diff options
Diffstat (limited to 'src/mame/audio/warpwarp.c')
-rw-r--r-- | src/mame/audio/warpwarp.c | 84 |
1 files changed, 41 insertions, 43 deletions
diff --git a/src/mame/audio/warpwarp.c b/src/mame/audio/warpwarp.c index a0095c32453..62367457f2f 100644 --- a/src/mame/audio/warpwarp.c +++ b/src/mame/audio/warpwarp.c @@ -10,7 +10,7 @@ #include "emu.h" #include "includes/warpwarp.h" -#define CLOCK_16H (18432000/3/2/16) +#define CLOCK_16H (18432000/3/2/16) #define CLOCK_1V (18432000/3/2/384) struct warpwarp_sound_state @@ -63,26 +63,26 @@ WRITE8_DEVICE_HANDLER( warpwarp_sound_w ) if( state->m_sound_latch & 8 ) { /* - * R85(?) is 10k, Rb is 0, C92 is 1uF - * charge time t1 = 0.693 * (R24 + Rb) * C57 -> 0.22176s - * discharge time t2 = 0.693 * (Rb) * C57 -> 0 - * C90(?) is only charged via D17 (1N914), no discharge! - * Decay: - * discharge C90(?) (1uF) through R13||R14 (22k||47k) - * 0.639 * 15k * 1uF -> 0.9585s - */ + * R85(?) is 10k, Rb is 0, C92 is 1uF + * charge time t1 = 0.693 * (R24 + Rb) * C57 -> 0.22176s + * discharge time t2 = 0.693 * (Rb) * C57 -> 0 + * C90(?) is only charged via D17 (1N914), no discharge! + * Decay: + * discharge C90(?) (1uF) through R13||R14 (22k||47k) + * 0.639 * 15k * 1uF -> 0.9585s + */ attotime period = attotime::from_hz(32768) * 95850 / 100000; state->m_sound_volume_timer->adjust(period, 0, period); } else { /* - * discharge only after R93 (100k) and through the 10k - * potentiometerin the amplifier section. - * 0.639 * 110k * 1uF -> 7.0290s - * ...but this is not very realistic for the game sound :( - * maybe there _is_ a discharge through the diode D17? - */ + * discharge only after R93 (100k) and through the 10k + * potentiometerin the amplifier section. + * 0.639 * 110k * 1uF -> 7.0290s + * ...but this is not very realistic for the game sound :( + * maybe there _is_ a discharge through the diode D17? + */ //attotime period = attotime::from_hz(32768) * 702900 / 100000; attotime period = attotime::from_hz(32768) * 191700 / 100000; state->m_sound_volume_timer->adjust(period, 0, period); @@ -114,25 +114,25 @@ WRITE8_DEVICE_HANDLER( warpwarp_music2_w ) if( state->m_music2_latch & 0x10 ) { /* - * Ra (R83?) is 10k, Rb is 0, C92 is 1uF - * charge time t1 = 0.693 * (Ra + Rb) * C -> 0.22176s - * discharge time is (nearly) zero, because Rb is zero - * C95(?) is only charged via D17, not discharged! - * Decay: - * discharge C95(?) (10uF) through R13||R14 (22k||47k) - * 0.639 * 15k * 10uF -> 9.585s - * ...I'm sure this is off by one number of magnitude :/ - */ + * Ra (R83?) is 10k, Rb is 0, C92 is 1uF + * charge time t1 = 0.693 * (Ra + Rb) * C -> 0.22176s + * discharge time is (nearly) zero, because Rb is zero + * C95(?) is only charged via D17, not discharged! + * Decay: + * discharge C95(?) (10uF) through R13||R14 (22k||47k) + * 0.639 * 15k * 10uF -> 9.585s + * ...I'm sure this is off by one number of magnitude :/ + */ attotime period = attotime::from_hz(32768) * 95850 / 100000; state->m_music_volume_timer->adjust(period, 0, period); } else { /* - * discharge through R14 (47k), - * discharge C95(?) (10uF) through R14 (47k) - * 0.639 * 47k * 10uF -> 30.033s - */ + * discharge through R14 (47k), + * discharge C95(?) (10uF) through R14 (47k) + * 0.639 * 47k * 10uF -> 30.033s + */ //attotime period = attotime::from_hz(32768) * 3003300 / 100000; attotime period = attotime::from_hz(32768) * 300330 / 100000; state->m_music_volume_timer->adjust(period, 0, period); @@ -150,18 +150,18 @@ static STREAM_UPDATE( warpwarp_sound_update ) *buffer++ = (state->m_sound_signal + state->m_music_signal) / 2; /* - * The music signal is selected at a rate of 2H (1.536MHz) from the - * four bits of a 4 bit binary counter which is clocked with 16H, - * which is 192kHz, and is divided by 4 times (64 - music1_latch). - * 0 = 256 steps -> 750 Hz - * 1 = 252 steps -> 761.9 Hz - * ... - * 32 = 128 steps -> 1500 Hz - * ... - * 48 = 64 steps -> 3000 Hz - * ... - * 63 = 4 steps -> 48 kHz - */ + * The music signal is selected at a rate of 2H (1.536MHz) from the + * four bits of a 4 bit binary counter which is clocked with 16H, + * which is 192kHz, and is divided by 4 times (64 - music1_latch). + * 0 = 256 steps -> 750 Hz + * 1 = 252 steps -> 761.9 Hz + * ... + * 32 = 128 steps -> 1500 Hz + * ... + * 48 = 64 steps -> 3000 Hz + * ... + * 63 = 4 steps -> 48 kHz + */ state->m_mcarry -= CLOCK_16H / (4 * (64 - state->m_music1_latch)); while( state->m_mcarry < 0 ) { @@ -245,7 +245,7 @@ const device_type WARPWARP = &device_creator<warpwarp_sound_device>; warpwarp_sound_device::warpwarp_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : device_t(mconfig, WARPWARP, "Warp Warp Custom", tag, owner, clock), - device_sound_interface(mconfig, *this) + device_sound_interface(mconfig, *this) { m_token = global_alloc_clear(warpwarp_sound_state); } @@ -278,5 +278,3 @@ void warpwarp_sound_device::sound_stream_update(sound_stream &stream, stream_sam // should never get here fatalerror("sound_stream_update called; not applicable to legacy sound devices\n"); } - - |