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1 | /* | |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2014 Janne Huttunen <jahuttun@gmail.com> | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | /** | |
21 | * @file | |
22 | * | |
23 | * Brymen BM25x serial protocol parser. | |
24 | */ | |
25 | ||
26 | #include <config.h> | |
27 | #include <math.h> | |
28 | #include <libsigrok/libsigrok.h> | |
29 | #include "libsigrok-internal.h" | |
30 | ||
31 | #define LOG_PREFIX "brymen-bm25x" | |
32 | ||
33 | #define MAX_DIGITS 4 | |
34 | ||
35 | SR_PRIV gboolean sr_brymen_bm25x_packet_valid(const uint8_t *buf) | |
36 | { | |
37 | int i; | |
38 | ||
39 | if (buf[0] != 2) | |
40 | return FALSE; | |
41 | ||
42 | for (i = 1; i < BRYMEN_BM25X_PACKET_SIZE; i++) | |
43 | if ((buf[i] >> 4) != i) | |
44 | return FALSE; | |
45 | ||
46 | return TRUE; | |
47 | } | |
48 | ||
49 | static int decode_digit(int num, const uint8_t *buf) | |
50 | { | |
51 | int val; | |
52 | ||
53 | val = (buf[3 + 2 * num] & 0xe) | ((buf[4 + 2 * num] << 4) & 0xf0); | |
54 | ||
55 | switch (val) { | |
56 | case 0xbe: return 0; | |
57 | case 0xa0: return 1; | |
58 | case 0xda: return 2; | |
59 | case 0xf8: return 3; | |
60 | case 0xe4: return 4; | |
61 | case 0x7c: return 5; | |
62 | case 0x7e: return 6; | |
63 | case 0xa8: return 7; | |
64 | case 0xfe: return 8; | |
65 | case 0xfc: return 9; | |
66 | case 0x00: return ' '; | |
67 | case 0x40: return '-'; | |
68 | case 0x16: return 'L'; | |
69 | case 0x1e: return 'C'; | |
70 | case 0x4e: return 'F'; | |
71 | case 0x5e: return 'E'; | |
72 | case 0x62: return 'n'; | |
73 | case 0x42: return 'r'; | |
74 | default: | |
75 | sr_dbg("Unknown digit: 0x%02x.", val); | |
76 | return -1; | |
77 | } | |
78 | } | |
79 | ||
80 | static int decode_point(const uint8_t *buf) | |
81 | { | |
82 | int i, p = 0; | |
83 | ||
84 | for (i = 1; i < MAX_DIGITS; i++) { | |
85 | if ((buf[11 - 2 * i] & 1) == 0) | |
86 | continue; | |
87 | if (p != 0) { | |
88 | sr_spew("Multiple decimal points found!"); | |
89 | return -1; | |
90 | } | |
91 | p = i; | |
92 | } | |
93 | ||
94 | return p; | |
95 | } | |
96 | ||
97 | static int decode_scale(int point, int digits) | |
98 | { | |
99 | int pos; | |
100 | ||
101 | pos = point ? point + digits - MAX_DIGITS : 0; | |
102 | ||
103 | if (pos < 0 || pos > 3) { | |
104 | sr_dbg("Invalid decimal point %d (%d digits).", point, digits); | |
105 | return 0; | |
106 | } | |
107 | return -pos; | |
108 | } | |
109 | ||
110 | static int decode_prefix(const uint8_t *buf) | |
111 | { | |
112 | if (buf[11] & 2) return 6; | |
113 | if (buf[11] & 1) return 3; | |
114 | if (buf[13] & 1) return -3; | |
115 | if (buf[13] & 2) return -6; | |
116 | if (buf[12] & 1) return -9; | |
117 | ||
118 | return 0; | |
119 | } | |
120 | ||
121 | static float decode_value(const uint8_t *buf, int *exponent) | |
122 | { | |
123 | float val = 0.0f; | |
124 | int i, digit; | |
125 | ||
126 | for (i = 0; i < MAX_DIGITS; i++) { | |
127 | digit = decode_digit(i, buf); | |
128 | if (i == 3 && (digit == 'C' || digit == 'F')) | |
129 | break; | |
130 | if (digit < 0 || digit > 9) | |
131 | goto special; | |
132 | val = 10.0 * val + digit; | |
133 | } | |
134 | ||
135 | *exponent = decode_scale(decode_point(buf), i); | |
136 | return val; | |
137 | ||
138 | special: | |
139 | if (decode_digit(1, buf) == 0 && decode_digit(2, buf) == 'L') | |
140 | return INFINITY; | |
141 | ||
142 | return NAN; | |
143 | } | |
144 | ||
145 | SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval, | |
146 | struct sr_datafeed_analog *analog, void *info) | |
147 | { | |
148 | int exponent = 0; | |
149 | float val; | |
150 | ||
151 | (void)info; | |
152 | ||
153 | analog->meaning->mq = SR_MQ_GAIN; | |
154 | analog->meaning->unit = SR_UNIT_UNITLESS; | |
155 | analog->meaning->mqflags = 0; | |
156 | ||
157 | if (buf[1] & 8) | |
158 | analog->meaning->mqflags |= SR_MQFLAG_AUTORANGE; | |
159 | if (buf[1] & 4) | |
160 | analog->meaning->mqflags |= SR_MQFLAG_DC; | |
161 | if (buf[1] & 2) | |
162 | analog->meaning->mqflags |= SR_MQFLAG_AC; | |
163 | if (buf[1] & 1) | |
164 | analog->meaning->mqflags |= SR_MQFLAG_RELATIVE; | |
165 | if (buf[11] & 8) | |
166 | analog->meaning->mqflags |= SR_MQFLAG_HOLD; | |
167 | if (buf[13] & 8) | |
168 | analog->meaning->mqflags |= SR_MQFLAG_MAX; | |
169 | if (buf[14] & 8) | |
170 | analog->meaning->mqflags |= SR_MQFLAG_MIN; | |
171 | ||
172 | if (buf[14] & 4) { | |
173 | analog->meaning->mq = SR_MQ_VOLTAGE; | |
174 | analog->meaning->unit = SR_UNIT_VOLT; | |
175 | if ((analog->meaning->mqflags & (SR_MQFLAG_DC | SR_MQFLAG_AC)) == 0) | |
176 | analog->meaning->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC; | |
177 | } | |
178 | if (buf[14] & 2) { | |
179 | analog->meaning->mq = SR_MQ_CURRENT; | |
180 | analog->meaning->unit = SR_UNIT_AMPERE; | |
181 | } | |
182 | if (buf[12] & 4) { | |
183 | analog->meaning->mq = SR_MQ_RESISTANCE; | |
184 | analog->meaning->unit = SR_UNIT_OHM; | |
185 | } | |
186 | if (buf[13] & 4) { | |
187 | analog->meaning->mq = SR_MQ_CAPACITANCE; | |
188 | analog->meaning->unit = SR_UNIT_FARAD; | |
189 | } | |
190 | if (buf[12] & 2) { | |
191 | analog->meaning->mq = SR_MQ_FREQUENCY; | |
192 | analog->meaning->unit = SR_UNIT_HERTZ; | |
193 | } | |
194 | ||
195 | if (decode_digit(3, buf) == 'C') { | |
196 | analog->meaning->mq = SR_MQ_TEMPERATURE; | |
197 | analog->meaning->unit = SR_UNIT_CELSIUS; | |
198 | } | |
199 | if (decode_digit(3, buf) == 'F') { | |
200 | analog->meaning->mq = SR_MQ_TEMPERATURE; | |
201 | analog->meaning->unit = SR_UNIT_FAHRENHEIT; | |
202 | } | |
203 | ||
204 | val = decode_value(buf, &exponent); | |
205 | exponent += decode_prefix(buf); | |
206 | val *= powf(10, exponent); | |
207 | ||
208 | if (buf[3] & 1) | |
209 | val = -val; | |
210 | ||
211 | *floatval = val; | |
212 | analog->encoding->digits = -exponent; | |
213 | analog->spec->spec_digits = -exponent; | |
214 | ||
215 | return SR_OK; | |
216 | } |