// 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(space, NODE_RELATIVE(CANYON_MOTOR1_DATA, (offset & 0x01)), data & 0x0f);
}
WRITE8_MEMBER(canyon_state::canyon_explode_w)
{
m_discrete->write(space, 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