diff options
Diffstat (limited to 'trunk/src/mame/audio/skydiver.c')
-rw-r--r-- | trunk/src/mame/audio/skydiver.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/trunk/src/mame/audio/skydiver.c b/trunk/src/mame/audio/skydiver.c new file mode 100644 index 00000000000..14b46b8cb72 --- /dev/null +++ b/trunk/src/mame/audio/skydiver.c @@ -0,0 +1,146 @@ +/************************************************************************* + + audio\skydiver.c + +*************************************************************************/ +#include "emu.h" +#include "includes/skydiver.h" +#include "sound/discrete.h" + + +/************************************************************************/ +/* skydiver Sound System Analog emulation */ +/* Jan 2004, Derrick Renaud */ +/************************************************************************/ + +static const discrete_555_desc skydiverWhistl555 = +{ + DISC_555_OUT_SQW | DISC_555_OUT_AC, + 5, // B+ voltage of 555 + DEFAULT_555_VALUES +}; + +static const discrete_lfsr_desc skydiver_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 */ + DISC_LFSR_FLAG_OUT_INVERT, /* Output is inverted, Active Low Reset */ + 15 /* Output bit */ +}; + +/* Nodes - Sounds */ +#define SKYDIVER_NOTE_SND NODE_11 +#define SKYDIVER_NOISE_SND NODE_12 +#define SKYDIVER_WHISTLE1_SND NODE_13 +#define SKYDIVER_WHISTLE2_SND NODE_14 + +DISCRETE_SOUND_START(skydiver) + /************************************************/ + /* skydiver Effects Relataive Gain Table */ + /* */ + /* Effect V-ampIn Gain ratio Relative */ + /* Note 3.8 3.8/260.5 1000.0 */ + /* Noise 3.8 3.8/680 383.1 */ + /* Whistle 5.0 5.0/1500 228.5 */ + /************************************************/ + + /************************************************/ + /* Input register mapping for skydiver */ + /************************************************/ + /* NODE GAIN OFFSET INIT */ + DISCRETE_INPUT_DATA (SKYDIVER_RANGE_DATA) + DISCRETE_INPUT_LOGIC (SKYDIVER_RANGE3_EN) + DISCRETE_INPUT_DATA (SKYDIVER_NOTE_DATA) + DISCRETE_INPUTX_DATA (SKYDIVER_NOISE_DATA, 383.1/15.0, 0.0, 0.0) + DISCRETE_INPUT_NOT (SKYDIVER_NOISE_RST) + DISCRETE_INPUT_LOGIC (SKYDIVER_WHISTLE1_EN) + DISCRETE_INPUT_LOGIC (SKYDIVER_WHISTLE2_EN) + DISCRETE_INPUT_LOGIC (SKYDIVER_OCT1_EN) + DISCRETE_INPUT_LOGIC (SKYDIVER_OCT2_EN) + DISCRETE_INPUT_LOGIC (SKYDIVER_SOUND_EN) + /************************************************/ + + /************************************************/ + /* The note generator has a selectable range */ + /* and selectable frequency. */ + /* The base frequency is */ + /* 12.096MHz / 2 / range / note freq / 2 */ + /* The final /2 is just to give a 50% duty, */ + /* so we can just start by 12.096MHz/4/range */ + /* The octave is selected by 3 bits selecting */ + /* 000 64H = 12096MHz / 2 / 128 */ + /* 001 32H = 12096MHz / 2 / 64 */ + /* 010 16H = 12096MHz / 2 / 32 */ + /* 011 8H = 12096MHz / 2 / 16 */ + /* 100 4H = 12096MHz / 2 / 8 */ + /* 101 2H = 12096MHz / 2 / 4 */ + /* 110 1H = 12096MHz / 2 / 2 */ + /* 111 6MHz = 12096MHz / 2 / 1 */ + /* We will convert the 3 range bits to a */ + /* divide value in the driver before sending */ + /* to the sound interface. */ + /* */ + /* note data: 0xff = off, */ + /* 0xfe = /2, */ + /* 0x00 = /256 */ + /* We will send the note data bit inverted to */ + /* sound interface so it is easier to work with.*/ + /* */ + /* The note generator is disabled by a low on */ + /* RANGE3. */ + /************************************************/ + // We will disable the divide if SKYDIVER_RANGE_DATA = 0 + DISCRETE_DIVIDE(NODE_20, SKYDIVER_RANGE_DATA, 12096000.0 /2.0 / 2.0, SKYDIVER_RANGE_DATA) + DISCRETE_ADDER2(NODE_21, 1, SKYDIVER_NOTE_DATA, 1) + // We will disable the divide if SKYDIVER_NOTE_DATA = 0 + DISCRETE_DIVIDE(NODE_22, SKYDIVER_NOTE_DATA, NODE_20, NODE_21) // freq + DISCRETE_SQUAREWAVE(SKYDIVER_NOTE_SND, SKYDIVER_RANGE3_EN, NODE_22, 1000.0, 50.0, 0, 0.0) + + /************************************************/ + /* Noise 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 binary weighted with 4 bits of */ + /* volume. */ + /************************************************/ + DISCRETE_LFSR_NOISE(SKYDIVER_NOISE_SND, SKYDIVER_NOISE_RST, SKYDIVER_NOISE_RST, 15750.0/2.0, SKYDIVER_NOISE_DATA, 0, 0, &skydiver_lfsr) + + /************************************************/ + /* Whistle circuit is a 555 capacitor charge */ + /* waveform. The original game pot varies from */ + /* 0-250k, 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_30, 250000, 50000, DISC_LINADJ, "WHISTLE1") /* R66 */ + DISCRETE_MULTADD(NODE_31, SKYDIVER_WHISTLE1_EN, 3.05-0.33, 0.33) + DISCRETE_RCDISC2(NODE_32, SKYDIVER_WHISTLE1_EN, NODE_31, 1.0, NODE_31, 68000.0, 2.2e-5) /* CV */ + DISCRETE_SWITCH(NODE_33, 1, SKYDIVER_OCT1_EN, 1e-8, 1e-8 + 3.3e-9) /* Cap C73 & C58 */ + DISCRETE_555_ASTABLE_CV(NODE_34, SKYDIVER_WHISTLE1_EN, 100000, NODE_30, NODE_33, NODE_32, &skydiverWhistl555) + DISCRETE_MULTIPLY(SKYDIVER_WHISTLE1_SND, NODE_34, 228.5/3.3) + + DISCRETE_ADJUSTMENT(NODE_35, 250000, 50000, DISC_LINADJ, "WHISTLE2") /* R65 */ + DISCRETE_MULTADD(NODE_36, SKYDIVER_WHISTLE2_EN, 3.05-0.33, 0.33) + DISCRETE_RCDISC2(NODE_37, SKYDIVER_WHISTLE2_EN, NODE_36, 1.0, NODE_36, 68000.0, 2.2e-5) /* CV */ + DISCRETE_SWITCH(NODE_38, 1, SKYDIVER_OCT2_EN, 1e-8, 1e-8 + 3.3e-9) /* Cap C72 & C59 */ + DISCRETE_555_ASTABLE_CV(NODE_39, SKYDIVER_WHISTLE2_EN, 100000, NODE_35, NODE_38, NODE_37, &skydiverWhistl555) + DISCRETE_MULTIPLY(SKYDIVER_WHISTLE2_SND, NODE_39, 228.5/3.3) + + /************************************************/ + /* Final mix and output. */ + /************************************************/ + DISCRETE_ADDER4(NODE_90, SKYDIVER_SOUND_EN, SKYDIVER_NOTE_SND, SKYDIVER_NOISE_SND, SKYDIVER_WHISTLE1_SND, SKYDIVER_WHISTLE2_SND) + + DISCRETE_OUTPUT(NODE_90, 65534.0/(1000.0 + 383.1 + 228.5 + 228.5)) +DISCRETE_SOUND_END |