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c824cacd AZ |
1 | /* |
2 | * Maxim MAX1110/1111 ADC chip emulation. | |
3 | * | |
4 | * Copyright (c) 2006 Openedhand Ltd. | |
5 | * Written by Andrzej Zaborowski <balrog@zabor.org> | |
6 | * | |
7 | * This code is licensed under the GNU GPLv2. | |
8 | */ | |
9 | ||
10 | #include <vl.h> | |
11 | ||
12 | struct max111x_s { | |
13 | qemu_irq interrupt; | |
14 | uint8_t tb1, rb2, rb3; | |
15 | int cycle; | |
16 | ||
17 | int input[8]; | |
18 | int inputs, com; | |
19 | }; | |
20 | ||
21 | /* Control-byte bitfields */ | |
22 | #define CB_PD0 (1 << 0) | |
23 | #define CB_PD1 (1 << 1) | |
24 | #define CB_SGL (1 << 2) | |
25 | #define CB_UNI (1 << 3) | |
26 | #define CB_SEL0 (1 << 4) | |
27 | #define CB_SEL1 (1 << 5) | |
28 | #define CB_SEL2 (1 << 6) | |
29 | #define CB_START (1 << 7) | |
30 | ||
31 | #define CHANNEL_NUM(v, b0, b1, b2) \ | |
32 | ((((v) >> (2 + (b0))) & 4) | \ | |
33 | (((v) >> (3 + (b1))) & 2) | \ | |
34 | (((v) >> (4 + (b2))) & 1)) | |
35 | ||
36 | uint32_t max111x_read(void *opaque) | |
37 | { | |
38 | struct max111x_s *s = (struct max111x_s *) opaque; | |
39 | ||
40 | if (!s->tb1) | |
41 | return 0; | |
42 | ||
43 | switch (s->cycle ++) { | |
44 | case 1: | |
45 | return s->rb2; | |
46 | case 2: | |
47 | return s->rb3; | |
48 | } | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | /* Interpret a control-byte */ | |
54 | void max111x_write(void *opaque, uint32_t value) | |
55 | { | |
56 | struct max111x_s *s = (struct max111x_s *) opaque; | |
57 | int measure, chan; | |
58 | ||
59 | /* Ignore the value if START bit is zero */ | |
60 | if (!(value & CB_START)) | |
61 | return; | |
62 | ||
63 | s->cycle = 0; | |
64 | ||
65 | if (!(value & CB_PD1)) { | |
66 | s->tb1 = 0; | |
67 | return; | |
68 | } | |
69 | ||
70 | s->tb1 = value; | |
71 | ||
72 | if (s->inputs == 8) | |
73 | chan = CHANNEL_NUM(value, 1, 0, 2); | |
74 | else | |
75 | chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2); | |
76 | ||
77 | if (value & CB_SGL) | |
78 | measure = s->input[chan] - s->com; | |
79 | else | |
80 | measure = s->input[chan] - s->input[chan ^ 1]; | |
81 | ||
82 | if (!(value & CB_UNI)) | |
83 | measure ^= 0x80; | |
84 | ||
85 | s->rb2 = (measure >> 2) & 0x3f; | |
86 | s->rb3 = (measure << 6) & 0xc0; | |
87 | ||
88 | if (s->interrupt) | |
89 | qemu_irq_raise(s->interrupt); | |
90 | } | |
91 | ||
92 | static struct max111x_s *max111x_init(qemu_irq cb) | |
93 | { | |
94 | struct max111x_s *s; | |
95 | s = (struct max111x_s *) | |
96 | qemu_mallocz(sizeof(struct max111x_s)); | |
97 | memset(s, 0, sizeof(struct max111x_s)); | |
98 | ||
99 | s->interrupt = cb; | |
100 | ||
101 | /* TODO: add a user interface for setting these */ | |
102 | s->input[0] = 0xf0; | |
103 | s->input[1] = 0xe0; | |
104 | s->input[2] = 0xd0; | |
105 | s->input[3] = 0xc0; | |
106 | s->input[4] = 0xb0; | |
107 | s->input[5] = 0xa0; | |
108 | s->input[6] = 0x90; | |
109 | s->input[7] = 0x80; | |
110 | s->com = 0; | |
111 | return s; | |
112 | } | |
113 | ||
114 | struct max111x_s *max1110_init(qemu_irq cb) | |
115 | { | |
116 | struct max111x_s *s = max111x_init(cb); | |
117 | s->inputs = 8; | |
118 | return s; | |
119 | } | |
120 | ||
121 | struct max111x_s *max1111_init(qemu_irq cb) | |
122 | { | |
123 | struct max111x_s *s = max111x_init(cb); | |
124 | s->inputs = 4; | |
125 | return s; | |
126 | } | |
127 | ||
128 | void max111x_set_input(struct max111x_s *s, int line, uint8_t value) | |
129 | { | |
130 | if (line >= s->inputs) { | |
131 | printf("%s: There's no input %i\n", __FUNCTION__, line); | |
132 | return; | |
133 | } | |
134 | ||
135 | s->input[line] = value; | |
136 | } |