diff options
Diffstat (limited to 'src/mame/audio/geebee.c')
-rw-r--r-- | src/mame/audio/geebee.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/src/mame/audio/geebee.c b/src/mame/audio/geebee.c index a30cb82cc94..59a51e537a1 100644 --- a/src/mame/audio/geebee.c +++ b/src/mame/audio/geebee.c @@ -50,28 +50,28 @@ WRITE8_DEVICE_HANDLER( geebee_sound_w ) if( state->m_sound_latch & 8 ) { /* - * R24 is 10k, Rb is 0, C57 is 1uF - * charge time t1 = 0.693 * (R24 + Rb) * C57 -> 0.22176s - * discharge time t2 = 0.693 * (Rb) * C57 -> 0 - * Then C33 is only charged via D6 (1N914), not discharged! - * Decay: - * discharge C33 (1uF) through R50 (22k) -> 0.14058s - */ + * R24 is 10k, Rb is 0, C57 is 1uF + * charge time t1 = 0.693 * (R24 + Rb) * C57 -> 0.22176s + * discharge time t2 = 0.693 * (Rb) * C57 -> 0 + * Then C33 is only charged via D6 (1N914), not discharged! + * Decay: + * discharge C33 (1uF) through R50 (22k) -> 0.14058s + */ attotime period = attotime::from_hz(32768) * 14058 / 100000; state->m_volume_timer->adjust(period, 0, period); } else { /* - * discharge only after R49 (100k) in the amplifier section, - * so the volume shouldn't very fast and only when the signal - * is gated through 6N (4066). - * I can only guess here that the decay should be slower, - * maybe half as fast? - */ + * discharge only after R49 (100k) in the amplifier section, + * so the volume shouldn't very fast and only when the signal + * is gated through 6N (4066). + * I can only guess here that the decay should be slower, + * maybe half as fast? + */ attotime period = attotime::from_hz(32768) * 29060 / 100000; state->m_volume_timer->adjust(period, 0, period); - } + } } static STREAM_UPDATE( geebee_sound_update ) @@ -147,7 +147,7 @@ const device_type GEEBEE = &device_creator<geebee_sound_device>; geebee_sound_device::geebee_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : device_t(mconfig, GEEBEE, "Gee Bee Custom", tag, owner, clock), - device_sound_interface(mconfig, *this) + device_sound_interface(mconfig, *this) { m_token = global_alloc_clear(geebee_sound_state); } @@ -180,5 +180,3 @@ void geebee_sound_device::sound_stream_update(sound_stream &stream, stream_sampl // should never get here fatalerror("sound_stream_update called; not applicable to legacy sound devices\n"); } - - |