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-rw-r--r--src/mame/audio/meadows.cpp116
1 files changed, 116 insertions, 0 deletions
diff --git a/src/mame/audio/meadows.cpp b/src/mame/audio/meadows.cpp
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+++ b/src/mame/audio/meadows.cpp
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+// 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);
+}