diff options
Diffstat (limited to 'trunk/src/mame/audio/redbaron.c')
-rw-r--r-- | trunk/src/mame/audio/redbaron.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/trunk/src/mame/audio/redbaron.c b/trunk/src/mame/audio/redbaron.c new file mode 100644 index 00000000000..c32135d3bca --- /dev/null +++ b/trunk/src/mame/audio/redbaron.c @@ -0,0 +1,247 @@ +/************************************************************************* + + Atari Red Baron hardware + +*************************************************************************/ +/* + + Red Baron sound notes: + bit function + 7-4 explosion volume + 3 start led + 2 shot (machine gun sound) + 1 squeal (nosedive sound) + 0 POTSEL (rb_input_select) +*/ + +#include "emu.h" +#include "includes/bzone.h" +#include "sound/pokey.h" + +#define OUTPUT_RATE (48000) + +typedef struct _redbaron_sound_state redbaron_sound_state; +struct _redbaron_sound_state +{ + INT16 *m_vol_lookup; + + INT16 m_vol_crash[16]; + + sound_stream *m_channel; + int m_latch; + int m_poly_counter; + int m_poly_shift; + + int m_filter_counter; + + int m_crash_amp; + int m_shot_amp; + int m_shot_amp_counter; + + int m_squeal_amp; + int m_squeal_amp_counter; + int m_squeal_off_counter; + int m_squeal_on_counter; + int m_squeal_out; +}; + +INLINE redbaron_sound_state *get_safe_token(device_t *device) +{ + assert(device != NULL); + assert(device->type() == REDBARON); + + return (redbaron_sound_state *)downcast<legacy_device_base *>(device)->token(); +} + + +WRITE8_DEVICE_HANDLER( redbaron_sounds_w ) +{ + redbaron_sound_state *state = get_safe_token(device); + + /* If sound is off, don't bother playing samples */ + if( data == state->m_latch ) + return; + + state->m_channel->update(); + state->m_latch = data; +} + +#ifdef UNUSED_FUNCTION +WRITE8_DEVICE_HANDLER( redbaron_pokey_w ) +{ + redbaron_sound_state *state = get_safe_token(device); + + if( state->m_latch & 0x20 ) + pokey_w(device, offset, data); +} +#endif + +static STREAM_UPDATE( redbaron_sound_update ) +{ + redbaron_sound_state *state = get_safe_token(device); + stream_sample_t *buffer = outputs[0]; + while( samples-- ) + { + int sum = 0; + + /* polynome shifter E5 and F4 (LS164) clocked with 12kHz */ + state->m_poly_counter -= 12000; + while( state->m_poly_counter <= 0 ) + { + state->m_poly_counter += OUTPUT_RATE; + if( ((state->m_poly_shift & 0x0001) == 0) == ((state->m_poly_shift & 0x4000) == 0) ) + state->m_poly_shift = (state->m_poly_shift << 1) | 1; + else + state->m_poly_shift <<= 1; + } + + /* What is the exact low pass filter frequency? */ + state->m_filter_counter -= 330; + while( state->m_filter_counter <= 0 ) + { + state->m_filter_counter += OUTPUT_RATE; + state->m_crash_amp = (state->m_poly_shift & 1) ? state->m_latch >> 4 : 0; + } + /* mix crash sound at 35% */ + sum += state->m_vol_crash[state->m_crash_amp] * 35 / 100; + + /* shot not active: charge C32 (0.1u) */ + if( (state->m_latch & 0x04) == 0 ) + state->m_shot_amp = 32767; + else + if( (state->m_poly_shift & 0x8000) == 0 ) + { + if( state->m_shot_amp > 0 ) + { + /* discharge C32 (0.1u) through R26 (33k) + R27 (15k) + * 0.68 * C32 * (R26 + R27) = 3264us + */ +// #define C32_DISCHARGE_TIME (int)(32767 / 0.003264); + /* I think this is to short. Is C32 really 1u? */ + #define C32_DISCHARGE_TIME (int)(32767 / 0.03264); + state->m_shot_amp_counter -= C32_DISCHARGE_TIME; + while( state->m_shot_amp_counter <= 0 ) + { + state->m_shot_amp_counter += OUTPUT_RATE; + if( --state->m_shot_amp == 0 ) + break; + } + /* mix shot sound at 35% */ + sum += state->m_vol_lookup[state->m_shot_amp] * 35 / 100; + } + } + + + if( (state->m_latch & 0x02) == 0 ) + state->m_squeal_amp = 0; + else + { + if( state->m_squeal_amp < 32767 ) + { + /* charge C5 (22u) over R3 (68k) and CR1 (1N914) + * time = 0.68 * C5 * R3 = 1017280us + */ + #define C5_CHARGE_TIME (int)(32767 / 1.01728); + state->m_squeal_amp_counter -= C5_CHARGE_TIME; + while( state->m_squeal_amp_counter <= 0 ) + { + state->m_squeal_amp_counter += OUTPUT_RATE; + if( ++state->m_squeal_amp == 32767 ) + break; + } + } + + if( state->m_squeal_out ) + { + /* NE555 setup as pulse position modulator + * C = 0.01u, Ra = 33k, Rb = 47k + * frequency = 1.44 / ((33k + 2*47k) * 0.01u) = 1134Hz + * modulated by squeal_amp + */ + state->m_squeal_off_counter -= (1134 + 1134 * state->m_squeal_amp / 32767) / 3; + while( state->m_squeal_off_counter <= 0 ) + { + state->m_squeal_off_counter += OUTPUT_RATE; + state->m_squeal_out = 0; + } + } + else + { + state->m_squeal_on_counter -= 1134; + while( state->m_squeal_on_counter <= 0 ) + { + state->m_squeal_on_counter += OUTPUT_RATE; + state->m_squeal_out = 1; + } + } + } + + /* mix sequal sound at 40% */ + if( state->m_squeal_out ) + sum += 32767 * 40 / 100; + + *buffer++ = sum; + } +} + +static DEVICE_START( redbaron_sound ) +{ + redbaron_sound_state *state = get_safe_token(device); + int i; + + state->m_vol_lookup = auto_alloc_array(device->machine(), INT16, 32768); + for( i = 0; i < 0x8000; i++ ) + state->m_vol_lookup[0x7fff-i] = (INT16) (0x7fff/exp(1.0*i/4096)); + + for( i = 0; i < 16; i++ ) + { + /* r0 = R18 and R24, r1 = open */ + double r0 = 1.0/(5600 + 680), r1 = 1/6e12; + + /* R14 */ + if( i & 1 ) + r1 += 1.0/8200; + else + r0 += 1.0/8200; + /* R15 */ + if( i & 2 ) + r1 += 1.0/3900; + else + r0 += 1.0/3900; + /* R16 */ + if( i & 4 ) + r1 += 1.0/2200; + else + r0 += 1.0/2200; + /* R17 */ + if( i & 8 ) + r1 += 1.0/1000; + else + r0 += 1.0/1000; + r0 = 1.0/r0; + r1 = 1.0/r1; + state->m_vol_crash[i] = 32767 * r0 / (r0 + r1); + } + + state->m_channel = device->machine().sound().stream_alloc(*device, 0, 1, OUTPUT_RATE, 0, redbaron_sound_update); +} + + +DEVICE_GET_INFO( redbaron_sound ) +{ + switch (state) + { + /* --- the following bits of info are returned as 64-bit signed integers --- */ + case DEVINFO_INT_TOKEN_BYTES: info->i = sizeof(redbaron_sound_state); break; + + /* --- the following bits of info are returned as pointers to data or functions --- */ + case DEVINFO_FCT_START: info->start = DEVICE_START_NAME(redbaron_sound);break; + + /* --- the following bits of info are returned as NULL-terminated strings --- */ + case DEVINFO_STR_NAME: strcpy(info->s, "Red Baron Custom"); break; + case DEVINFO_STR_SOURCE_FILE: strcpy(info->s, __FILE__); break; + } +} + + +DEFINE_LEGACY_SOUND_DEVICE(REDBARON, redbaron_sound); |