************/
85 DISCRETE_INPUTX_DATA (CANYON_MOTOR1_DATA , -1, 0x0f, 0)
86 DISCRETE_INPUTX_DATA (CANYON_MOTOR2_DATA , -1, 0x0f, 0)
87 DISCRETE_INPUT_LOGIC (CANYON_WHISTLE1_EN)
88 DISCRETE_INPUT_LOGIC (CANYON_WHISTLE2_EN)
89 DISCRETE_INPUT_NOT (CANYON_ATTRACT1_EN)
90 DISCRETE_INPUT_NOT (CANYON_ATTRACT2_EN)
91 DISCRETE_INPUTX_DATA (CANYON_EXPLODE_DATA, 1000.0/15.0, 0, 0.0)
92
93 /************************************************/
94 /* Motor sound circuit is based on a 556 VCO */
95 /* with the input frequency set by the MotorSND */
96 /* latch (4 bit). This freqency is then used to */
97 /* driver a modulo 12 counter, with div6, 4 & 3 */
98 /* summed as the output of the circuit. */
99 /* VCO Output is Sq wave = 27-382Hz */
100 /* F1 freq - (Div6) */
101 /* F2 freq = (Div4) */
102 /* F3 freq = (Div3) 33.3% duty, 33.3 deg phase */
103 /* To generate the frequency we take the freq. */
104 /* diff. and /15 to get all the steps between */
105 /* 0 - 15. Then add the low frequency and send */
106 /* that value to a squarewave generator. */
107 /* Also as the frequency changes, it ramps due */
108 /* to a 1uf capacitor on the R-ladder. */
109 /* Note the VCO freq. is controlled by a 250k */
110 /* pot. The freq. used here is for the pot set */
111 /* to 125k. The low freq is allways the same. */
112 /* This adjusts the high end. */
113 /* 0k = 214Hz. 250k = 4416Hz */
114 /************************************************/
115 DISCRETE_RCFILTER(NODE_20, CANYON_MOTOR1_DATA, 123000, 1e-6)
116 DISCRETE_ADJUSTMENT(NODE_21, (214.0-27.0)/12/15, (4416.0-27.0)/12/15, DISC_LOGADJ, "MOTOR1")
117 DISCRETE_MULTIPLY(NODE_22, NODE_20, NODE_21)
118
119 DISCRETE_MULTADD(NODE_23, NODE_22, 2, 27.0/6) /* F1 = /12*2 = /6 */
120 DISCRETE_SQUAREWAVE(NODE_24, 1, NODE_23, (142.9/3), 50.0, 0, 0)
121 DISCRETE_RCFILTER(NODE_25, NODE_24, 10000, 1e-7)
122
123 DISCRETE_MULTADD(NODE_26, NODE_22, 3, 27.0/4) /* F2 = /12*3 = /4 */
124 DISCRETE_SQUAREWAVE(NODE_27, 1, NODE_26, (142.9/3), 50.0, 0, 0)
125 DISCRETE_RCFILTER(NODE_28, NODE_27, 10000, 1e-7)
126
127 DISCRETE_MULTADD(NODE_29, NODE_22, 4, 27.0/3) /* F3 = /12*4 = /3 */
128 DISCRETE_SQUAREWAVE(NODE_30, 1, NODE_29, (142.9/3), 100.0/3, 0, 360.0/3)
129 DISCRETE_RCFILTER(NODE_31, NODE_30, 10000, 1e-7)
130
131 DISCRETE_ADDER3(CANYON_MOTORSND1, CANYON_ATTRACT1_EN, NODE_25, NODE_28, NODE_31)
132
133 /************************************************/
134 /* The motor2 sound is basically the same as */
135 /* for 1. But I shifted the frequencies up for */
136 /* it to sound different from motor 1. */
137 /************************************************/
138 DISCRETE_RCFILTER(NODE_40, CANYON_MOTOR2_DATA, 123000, 1e-6)
139 DISCRETE_ADJUSTMENT(NODE_41, (214.0-27.0)/12/15, (4416.0-27.0)/12/15, DISC_LOGADJ, "MOTOR2")
140 DISCRETE_MULTIPLY(NODE_42, NODE_40, NODE_41)
141
142 DISCRETE_MULTADD(NODE_43, NODE_42, 2, 27.0/6) /* F1 = /12*2 = /6 */
143 DISCRETE_SQUAREWAVE(NODE_44, 1, NODE_43, (142.9/3), 50.0, 0, 0)
144 DISCRETE_RCFILTER(NODE_45, NODE_44, 10000, 1e-7)
145
146 DISCRETE_MULTADD(NODE_46, NODE_42, 3, 27.0/4) /* F2 = /12*3 = /4 */
147 DISCRETE_SQUAREWAVE(NODE_47, 1, NODE_46, (142.9/3), 50.0, 0, 0)
148 DISCRETE_RCFILTER(NODE_48, NODE_47, 10000, 1e-7)
149
150 DISCRETE_MULTADD(NODE_49, NODE_42, 4, 27.0/3) /* F3 = /12*4 = /3 */
151 DISCRETE_SQUAREWAVE(NODE_50, 1, NODE_49, (142.9/3), 100.0/3, 0, 360.0/3)
152 DISCRETE_RCFILTER(NODE_51, NODE_50, 10000, 1e-7)
153
154 DISCRETE_ADDER3(CANYON_MOTORSND2, CANYON_ATTRACT2_EN, NODE_45, NODE_48, NODE_51)
155
156 /************************************************/
157 /* Explode circuit is built around a noise */
158 /* generator built from 2 shift registers that */
159 /* are clocked by the 2V signal. */
160 /* 2V = HSYNC/4 */
161 /* = 15750/4 */
162 /* Output is binary weighted with 4 bits of */
163 /* crash volume. */
164 /************************************************/
165 DISCRETE_LOGIC_OR(NODE_60, CANYON_ATTRACT1_EN, CANYON_ATTRACT2_EN)
166 DISCRETE_LFSR_NOISE(CANYON_NOISE, NODE_60, NODE_60, 15750.0/4, 1.0, 0, 0, &canyon_lfsr)
167
168 DISCRETE_MULTIPLY(NODE_61, CANYON_NOISE, CANYON_EXPLODE_DATA)
169 DISCRETE_RCFILTER(CANYON_EXPLODESND, NODE_61, 545, 5e-6)
170
171 /************************************************/
172 /* Whistle circuit is a 555 capacitor charge */
173 /* waveform. The original game pot varies from */
174 /* 0-100k, but we are going to limit it because */
175 /* below 50k the frequency is too high. */
176 /* When triggered it starts at it's highest */
177 /* frequency, then decays at the rate set by */
178 /* a 68k resistor and 22uf capacitor. */
179 /************************************************/
180 DISCRETE_ADJUSTMENT(NODE_70, 50000, 100000, DISC_LINADJ, "WHISTLE1") /* R59 */
181 DISCRETE_MULTADD(NODE_71, CANYON_WHISTLE1_EN, 3.05-0.33, 0.33)
182 DISCRETE_RCDISC2(NODE_72, CANYON_WHISTLE1_EN, NODE_71, 1.0, NODE_71, 68000.0, 2.2e-5) /* CV */
183 DISCRETE_555_ASTABLE_CV(NODE_73, CANYON_WHISTLE1_EN, 33000, NODE_70, 1e-8, NODE_72, &canyonWhistl555)
184 DISCRETE_MULTIPLY(CANYON_WHISTLESND1, NODE_73, 519.4/3.3)
185
186 DISCRETE_ADJUSTMENT(NODE_75, 50000, 100000, DISC_LINADJ, "WHISTLE2") /* R69 */
187 DISCRETE_MULTADD(NODE_76, CANYON_WHISTLE2_EN, 3.05-0.33, 0.33)
188 DISCRETE_RCDISC2(NODE_77, CANYON_WHISTLE2_EN, NODE_76, 1.0, NODE_76, 68000.0, 2.2e-5) /* CV */
189 DISCRETE_555_ASTABLE_CV(NODE_78, CANYON_WHISTLE2_EN, 33000, NODE_75, 1e-8, NODE_77, &canyonWhistl555)
190 DISCRETE_MULTIPLY(CANYON_WHISTLESND2, NODE_78, 519.4/3.3)
191
192 /************************************************/
193 /* Combine all 5 sound sources. */
194 /* Add some final gain to get to a good sound */
195 /* level. */
196 /************************************************/
197 DISCRETE_ADDER3(NODE_90, 1, CANYON_MOTORSND1, CANYON_EXPLODESND, CANYON_WHISTLESND1)
198 DISCRETE_ADDER3(NODE_91, 1, CANYON_MOTORSND2, CANYON_EXPLODESND, CANYON_WHISTLESND2)
199
200 DISCRETE_OUTPUT(NODE_90, 77)
201 DISCRETE_OUTPUT(NODE_91, 77)
202 DISCRETE_SOUND_END
203