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-rw-r--r--trunk/src/mame/audio/redbaron.c247
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);