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
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
// license:BSD-3-Clause
// copyright-holders:Curt Coder
/**********************************************************************
National Semiconductor ADC0808/ADC0809 8-Bit A/D Converter emulation
The only difference between ADC0808 and ADC0809 is that the latter
chip allows twice as much adjusted error. Mitsubishi parts M58990P
and M58990P-1 are equivalent to ADC0808 and ADC0809.
**********************************************************************/
#include "emu.h"
#include "adc0808.h"
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
// device type definition
DEFINE_DEVICE_TYPE(ADC0808, adc0808_device, "adc0808", "ADC0808")
//-------------------------------------------------
// adc0808_device - constructor
//-------------------------------------------------
adc0808_device::adc0808_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, ADC0808, tag, owner, clock),
m_out_eoc_cb(*this),
m_address(0),
m_start(0),
m_eoc(0),
m_next_eoc(0), m_sar(0),
m_cycle(0),
m_bit(0),
m_cycle_timer(nullptr)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void adc0808_device::device_start()
{
// resolve callbacks
m_out_eoc_cb.resolve_safe();
m_in_vref_pos_cb.bind_relative_to(*owner());
m_in_vref_neg_cb.bind_relative_to(*owner());
m_in_in_0_cb.bind_relative_to(*owner());
m_in_in_1_cb.bind_relative_to(*owner());
m_in_in_2_cb.bind_relative_to(*owner());
m_in_in_3_cb.bind_relative_to(*owner());
m_in_in_4_cb.bind_relative_to(*owner());
m_in_in_5_cb.bind_relative_to(*owner());
m_in_in_6_cb.bind_relative_to(*owner());
m_in_in_7_cb.bind_relative_to(*owner());
// allocate timers
m_cycle_timer = timer_alloc();
m_cycle_timer->adjust(attotime::zero, 0, attotime::from_hz(clock()));
// register for state saving
save_item(NAME(m_address));
save_item(NAME(m_start));
save_item(NAME(m_eoc));
save_item(NAME(m_next_eoc));
save_item(NAME(m_sar));
save_item(NAME(m_cycle));
save_item(NAME(m_bit));
}
//-------------------------------------------------
// device_timer - handler timer events
//-------------------------------------------------
void adc0808_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
if (!m_start)
{
if (m_cycle == 7)
{
m_bit++;
if (m_bit == 8)
{
/* sample input */
double vref_pos = m_in_vref_pos_cb();
double vref_neg = m_in_vref_neg_cb();
double input = 0;
switch (m_address)
{
case 0:
input = m_in_in_0_cb();
break;
case 1:
input = m_in_in_1_cb();
break;
case 2:
input = m_in_in_2_cb();
break;
case 3:
input = m_in_in_3_cb();
break;
case 4:
input = m_in_in_4_cb();
break;
case 5:
input = m_in_in_5_cb();
break;
case 6:
input = m_in_in_6_cb();
break;
case 7:
input = m_in_in_7_cb();
break;
}
m_sar = (255 * (input - vref_neg)) / (vref_pos - vref_neg);
/* trigger end of conversion */
m_next_eoc = 1;
}
}
}
if (m_cycle == 0)
{
/* set end of conversion pin */
if (m_next_eoc != m_eoc)
{
m_out_eoc_cb(m_next_eoc);
m_eoc = m_next_eoc;
}
}
m_cycle++;
if (m_cycle == 8)
{
m_cycle = 0;
}
}
//-------------------------------------------------
// data_r - data read
//-------------------------------------------------
READ8_MEMBER( adc0808_device::data_r )
{
return m_sar;
}
//-------------------------------------------------
// ale_w - address write
//-------------------------------------------------
WRITE8_MEMBER( adc0808_device::ale_w )
{
m_address = data;
}
//-------------------------------------------------
// start_w - start conversion
//-------------------------------------------------
WRITE_LINE_MEMBER( adc0808_device::start_w )
{
if (!m_start && state) // rising edge
{
// reset registers
m_sar = 0;
m_bit = 0;
}
else if (m_start && !state) // falling edge
{
// start conversion
m_next_eoc = 0;
}
m_start = state;
}
|