diff options
Diffstat (limited to 'src/mame/audio/meadows.c')
-rw-r--r-- | src/mame/audio/meadows.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/mame/audio/meadows.c b/src/mame/audio/meadows.c new file mode 100644 index 00000000000..c6616eb2fd6 --- /dev/null +++ b/src/mame/audio/meadows.c @@ -0,0 +1,125 @@ +/*************************************************************************** + meadows.c + Sound handler + Dead Eye, Gypsy Juggler + + J. Buchmueller, June '98 +****************************************************************************/ + +#include "driver.h" +#include "cpu/s2650/s2650.h" +#include "meadows.h" +#include "sound/samples.h" +#include "sound/dac.h" + + +UINT8 meadows_0c00 = 0; +UINT8 meadows_0c01 = 0; +UINT8 meadows_0c02 = 0; +UINT8 meadows_0c03 = 0; +static UINT8 meadows_dac = 0; +static int dac_enable; + +#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 int channel; +static int freq1 = 1000; +static int freq2 = 1000; +static INT16 waveform[2] = { -120*256, 120*256 }; + +/************************************/ +/* Sound handler start */ +/************************************/ +void meadows_sh_start(void) +{ + int vol[2]; + + vol[0]=vol[1]=255; + + sample_set_volume(0,0); + sample_start_raw(0,waveform,sizeof(waveform)/2,freq1,1); + sample_set_volume(1,0); + sample_start_raw(1,waveform,sizeof(waveform)/2,freq2,1); +} + +/************************************/ +/* Sound handler update */ +/************************************/ +void meadows_sh_update(void) +{ +static UINT8 latched_0c01 = 0; +static UINT8 latched_0c02 = 0; +static UINT8 latched_0c03 = 0; +int preset, amp; + + if (latched_0c01 != meadows_0c01 || latched_0c03 != meadows_0c03) + { + /* amplitude is a combination of the upper 4 bits of 0c01 */ + /* and bit 4 merged from S2650's flag output */ + amp = ((meadows_0c03 & ENABLE_CTR1) == 0) ? 0 : (meadows_0c01 & 0xf0) >> 1; + if( activecpu_get_reg(S2650_FO) ) + amp += 0x80; + /* calculate frequency for counter #1 */ + /* bit 0..3 of 0c01 are ctr preset */ + preset = (meadows_0c01 & 15) ^ 15; + if (preset) + freq1 = BASE_CTR1 / (preset + 1); + else amp = 0; + logerror("meadows ctr1 channel #%d preset:%3d freq:%5d amp:%d\n", channel, preset, freq1, amp); + sample_set_freq(0, freq1 * sizeof(waveform)/2); + sample_set_volume(0,amp/255.0); + } + + if (latched_0c02 != meadows_0c02 || latched_0c03 != meadows_0c03) + { + /* calculate frequency for counter #2 */ + /* 0c02 is ctr preset, 0c03 bit 0 enables division by 2 */ + amp = ((meadows_0c03 & ENABLE_CTR2) != 0) ? 0xa0 : 0; + preset = meadows_0c02 ^ 0xff; + if (preset) + { + freq2 = BASE_CTR2 / (preset + 1) / 2; + if ((meadows_0c03 & DIV2OR4_CTR2) == 0) + freq2 >>= 1; + } + else amp = 0; + logerror("meadows ctr2 channel #%d preset:%3d freq:%5d amp:%d\n", channel+1, preset, freq2, amp); + sample_set_freq(1, freq2 * sizeof(waveform)); + sample_set_volume(1,amp/255.0); + } + + if (latched_0c03 != meadows_0c03) + { + dac_enable = meadows_0c03 & ENABLE_DAC; + + if (dac_enable) + DAC_data_w(0, meadows_dac); + else + DAC_data_w(0, 0); + } + + latched_0c01 = meadows_0c01; + latched_0c02 = meadows_0c02; + latched_0c03 = meadows_0c03; +} + +/************************************/ +/* Write DAC value */ +/************************************/ +void meadows_sh_dac_w(int data) +{ + meadows_dac = data; + if (dac_enable) + DAC_data_w(0, meadows_dac); + else + DAC_data_w(0, 0); +} + + |