diff options
Diffstat (limited to 'trunk/src/mame/audio/llander.c')
-rw-r--r-- | trunk/src/mame/audio/llander.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/trunk/src/mame/audio/llander.c b/trunk/src/mame/audio/llander.c new file mode 100644 index 00000000000..0c5f67b80be --- /dev/null +++ b/trunk/src/mame/audio/llander.c @@ -0,0 +1,96 @@ +/*************************************************************************** + + Lunar Lander Specific Sound Code + +***************************************************************************/ + +#include "emu.h" +#include "includes/asteroid.h" +#include "sound/discrete.h" + +/************************************************************************/ +/* Lunar Lander Sound System Analog emulation by K.Wilkins Nov 2000 */ +/* Questions/Suggestions to mame@dysfunction.demon.co.uk */ +/************************************************************************/ +#define LLANDER_TONE3K_EN NODE_01 +#define LLANDER_TONE6K_EN NODE_02 +#define LLANDER_THRUST_DATA NODE_03 +#define LLANDER_EXPLOD_EN NODE_04 +#define LLANDER_NOISE_RESET NODE_05 + +#define LLANDER_NOISE NODE_10 +#define LLANDER_TONE_3K_SND NODE_11 +#define LLANDER_TONE_6K_SND NODE_12 +#define LLANDER_THRUST_EXPLOD_SND NODE_13 + +static const discrete_lfsr_desc llander_lfsr = +{ + DISC_CLK_IS_FREQ, + 16, /* Bit Length */ + 0, /* Reset Value */ + 6, /* Use Bit 6 as XOR input 0 */ + 14, /* Use Bit 14 as XOR input 1 */ + DISC_LFSR_XNOR, /* Feedback stage1 is inverted XOR */ + DISC_LFSR_IN0, /* Feedback stage2 is just stage 1 output external feed not used */ + DISC_LFSR_REPLACE, /* Feedback stage3 replaces the shifted register contents */ + 0x000001, /* Everything is shifted into the first bit only */ + 0, /* Output not inverted */ + 14 /* Output bit */ +}; + +DISCRETE_SOUND_START(llander) + /************************************************/ + /* llander Effects Relataive Gain Table */ + /* */ + /* Effect V-ampIn Gain ratio Relative */ + /* Tone3k 4 10/390 9.2 */ + /* Tone6k 4 10/390 9.2 */ + /* Explode 3.8 10/6.8*2 1000.0 */ + /* Thrust 3.8 10/6.8*2 600.0 */ + /* NOTE: Thrust gain has to be tweaked, due to */ + /* the filter stage. */ + /************************************************/ + + /* NODE GAIN OFFSET INIT */ + DISCRETE_INPUTX_DATA(LLANDER_THRUST_DATA, 600.0/7*7.6, 0, 0) + DISCRETE_INPUT_LOGIC(LLANDER_TONE3K_EN) + DISCRETE_INPUT_LOGIC(LLANDER_TONE6K_EN) + DISCRETE_INPUT_LOGIC(LLANDER_EXPLOD_EN) + DISCRETE_INPUT_PULSE(LLANDER_NOISE_RESET, 1) + + DISCRETE_LFSR_NOISE(NODE_20, 1, LLANDER_NOISE_RESET, 12000, 1, 0, 0, &llander_lfsr) // 12KHz Noise source for thrust + DISCRETE_RCFILTER(LLANDER_NOISE, NODE_20, 2247, 1e-6) + + DISCRETE_SQUAREWFIX(LLANDER_TONE_3K_SND, LLANDER_TONE3K_EN, 3000, 9.2, 50, 0, 0) // 3KHz + + DISCRETE_SQUAREWFIX(LLANDER_TONE_6K_SND, LLANDER_TONE6K_EN, 6000, 9.2, 50, 0, 0) // 6KHz + + DISCRETE_MULTIPLY(NODE_30, LLANDER_NOISE, LLANDER_THRUST_DATA) // Mix in 12KHz Noise source for thrust + /* TBD - replace this line with a Sallen-Key Bandpass macro */ + DISCRETE_FILTER2(NODE_31, 1, NODE_30, 89.5, (1.0 / 7.6), DISC_FILTER_BANDPASS) + DISCRETE_MULTIPLY(NODE_32, NODE_30, 1000.0/600.0) // Explode adds original noise source onto filtered source + DISCRETE_ONOFF(NODE_33, LLANDER_EXPLOD_EN, NODE_32) + DISCRETE_ADDER2(NODE_34, 1, NODE_31, NODE_33) + /* TBD - replace this line with a Active Lowpass macro */ + DISCRETE_FILTER1(LLANDER_THRUST_EXPLOD_SND, 1, NODE_34, 560, DISC_FILTER_LOWPASS) + + DISCRETE_ADDER3(NODE_90, 1, LLANDER_TONE_3K_SND, LLANDER_TONE_6K_SND, LLANDER_THRUST_EXPLOD_SND) // Mix all four sound sources + DISCRETE_GAIN(NODE_91, NODE_90, 65534.0/(9.2+9.2+600+1000)) + + DISCRETE_OUTPUT(NODE_90, 65534.0/(9.2+9.2+600+1000)) // Take the output from the mixer +DISCRETE_SOUND_END + +WRITE8_DEVICE_HANDLER( llander_snd_reset_w ) +{ + /* Resets the LFSR that is used for the white noise generator */ + discrete_sound_w(device, LLANDER_NOISE_RESET, 0); /* Reset */ +} + +WRITE8_DEVICE_HANDLER( llander_sounds_w ) +{ + discrete_sound_w(device, LLANDER_THRUST_DATA, data & 0x07); /* Thrust volume */ + discrete_sound_w(device, LLANDER_TONE3K_EN, data & 0x10); /* Tone 3KHz enable */ + discrete_sound_w(device, LLANDER_TONE6K_EN, data & 0x20); /* Tone 6KHz enable */ + discrete_sound_w(device, LLANDER_EXPLOD_EN, data & 0x08); /* Explosion */ +} + |