diff options
Diffstat (limited to 'trunk/src/mame/audio/nitedrvr.c')
-rw-r--r-- | trunk/src/mame/audio/nitedrvr.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/trunk/src/mame/audio/nitedrvr.c b/trunk/src/mame/audio/nitedrvr.c new file mode 100644 index 00000000000..7537b2cb9bd --- /dev/null +++ b/trunk/src/mame/audio/nitedrvr.c @@ -0,0 +1,146 @@ +/************************************************************************* + + audio\nitedrvr.c + +*************************************************************************/ +#include "emu.h" +#include "includes/nitedrvr.h" +#include "sound/discrete.h" + + +/* Discrete Sound Emulation */ + +static const discrete_lfsr_desc nitedrvr_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 NITEDRVR_NOISE NODE_10 +#define NITEDRVR_BANG_SND NODE_11 +#define NITEDRVR_MOTOR_SND NODE_12 +#define NITEDRVR_SCREECH1_SND NODE_13 +#define NITEDRVR_SCREECH2_SND NODE_14 + +DISCRETE_SOUND_START(nitedrvr) + /************************************************/ + /* nitedrvr Effects Relataive Gain Table */ + /* */ + /* Effect V-ampIn Gain ratio Relative */ + /* Bang 3.8 5/(5+6.8) 1000.0 */ + /* Motor 3.8 5/(5+10) 786.7 */ + /* Screech1 3.8 5/(5+47) 226.9 */ + /* Screech2 3.8 5/(5+47) 226.9 */ + /************************************************/ + + /************************************************/ + /* Input register mapping for nitedrvr */ + /************************************************/ + /* NODE GAIN OFFSET INIT */ + DISCRETE_INPUTX_DATA (NITEDRVR_BANG_DATA, 1000.0/15, 0.0, 0.0) + DISCRETE_INPUT_LOGIC (NITEDRVR_SKID1_EN) + DISCRETE_INPUT_LOGIC (NITEDRVR_SKID2_EN) + DISCRETE_INPUTX_DATA (NITEDRVR_MOTOR_DATA, -1, 0x0f, 0) + DISCRETE_INPUT_LOGIC (NITEDRVR_CRASH_EN) + DISCRETE_INPUT_NOT (NITEDRVR_ATTRACT_EN) + + /************************************************/ + /* NOTE: Motor circuit is a rip from Sprint for */ + /* now. This will have to be converted to 566. */ + /* */ + /* 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 */ + /************************************************/ + DISCRETE_RCFILTER(NODE_20, NITEDRVR_MOTOR_DATA, 123037, 2.2e-6) + DISCRETE_ADJUSTMENT(NODE_21, (214.0-27.0)/12/31, (4416.0-27.0)/12/31, DISC_LOGADJ, "MOTOR") + 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, (786.7/3), 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, (786.7/3), 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, (786.7/3), 100.0/3, 0, 360.0/3) + DISCRETE_RCFILTER(NODE_31, NODE_30, 10000, 1e-7) + + DISCRETE_ADDER3(NITEDRVR_MOTOR_SND, NITEDRVR_ATTRACT_EN, NODE_25, NODE_28, NODE_31) + + /************************************************/ + /* Bang circuit is built around a noise */ + /* generator built from 2 shift registers that */ + /* are clocked by the 4V signal. */ + /* 4V = HSYNC/2/4 */ + /* = 15750/2/4 */ + /* Output is integrated to apply decay. */ + /************************************************/ + DISCRETE_LFSR_NOISE(NITEDRVR_NOISE, NITEDRVR_CRASH_EN, NITEDRVR_CRASH_EN, 15750.0/2/4, 1.0, 0, 0, &nitedrvr_lfsr) + + DISCRETE_MULTIPLY(NODE_62, NITEDRVR_NOISE, NITEDRVR_BANG_DATA) + DISCRETE_RCFILTER(NITEDRVR_BANG_SND, NODE_62, 545.6, 3.3e-7) + + /************************************************/ + /* Skid circuits ripped from other drivers */ + /* for now. */ + /* */ + /* 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, NITEDRVR_NOISE) + DISCRETE_RCFILTER(NODE_71, NODE_70, 1000, 1e-5) + DISCRETE_MULTADD(NODE_72, NODE_71, 940.0-630.0, ((940.0-630.0)/2)+630.0) + DISCRETE_SQUAREWAVE(NITEDRVR_SCREECH1_SND, NITEDRVR_SKID1_EN, NODE_72, 226.9, 31.5, 0, 0.0) + + DISCRETE_MULTADD(NODE_75, NODE_71, 1380.0-626.0, 626.0+((1380.0-626.0)/2)) /* Frequency */ + DISCRETE_MULTADD(NODE_76, NODE_71, 32.0-13.0, 13.0+((32.0-13.0)/2)) /* Duty */ + DISCRETE_SQUAREWAVE(NITEDRVR_SCREECH2_SND, NITEDRVR_SKID2_EN, NODE_75, 226.9, NODE_76, 0, 0.0) + + /************************************************/ + /* Combine all sound sources. */ + /* Add some final gain to get to a good sound */ + /* level. */ + /************************************************/ + DISCRETE_ADDER4(NODE_90, 1, NITEDRVR_MOTOR_SND, NITEDRVR_BANG_SND, NITEDRVR_SCREECH1_SND, NITEDRVR_SCREECH2_SND) + + DISCRETE_OUTPUT(NODE_90, 65534.0/(786.7+1000.0+226.9)) +DISCRETE_SOUND_END |