1 // license:BSD-3-Clause
2 // copyright-holders:K.Wilkins
3 /***************************************************************************
4
5 Lunar Lander Specific Sound Code
6
7 ***************************************************************************/
8
9 #include "emu.h"
10 #include "includes/asteroid.h"
11 #include "sound/discrete.h"
12 #include "speaker.h"
13
14 /************************************************************************/
15 /* Lunar Lander Sound System Analog emulation by K.Wilkins Nov 2000 */
16 /* Questions/Suggestions to mame@esplexo.co.uk */
17 /************************************************************************/
18 #define LLANDER_TONE3K_EN NODE_01
19 #define LLANDER_TONE6K_EN NODE_02
20 #define LLANDER_THRUST_DATA NODE_03
21 #define LLANDER_EXPLOD_EN NODE_04
22 #define LLANDER_NOISE_RESET NODE_05
23
24 #define LLANDER_NOISE NODE_10
25 #define LLANDER_TONE_3K_SND NODE_11
26 #define LLANDER_TONE_6K_SND NODE_12
27 #define LLANDER_THRUST_EXPLOD_SND NODE_13
28
29 static const discrete_lfsr_desc llander_lfsr =
30 {
31 DISC_CLK_IS_FREQ,
32 16, /* Bit Length */
33 0, /* Reset Value */
34 6, /* Use Bit 6 as XOR input 0 */
35 14, /* Use Bit 14 as XOR input 1 */
36 DISC_LFSR_XNOR, /* Feedback stage1 is inverted XOR */
37 DISC_LFSR_IN0, /* Feedback stage2 is just stage 1 output external feed not used */
38 DISC_LFSR_REPLACE, /* Feedback stage3 replaces the shifted register contents */
39 0x000001, /* Everything is shifted into the first bit only */
40 0, /* Output not inverted */
41 14 /* Output bit */
42 };
43
44 static DISCRETE_SOUND_START(llander_discrete)
45 /************************************************/
46 /* llander Effects Relataive Gain Table */
47 /* */
48 /* Effect V-ampIn Gain ratio Relative */
49 /* Tone3k 4 10/390 9.2 */
50 /* Tone6k 4 10/390 9.2 */
51 /* Explode 3.8 10/6.8*2 1000.0 */
52 /* Thrust 3.8 10/6.8*2 600.0 */
53 /* NOTE: Thrust gain has to be tweaked, due to */
54 /* the filter stage. */
55 /************************************************/
56
57 /* NODE GAIN OFFSET INIT */
58 DISCRETE_INPUTX_DATA(LLANDER_THRUST_DATA, 600.0/7*7.6, 0, 0)
DISCRETE_INPUT_LOGIC(LLANDER_TONE3K_EN)59 DISCRETE_INPUT_LOGIC(LLANDER_TONE3K_EN)
60 DISCRETE_INPUT_LOGIC(LLANDER_TONE6K_EN)
61 DISCRETE_INPUT_LOGIC(LLANDER_EXPLOD_EN)
62 DISCRETE_INPUT_PULSE(LLANDER_NOISE_RESET, 1)
63
64 DISCRETE_LFSR_NOISE(NODE_20, 1, LLANDER_NOISE_RESET, 12000, 1, 0, 0, &llander_lfsr) // 12KHz Noise source for thrust
65 DISCRETE_RCFILTER(LLANDER_NOISE, NODE_20, 2247, 1e-6)
66
67 DISCRETE_SQUAREWFIX(LLANDER_TONE_3K_SND, LLANDER_TONE3K_EN, 3000, 9.2, 50, 0, 0) // 3KHz
68
69 DISCRETE_SQUAREWFIX(LLANDER_TONE_6K_SND, LLANDER_TONE6K_EN, 6000, 9.2, 50, 0, 0) // 6KHz
70
71 DISCRETE_MULTIPLY(NODE_30, LLANDER_NOISE, LLANDER_THRUST_DATA) // Mix in 12KHz Noise source for thrust
72 /* TBD - replace this line with a Sallen-Key Bandpass macro */
73 DISCRETE_FILTER2(NODE_31, 1, NODE_30, 89.5, (1.0 / 7.6), DISC_FILTER_BANDPASS)
74 DISCRETE_MULTIPLY(NODE_32, NODE_30, 1000.0/600.0) // Explode adds original noise source onto filtered source
75 DISCRETE_ONOFF(NODE_33, LLANDER_EXPLOD_EN, NODE_32)
76 DISCRETE_ADDER2(NODE_34, 1, NODE_31, NODE_33)
77 /* TBD - replace this line with a Active Lowpass macro */
78 DISCRETE_FILTER1(LLANDER_THRUST_EXPLOD_SND, 1, NODE_34, 560, DISC_FILTER_LOWPASS)
79
80 DISCRETE_ADDER3(NODE_90, 1, LLANDER_TONE_3K_SND, LLANDER_TONE_6K_SND, LLANDER_THRUST_EXPLOD_SND) // Mix all four sound sources
81 DISCRETE_GAIN(NODE_91, NODE_90, 65534.0/(9.2+9.2+600+1000))
82
83 DISCRETE_OUTPUT(NODE_90, 65534.0/(9.2+9.2+600+1000)) // Take the output from the mixer
84 DISCRETE_SOUND_END
85
86 void asteroid_state::llander_snd_reset_w(uint8_t data)
87 {
88 /* Resets the LFSR that is used for the white noise generator */
89 m_discrete->write(LLANDER_NOISE_RESET, 0); /* Reset */
90 }
91
llander_sounds_w(uint8_t data)92 void asteroid_state::llander_sounds_w(uint8_t data)
93 {
94 m_discrete->write(LLANDER_THRUST_DATA, data & 0x07); /* Thrust volume */
95 m_discrete->write(LLANDER_TONE3K_EN, data & 0x10); /* Tone 3KHz enable */
96 m_discrete->write(LLANDER_TONE6K_EN, data & 0x20); /* Tone 6KHz enable */
97 m_discrete->write(LLANDER_EXPLOD_EN, data & 0x08); /* Explosion */
98 }
99
100
llander_sound(machine_config & config)101 void asteroid_state::llander_sound(machine_config &config)
102 {
103 SPEAKER(config, "mono").front_center();
104
105 DISCRETE(config, m_discrete, llander_discrete).add_route(ALL_OUTPUTS, "mono", 1.0);
106 }
107