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-rw-r--r--src/mame/audio/llander.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/src/mame/audio/llander.c b/src/mame/audio/llander.c
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+++ b/src/mame/audio/llander.c
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+/***************************************************************************
+
+ Lunar Lander Specific Sound Code
+
+***************************************************************************/
+
+#include "driver.h"
+#include "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, 1, 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, 1, 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, LLANDER_EXPLOD_EN, NODE_30, 1000.0/600.0) // Explode adds original noise source onto filtered source
+ DISCRETE_ADDER2(NODE_33, 1, NODE_31, NODE_32)
+ /* TBD - replace this line with a Active Lowpass macro */
+ DISCRETE_FILTER1(LLANDER_THRUST_EXPLOD_SND, 1, NODE_33, 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_HANDLER( llander_snd_reset_w )
+{
+ /* Resets the LFSR that is used for the white noise generator */
+ discrete_sound_w(LLANDER_NOISE_RESET, 0); /* Reset */
+}
+
+WRITE8_HANDLER( llander_sounds_w )
+{
+ discrete_sound_w(LLANDER_THRUST_DATA, data & 0x07); /* Thrust volume */
+ discrete_sound_w(LLANDER_TONE3K_EN, data & 0x10); /* Tone 3KHz enable */
+ discrete_sound_w(LLANDER_TONE6K_EN, data & 0x20); /* Tone 6KHz enable */
+ discrete_sound_w(LLANDER_EXPLOD_EN, data & 0x08); /* Explosion */
+}
+