// license:BSD-3-Clause // copyright-holders:Mike Balfour /************************************************************************* audio\canyon.c *************************************************************************/ #include "emu.h" #include "includes/canyon.h" #include "sound/discrete.h" /************************************* * * Write handlers * *************************************/ WRITE8_MEMBER(canyon_state::canyon_motor_w) { m_discrete->write(NODE_RELATIVE(CANYON_MOTOR1_DATA, (offset & 0x01)), data & 0x0f); } WRITE8_MEMBER(canyon_state::canyon_explode_w) { m_discrete->write(CANYON_EXPLODE_DATA, data >> 4); } /************************************************************************/ /* canyon Sound System Analog emulation */ /************************************************************************/ static const discrete_555_desc canyonWhistl555 = { DISC_555_OUT_CAP | DISC_555_OUT_AC, 5, // B+ voltage of 555 DEFAULT_555_VALUES }; static const discrete_lfsr_desc canyon_lfsr = { DISC_CLK_IS_FREQ, 16, /* Bit Length */ 0, /* Reset Value */ 6, /* Use Bit 6 as XOR input 0 */ 8, /* Use Bit 8 as XOR input 1 */ DISC_LFSR_XNOR, /* Feedback stage1 is XNOR */ DISC_LFSR_OR, /* Feedback stage2 is just stage 1 output OR with external feed */ DISC_LFSR_REPLACE, /* Feedback stage3 replaces the shifted register contents */ 0x000001, /* Everything is shifted into the first bit only */ 0, /* Output is not inverted, Active Low Reset */ 15 /* Output bit */ }; /* Nodes - Sounds */ #define CANYON_MOTORSND1 NODE_10 #define CANYON_MOTORSND2 NODE_11 #define CANYON_EXPLODESND NODE_12 #define CANYON_WHISTLESND1 NODE_13 #define CANYON_WHISTLESND2 NODE_14 #define CANYON_NOISE NODE_15 DISCRETE_SOUND_START(canyon_discrete) /************************************************/ /* Canyon sound system: 5 Sound Sources */ /* Relative Volume */ /* 1/2) Motor 14.29% */ /* 3) Explode 100.00% */ /* 4/5) Whistle 51.94% */ /* Relative volumes calculated from resitor */ /* network in combiner circuit taking voltages */ /* into account */ /* */ /* Motor 3.8V * 5/(5+100) = 0.1810 */ /* Explode 3.8V * 5/(5+10) = 1.2667 */ /* Whistle 5.0V * 5/(5+33) = 0.6579 */ /* */ /************************************************/ /************************************************/ /* Input register mapping for canyon */ /************************************************/ DISCRETE_INPUTX_DATA (CANYON_MOTOR1_DATA , -1, 0x0f, 0) DISCRETE_INPUTX_DATA (CANYON_MOTOR2_DATA , -1, 0x0f, 0) DISCRETE_INPUT_LOGIC (CANYON_WHISTLE1_EN) DISCRETE_INPUT_LOGIC (CANYON_WHISTLE2_EN) DISCRETE_INPUT_NOT (CANYON_ATTRACT1_EN) DISCRETE_INPUT_NOT (CANYON_ATTRACT2_EN) DISCRETE_INPUTX_DATA (CANYON_EXPLODE_DATA, 1000.0/15.0, 0, 0.0) /************************************************/ /* Motor sound circuit is based on a 556 VCO */ /* with the input frequency set by the MotorSND */ /* latch (4 bit). This freqency is then used to */ /* driver a modulo 12 counter, with div6, 4 & 3 */ /* summed as the output of the circuit. */ /* VCO Output is Sq wave = 27-382Hz */ /* F1 freq - (Div6) */ /* F2 freq = (Div4) */ /* F3 freq = (Div3) 33.3% duty, 33.3 deg phase */ /* To generate the frequency we take the freq. */ /* diff. and /15 to get all the steps between */ /* 0 - 15. Then add the low frequency and send */ /* that value to a squarewave generator. */ /* Also as the frequency changes, it ramps due */ /* to a 1uf capacitor on the R-ladder. */ /* Note the VCO freq. is controlled by a 250k */ /* pot. The freq. used here is for the pot set */ /* to 125k. The low freq is allways the same. */ /* This adjusts the high end. */ /* 0k = 214Hz. 250k = 4416Hz */ /************************************************/ DISCRETE_RCFILTER(NODE_20, CANYON_MOTOR1_DATA, 123000, 1e-6) DISCRETE_ADJUSTMENT(NODE_21, (214.0-27.0)/12/15, (4416.0-27.0)/12/15, DISC_LOGADJ, "MOTOR1") DISCRETE_MULTIPLY(NODE_22, NODE_20, NODE_21) DISCRETE_MULTADD(NODE_23, NODE_22, 2, 27.0/6) /* F1 = /12*2 = /6 */ DISCRETE_SQUAREWAVE(NODE_24, 1, NODE_23, (142.9/3), 50.0, 0, 0) DISCRETE_RCFILTER(NODE_25, NODE_24, 10000, 1e-7) DISCRETE_MULTADD(NODE_26, NODE_22, 3, 27.0/4) /* F2 = /12*3 = /4 */ DISCRETE_SQUAREWAVE(NODE_27, 1, NODE_26, (142.9/3), 50.0, 0, 0) DISCRETE_RCFILTER(NODE_28, NODE_27, 10000, 1e-7) DISCRETE_MULTADD(NODE_29, NODE_22, 4, 27.0/3) /* F3 = /12*4 = /3 */ DISCRETE_SQUAREWAVE(NODE_30, 1, NODE_29, (142.9/3), 100.0/3, 0, 360.0/3) DISCRETE_RCFILTER(NODE_31, NODE_30, 10000, 1e-7) DISCRETE_ADDER3(CANYON_MOTORSND1, CANYON_ATTRACT1_EN, NODE_25, NODE_28, NODE_31) /************************************************/ /* The motor2 sound is basically the same as */ /* for 1. But I shifted the frequencies up for */ /* it to sound different from motor 1. */ /************************************************/ DISCRETE_RCFILTER(NODE_40, CANYON_MOTOR2_DATA, 123000, 1e-6) DISCRETE_ADJUSTMENT(NODE_41, (214.0-27.0)/12/15, (4416.0-27.0)/12/15, DISC_LOGADJ, "MOTOR2") DISCRETE_MULTIPLY(NODE_42, NODE_40, NODE_41) DISCRETE_MULTADD(NODE_43, NODE_42, 2, 27.0/6) /* F1 = /12*2 = /6 */ DISCRETE_SQUAREWAVE(NODE_44, 1, NODE_43, (142.9/3), 50.0, 0, 0) DISCRETE_RCFILTER(NODE_45, NODE_44, 10000, 1e-7) DISCRETE_MULTADD(NODE_46, NODE_42, 3, 27.0/4) /* F2 = /12*3 = /4 */ DISCRETE_SQUAREWAVE(NODE_47, 1, NODE_46, (142.9/3), 50.0, 0, 0) DISCRETE_RCFILTER(NODE_48, NODE_47, 10000, 1e-7) DISCRETE_MULTADD(NODE_49, NODE_42, 4, 27.0/3) /* F3 = /12*4 = /3 */ DISCRETE_SQUAREWAVE(NODE_50, 1, NODE_49, (142.9/3), 100.0/3, 0, 360.0/3) DISCRETE_RCFILTER(NODE_51, NODE_50, 10000, 1e-7) DISCRETE_ADDER3(CANYON_MOTORSND2, CANYON_ATTRACT2_EN, NODE_45, NODE_48, NODE_51) /************************************************/ /* Explode circuit is built around a noise */ /* generator built from 2 shift registers that */ /* are clocked by the 2V signal. */ /* 2V = HSYNC/4 */ /* = 15750/4 */ /* Output is binary weighted with 4 bits of */ /* crash volume. */ /************************************************/ DISCRETE_LOGIC_OR(NODE_60, CANYON_ATTRACT1_EN, CANYON_ATTRACT2_EN) DISCRETE_LFSR_NOISE(CANYON_NOISE, NODE_60, NODE_60, 15750.0/4, 1.0, 0, 0, &canyon_lfsr) DISCRETE_MULTIPLY(NODE_61, CANYON_NOISE, CANYON_EXPLODE_DATA) DISCRETE_RCFILTER(CANYON_EXPLODESND, NODE_61, 545, 5e-6) /************************************************/ /* Whistle circuit is a 555 capacitor charge */ /* waveform. The original game pot varies from */ /* 0-100k, but we are going to limit it because */ /* below 50k the frequency is too high. */ /* When triggered it starts at it's highest */ /* frequency, then decays at the rate set by */ /* a 68k resistor and 22uf capacitor. */ /************************************************/ DISCRETE_ADJUSTMENT(NODE_70, 50000, 100000, DISC_LINADJ, "WHISTLE1") /* R59 */ DISCRETE_MULTADD(NODE_71, CANYON_WHISTLE1_EN, 3.05-0.33, 0.33) DISCRETE_RCDISC2(NODE_72, CANYON_WHISTLE1_EN, NODE_71, 1.0, NODE_71, 68000.0, 2.2e-5) /* CV */ DISCRETE_555_ASTABLE_CV(NODE_73, CANYON_WHISTLE1_EN, 33000, NODE_70, 1e-8, NODE_72, &canyonWhistl555) DISCRETE_MULTIPLY(CANYON_WHISTLESND1, NODE_73, 519.4/3.3) DISCRETE_ADJUSTMENT(NODE_75, 50000, 100000, DISC_LINADJ, "WHISTLE2") /* R69 */ DISCRETE_MULTADD(NODE_76, CANYON_WHISTLE2_EN, 3.05-0.33, 0.33) DISCRETE_RCDISC2(NODE_77, CANYON_WHISTLE2_EN, NODE_76, 1.0, NODE_76, 68000.0, 2.2e-5) /* CV */ DISCRETE_555_ASTABLE_CV(NODE_78, CANYON_WHISTLE2_EN, 33000, NODE_75, 1e-8, NODE_77, &canyonWhistl555) DISCRETE_MULTIPLY(CANYON_WHISTLESND2, NODE_78, 519.4/3.3) /************************************************/ /* Combine all 5 sound sources. */ /* Add some final gain to get to a good sound */ /* level. */ /************************************************/ DISCRETE_ADDER3(NODE_90, 1, CANYON_MOTORSND1, CANYON_EXPLODESND, CANYON_WHISTLESND1) DISCRETE_ADDER3(NODE_91, 1, CANYON_MOTORSND2, CANYON_EXPLODESND, CANYON_WHISTLESND2) DISCRETE_OUTPUT(NODE_90, 77) DISCRETE_OUTPUT(NODE_91, 77) DISCRETE_SOUND_END