1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
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);
}
|