// license:BSD-3-Clause // copyright-holders:Derrick Renaud /************************************************************************* audio\dragrace.c *************************************************************************/ #include "emu.h" #include "includes/dragrace.h" #include "sound/discrete.h" /************************************************************************/ /* dragrace Sound System Analog emulation */ /************************************************************************/ static const discrete_lfsr_desc dragrace_lfsr = { DISC_CLK_IS_FREQ, 16, /* Bit Length */ 0, /* Reset Value */ 0, /* Use Bit 0 as XOR input 0 */ 14, /* Use Bit 14 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 already inverted by XNOR */ 15 /* Output bit */ }; /* Nodes - Sounds */ #define DRAGRACE_NOISE NODE_10 #define DRAGRACE_SCREECH1_SND NODE_11 #define DRAGRACE_SCREECH2_SND NODE_12 #define DRAGRACE_LOTONE_SND NODE_13 #define DRAGRACE_HITONE_SND NODE_14 #define DRAGRACE_TONE_SND NODE_15 #define DRAGRACE_EXPLODE1_SND NODE_16 #define DRAGRACE_EXPLODE2_SND NODE_17 #define DRAGRACE_MOTOR1_SND NODE_18 #define DRAGRACE_MOTOR2_SND NODE_19 DISCRETE_SOUND_START(dragrace_discrete) /************************************************/ /* dragrace Effects Relataive Gain Table */ /* */ /* Effect V-ampIn Gain ratio Relative */ /* LoTone 3.8 10/32 593.8 */ /* HiTone 3.8 10/32 593.8 */ /* Screech 3.8 10/330 57.6 */ /* Motor 3.8 10/32.67 581.6 */ /* Explode 5.0 10/25 1000.0 */ /************************************************/ /************************************************/ /* Input register mapping for dragrace */ /************************************************/ DISCRETE_INPUT_LOGIC(DRAGRACE_SCREECH1_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_SCREECH2_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_LOTONE_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_HITONE_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_EXPLODE1_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_EXPLODE2_EN) DISCRETE_INPUT_DATA (DRAGRACE_MOTOR1_DATA) DISCRETE_INPUT_DATA (DRAGRACE_MOTOR2_DATA) DISCRETE_INPUT_LOGIC(DRAGRACE_MOTOR1_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_MOTOR2_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_KLEXPL1_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_KLEXPL2_EN) DISCRETE_INPUT_LOGIC(DRAGRACE_ATTRACT_EN) /************************************************/ /* 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 2.2uf 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 */ /* NOTE: freqs are ripped from Sprint for now. */ /************************************************/ DISCRETE_RCFILTER(NODE_20, DRAGRACE_MOTOR1_DATA, 119898, 2.2e-6) DISCRETE_ADJUSTMENT(NODE_21, (214.0-27.0)/12/31, (4416.0-27.0)/12/31, 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, (581.6/3), 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, (581.6/3), 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, (581.6/3), 100.0/3, 0, 360.0/3) DISCRETE_RCFILTER(NODE_31, NODE_30, 10000, 1e-7) DISCRETE_ADDER3(DRAGRACE_MOTOR1_SND, DRAGRACE_MOTOR1_EN, NODE_25, NODE_28, NODE_31) /************************************************/ /* Car2 motor sound is basically the same as */ /* Car1. But I shifted the frequencies up for */ /* it to sound different from car1. */ /************************************************/ DISCRETE_RCFILTER(NODE_40, DRAGRACE_MOTOR2_DATA, 119898, 2.2e-6) DISCRETE_ADJUSTMENT(NODE_41, (214.0-27.0)/12/31, (4416.0-27.0)/12/31, 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, (581.6/3), 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, (581.6/3), 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, (581.6/3), 100.0/3, 0, 360.0/3) DISCRETE_RCFILTER(NODE_51, NODE_50, 10000, 1e-7) DISCRETE_ADDER3(DRAGRACE_MOTOR2_SND, DRAGRACE_MOTOR2_EN, NODE_45, NODE_48, NODE_51) /************************************************/ /* Explosion circuit is built around a noise */ /* generator built from 2 shift registers that */ /* are clocked by the 1V signal. */ /* 1V = HSYNC/2 */ /* = 15750/2 */ /* Output is integrated to apply decay. */ /************************************************/ DISCRETE_LFSR_NOISE(DRAGRACE_NOISE, 1, DRAGRACE_ATTRACT_EN, 15750.0/2, 1.0, 0, 0, &dragrace_lfsr) DISCRETE_RAMP(NODE_61, DRAGRACE_EXPLODE1_EN, DRAGRACE_EXPLODE1_EN, (1000.0-0.0)/1, 1000.0, 0.0, 1000.0) DISCRETE_MULTIPLY(NODE_62, DRAGRACE_NOISE, NODE_61) DISCRETE_RCFILTER(NODE_63, NODE_62, 1500, 2.2e-7) DISCRETE_MULTIPLY(DRAGRACE_EXPLODE1_SND, NODE_63, DRAGRACE_KLEXPL1_EN) DISCRETE_RAMP(NODE_66, DRAGRACE_EXPLODE2_EN, DRAGRACE_EXPLODE2_EN, (1000.0-0.0)/1, 1000.0, 0.0, 1000.0) DISCRETE_MULTIPLY(NODE_67, DRAGRACE_NOISE, NODE_66) DISCRETE_RCFILTER(NODE_68, NODE_67, 1500, 2.2e-7) DISCRETE_MULTIPLY(DRAGRACE_EXPLODE2_SND, NODE_68, DRAGRACE_KLEXPL2_EN) /************************************************/ /* Skid circuits takes the noise output from */ /* the crash circuit and applies +ve feedback */ /* to cause oscillation. There is also an RC */ /* filter on the input to the feedback cct. */ /* RC is 1K & 10uF */ /* Feedback cct is modelled by using the RC out */ /* as the frequency input on a VCO, */ /* breadboarded freq range as: */ /* 0 = 940Hz, 34% duty */ /* 1 = 630Hz, 29% duty */ /* the duty variance is so small we ignore it */ /************************************************/ DISCRETE_INVERT(NODE_70, DRAGRACE_NOISE) DISCRETE_MULTADD(NODE_71, NODE_70, 940.0-630.0, ((940.0-630.0)/2)+630.0) DISCRETE_RCFILTER(NODE_72, NODE_71, 1000, 1e-5) DISCRETE_SQUAREWAVE(NODE_73, 1, NODE_72, 407.8, 31.5, 0, 0.0) DISCRETE_ONOFF(DRAGRACE_SCREECH1_SND, DRAGRACE_SCREECH1_EN, NODE_73) DISCRETE_ONOFF(DRAGRACE_SCREECH2_SND, DRAGRACE_SCREECH2_EN, NODE_73) /************************************************/ /* LoTone = 32V = 15750Hz/2/32 */ /* HiTone = 4V = 15750Hz/2/4 */ /************************************************/ DISCRETE_SQUAREWFIX(DRAGRACE_LOTONE_SND, DRAGRACE_LOTONE_EN, 15750.0/2/32, 593.8, 50.0, 0, 0.0) DISCRETE_SQUAREWFIX(DRAGRACE_HITONE_SND, DRAGRACE_HITONE_EN, 15750.0/2/4, 593.8, 50.0, 0, 0.0) DISCRETE_ADDER2(DRAGRACE_TONE_SND, 1, DRAGRACE_LOTONE_SND, DRAGRACE_HITONE_SND) /************************************************/ /* Combine all 5 sound sources. */ /* Add some final gain to get to a good sound */ /* level. */ /************************************************/ DISCRETE_ADDER4(NODE_90, DRAGRACE_ATTRACT_EN, DRAGRACE_TONE_SND, DRAGRACE_MOTOR1_SND, DRAGRACE_EXPLODE1_SND, DRAGRACE_SCREECH1_SND) DISCRETE_ADDER4(NODE_91, DRAGRACE_ATTRACT_EN, DRAGRACE_TONE_SND, DRAGRACE_MOTOR2_SND, DRAGRACE_EXPLODE2_SND, DRAGRACE_SCREECH2_SND) DISCRETE_OUTPUT(NODE_90, 65534.0/(593.8+581.6+1000.0+57.6)) DISCRETE_OUTPUT(NODE_91, 65534.0/(593.8+581.6+1000.0+57.6)) DISCRETE_SOUND_END