diff options
Diffstat (limited to 'src/mame/audio/orbit.c')
-rw-r--r-- | src/mame/audio/orbit.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/src/mame/audio/orbit.c b/src/mame/audio/orbit.c new file mode 100644 index 00000000000..5ac7de6acd8 --- /dev/null +++ b/src/mame/audio/orbit.c @@ -0,0 +1,130 @@ +/************************************************************************* + + audio\orbit.c + +*************************************************************************/ +#include "driver.h" +#include "orbit.h" +#include "sound/discrete.h" + +/************************************* + * + * Write handlers + * + *************************************/ + +WRITE8_HANDLER( orbit_note_w ) +{ + discrete_sound_w(ORBIT_NOTE_FREQ, (~data) & 0xff); +} + +WRITE8_HANDLER( orbit_note_amp_w ) +{ + discrete_sound_w(ORBIT_ANOTE1_AMP, data & 0x0f); + discrete_sound_w(ORBIT_ANOTE2_AMP, data >> 4); +} + +WRITE8_HANDLER( orbit_noise_amp_w ) +{ + discrete_sound_w(ORBIT_NOISE1_AMP, data & 0x0f); + discrete_sound_w(ORBIT_NOISE2_AMP, data >> 4); +} + +WRITE8_HANDLER( orbit_noise_rst_w ) +{ + discrete_sound_w(ORBIT_NOISE_EN, 0); +} + + +/************************************************************************/ +/* orbit Sound System Analog emulation */ +/************************************************************************/ + +static const discrete_lfsr_desc orbit_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 ORBIT_NOISE NODE_10 +#define ORBIT_NOISE1_SND NODE_11 +#define ORBIT_NOISE2_SND NODE_12 +#define ORBIT_ANOTE1_SND NODE_13 +#define ORBIT_ANOTE2_SND NODE_14 +#define ORBIT_WARNING_SND NODE_15 + +DISCRETE_SOUND_START(orbit) + /************************************************/ + /* orbit Effects Relataive Gain Table */ + /* */ + /* Effect V-ampIn Gain ratio Relative */ + /* Note 3.8 10/(20.1+.47+.55) 962.1 */ + /* Warning 3.8 10/(20.1+6.8) 755.4 */ + /* Noise 3.8 10/(20.1+.22) 1000.0 */ + /************************************************/ + + /************************************************/ + /* Input register mapping for orbit */ + /************************************************/ + /* NODE GAIN OFFSET INIT */ + DISCRETE_INPUT_DATA (ORBIT_NOTE_FREQ) + DISCRETE_INPUTX_DATA(ORBIT_ANOTE1_AMP, 962.1/15, 0, 0.0) + DISCRETE_INPUTX_DATA(ORBIT_ANOTE2_AMP, 962.1/15, 0, 0.0) + DISCRETE_INPUTX_DATA(ORBIT_NOISE1_AMP, 1000.0/15*10, 0, 0.0) + DISCRETE_INPUTX_DATA(ORBIT_NOISE2_AMP, 1000.0/15*10, 0, 0.0) + DISCRETE_INPUT_LOGIC(ORBIT_WARNING_EN) + DISCRETE_INPUT_PULSE(ORBIT_NOISE_EN, 1) + + /************************************************/ + /* Warning is just a triggered 2V signal */ + /************************************************/ + DISCRETE_SQUAREWFIX(ORBIT_WARNING_SND, ORBIT_WARNING_EN, 15750.0/4, 755.4, 50.0, 0, 0.0) + + /************************************************/ + /* Noise effect is variable amplitude, filtered */ + /* random noise. */ + /* LFSR clk = 32V= 15750.0Hz/2/32 */ + /************************************************/ + DISCRETE_LFSR_NOISE(ORBIT_NOISE, ORBIT_NOISE_EN, ORBIT_NOISE_EN, 15750.0/2/32, 1, 0, 0, &orbit_lfsr) + DISCRETE_MULTIPLY(NODE_20, 1, ORBIT_NOISE, ORBIT_NOISE1_AMP) + DISCRETE_MULTIPLY(NODE_21, 1, ORBIT_NOISE, ORBIT_NOISE2_AMP) + DISCRETE_FILTER2(ORBIT_NOISE1_SND, 1, NODE_20, 160.0, (1.0 / 10.0), DISC_FILTER_BANDPASS) + DISCRETE_FILTER2(ORBIT_NOISE2_SND, 1, NODE_21, 160.0, (1.0 / 10.0), DISC_FILTER_BANDPASS) + + /************************************************/ + /* Note sound is created by a divider circuit. */ + /* The master clock is the 64H signal, which is */ + /* 12.096MHz/256. This is then sent to a */ + /* preloadable 8 bit counter, which loads the */ + /* value from NOTELD when overflowing from 0xFF */ + /* to 0x00. Therefore it divides by 2 (NOTELD */ + /* = FE) to 256 (NOTELD = 00). */ + /* There is also a final /2 stage. */ + /* Note that there is no music disable line. */ + /* When there is no music, the game sets the */ + /* oscillator to 0Hz. (NOTELD = FF) */ + /************************************************/ + DISCRETE_ADDER2(NODE_30, 1, ORBIT_NOTE_FREQ, 1) /* To get values of 1 - 256 */ + DISCRETE_DIVIDE(NODE_31, 1, 12096000.0/256/2, NODE_30) + DISCRETE_SQUAREWAVE(ORBIT_ANOTE1_SND, ORBIT_NOTE_FREQ, NODE_31, ORBIT_ANOTE1_AMP, 50.0, 0, 0.0) /* NOTE=FF Disables audio */ + DISCRETE_SQUAREWAVE(ORBIT_ANOTE2_SND, ORBIT_NOTE_FREQ, NODE_31, ORBIT_ANOTE2_AMP, 50.0, 0, 0.0) /* NOTE=FF Disables audio */ + + /************************************************/ + /* Final mix and output. */ + /************************************************/ + DISCRETE_ADDER3(NODE_90, 1, ORBIT_WARNING_SND, ORBIT_NOISE1_SND, ORBIT_ANOTE1_SND) + DISCRETE_ADDER3(NODE_91, 1, ORBIT_WARNING_SND, ORBIT_NOISE2_SND, ORBIT_ANOTE2_SND) + + DISCRETE_OUTPUT(NODE_90, 65534.0/(962.1+755.4+1000.0)) + DISCRETE_OUTPUT(NODE_91, 65534.0/(962.1+755.4+1000.0)) +DISCRETE_SOUND_END |