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Diffstat (limited to 'src/mame/audio/meadows.cpp')
-rw-r--r-- | src/mame/audio/meadows.cpp | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/src/mame/audio/meadows.cpp b/src/mame/audio/meadows.cpp new file mode 100644 index 00000000000..48836a9975c --- /dev/null +++ b/src/mame/audio/meadows.cpp @@ -0,0 +1,116 @@ +// license:GPL-2.0+ +// copyright-holders:Juergen Buchmueller +/*************************************************************************** + meadows.c + Sound handler + Dead Eye, Gypsy Juggler + + J. Buchmueller, June '98 +****************************************************************************/ + +#include "emu.h" +#include "cpu/s2650/s2650.h" +#include "includes/meadows.h" +#include "sound/samples.h" +#include "sound/dac.h" + + + +#define BASE_CLOCK 5000000 +#define BASE_CTR1 (BASE_CLOCK / 256) +#define BASE_CTR2 (BASE_CLOCK / 32) + +#define DIV2OR4_CTR2 0x01 +#define ENABLE_CTR2 0x02 +#define ENABLE_DAC 0x04 +#define ENABLE_CTR1 0x08 + +static const INT16 waveform[2] = { -120*256, 120*256 }; + +/************************************/ +/* Sound handler start */ +/************************************/ +SAMPLES_START_CB_MEMBER(meadows_state::meadows_sh_start) +{ + m_0c00 = m_0c01 = m_0c02 = m_0c03 = 0; + m_dac_data = 0; + m_dac_enable = 0; + m_channel = 0; + m_freq1 = m_freq2 = 1000; + m_latched_0c01 = m_latched_0c02 = m_latched_0c03 = 0; + + m_samples->set_volume(0,0); + m_samples->start_raw(0,waveform,ARRAY_LENGTH(waveform),m_freq1,true); + m_samples->set_volume(1,0); + m_samples->start_raw(1,waveform,ARRAY_LENGTH(waveform),m_freq2,true); +} + +/************************************/ +/* Sound handler update */ +/************************************/ +void meadows_state::meadows_sh_update() +{ + int preset, amp; + + if (m_latched_0c01 != m_0c01 || m_latched_0c03 != m_0c03) + { + /* amplitude is a combination of the upper 4 bits of 0c01 */ + /* and bit 4 merged from S2650's flag output */ + amp = ((m_0c03 & ENABLE_CTR1) == 0) ? 0 : (m_0c01 & 0xf0) >> 1; + if( m_maincpu->state_int(S2650_FO) ) + amp += 0x80; + /* calculate frequency for counter #1 */ + /* bit 0..3 of 0c01 are ctr preset */ + preset = (m_0c01 & 15) ^ 15; + if (preset) + m_freq1 = BASE_CTR1 / (preset + 1); + else amp = 0; + logerror("meadows ctr1 channel #%d preset:%3d freq:%5d amp:%d\n", m_channel, preset, m_freq1, amp); + m_samples->set_frequency(0, m_freq1 * sizeof(waveform)/2); + m_samples->set_volume(0,amp/255.0); + } + + if (m_latched_0c02 != m_0c02 || m_latched_0c03 != m_0c03) + { + /* calculate frequency for counter #2 */ + /* 0c02 is ctr preset, 0c03 bit 0 enables division by 2 */ + amp = ((m_0c03 & ENABLE_CTR2) != 0) ? 0xa0 : 0; + preset = m_0c02 ^ 0xff; + if (preset) + { + m_freq2 = BASE_CTR2 / (preset + 1) / 2; + if ((m_0c03 & DIV2OR4_CTR2) == 0) + m_freq2 >>= 1; + } + else amp = 0; + logerror("meadows ctr2 channel #%d preset:%3d freq:%5d amp:%d\n", m_channel+1, preset, m_freq2, amp); + m_samples->set_frequency(1, m_freq2 * sizeof(waveform)); + m_samples->set_volume(1,amp/255.0); + } + + if (m_latched_0c03 != m_0c03) + { + m_dac_enable = m_0c03 & ENABLE_DAC; + + if (m_dac_enable) + m_dac->write_unsigned8(m_dac_data); + else + m_dac->write_unsigned8(0); + } + + m_latched_0c01 = m_0c01; + m_latched_0c02 = m_0c02; + m_latched_0c03 = m_0c03; +} + +/************************************/ +/* Write DAC value */ +/************************************/ +void meadows_state::meadows_sh_dac_w(int data) +{ + m_dac_data = data; + if (m_dac_enable) + m_dac->write_unsigned8(m_dac_data); + else + m_dac->write_unsigned8(0); +} |