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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 <math.h> | |
27 | #include "libsigrok.h" | |
28 | #include "libsigrok-internal.h" | |
29 | ||
30 | #define LOG_PREFIX "brymen-bm25x" | |
31 | ||
32 | #define MAX_DIGITS 4 | |
33 | ||
34 | SR_PRIV gboolean sr_brymen_bm25x_packet_valid(const uint8_t *buf) | |
35 | { | |
36 | int i; | |
37 | ||
38 | if (buf[0] != 2) | |
39 | return FALSE; | |
40 | ||
41 | for (i = 1; i < BRYMEN_BM25X_PACKET_SIZE; i++) | |
42 | if ((buf[i] >> 4) != i) | |
43 | return FALSE; | |
44 | ||
45 | return TRUE; | |
46 | } | |
47 | ||
48 | static int decode_digit(int num, const uint8_t *buf) | |
49 | { | |
50 | int val; | |
51 | ||
52 | val = (buf[3 + 2 * num] & 0xe) | ((buf[4 + 2 * num] << 4) & 0xf0); | |
53 | ||
54 | switch (val) { | |
55 | case 0xbe: return 0; | |
56 | case 0xa0: return 1; | |
57 | case 0xda: return 2; | |
58 | case 0xf8: return 3; | |
59 | case 0xe4: return 4; | |
60 | case 0x7c: return 5; | |
61 | case 0x7e: return 6; | |
62 | case 0xa8: return 7; | |
63 | case 0xfe: return 8; | |
64 | case 0xfc: return 9; | |
65 | case 0x00: return ' '; | |
66 | case 0x40: return '-'; | |
67 | case 0x16: return 'L'; | |
68 | case 0x1e: return 'C'; | |
69 | case 0x4e: return 'F'; | |
70 | case 0x5e: return 'E'; | |
71 | case 0x62: return 'n'; | |
72 | case 0x42: return 'r'; | |
73 | default: | |
74 | sr_dbg("Unknown digit: 0x%02x.", val); | |
75 | return -1; | |
76 | } | |
77 | } | |
78 | ||
79 | static int decode_point(const uint8_t *buf) | |
80 | { | |
81 | int i, p = 0; | |
82 | ||
83 | for (i = 1; i < MAX_DIGITS; i++) { | |
84 | if ((buf[11 - 2 * i] & 1) == 0) | |
85 | continue; | |
86 | if (p != 0) { | |
87 | sr_spew("Multiple decimal points found!"); | |
88 | return -1; | |
89 | } | |
90 | p = i; | |
91 | } | |
92 | ||
93 | return p; | |
94 | } | |
95 | ||
96 | static float scale_value(float val, int point, int digits) | |
97 | { | |
98 | int pos; | |
99 | ||
100 | pos = point ? point + digits - MAX_DIGITS : 0; | |
101 | ||
102 | switch (pos) { | |
103 | case 0: return val; | |
104 | case 1: return val * 1e-1; | |
105 | case 2: return val * 1e-2; | |
106 | case 3: return val * 1e-3; | |
107 | } | |
108 | ||
109 | sr_dbg("Invalid decimal point %d (%d digits).", point, digits); | |
110 | ||
111 | return NAN; | |
112 | } | |
113 | ||
114 | static float decode_prefix(const uint8_t *buf) | |
115 | { | |
116 | if (buf[11] & 2) return 1e+6; | |
117 | if (buf[11] & 1) return 1e+3; | |
118 | if (buf[13] & 1) return 1e-3; | |
119 | if (buf[13] & 2) return 1e-6; | |
120 | if (buf[12] & 1) return 1e-9; | |
121 | ||
122 | return 1.0f; | |
123 | } | |
124 | ||
125 | static float decode_value(const uint8_t *buf) | |
126 | { | |
127 | float val = 0.0f; | |
128 | int i, digit; | |
129 | ||
130 | for (i = 0; i < MAX_DIGITS; i++) { | |
131 | digit = decode_digit(i, buf); | |
132 | if (i == 3 && (digit == 'C' || digit == 'F')) | |
133 | break; | |
134 | if (digit < 0 || digit > 9) | |
135 | goto special; | |
136 | val = 10.0 * val + digit; | |
137 | } | |
138 | ||
139 | return scale_value(val, decode_point(buf), i); | |
140 | ||
141 | special: | |
142 | if (decode_digit(1, buf) == 0 && decode_digit(2, buf) == 'L') | |
143 | return INFINITY; | |
144 | ||
145 | return NAN; | |
146 | } | |
147 | ||
148 | SR_PRIV int sr_brymen_bm25x_parse(const uint8_t *buf, float *floatval, | |
149 | struct sr_datafeed_analog *analog, void *info) | |
150 | { | |
151 | float val; | |
152 | ||
153 | (void)info; | |
154 | ||
155 | analog->mq = SR_MQ_GAIN; | |
156 | analog->unit = SR_UNIT_UNITLESS; | |
157 | analog->mqflags = 0; | |
158 | ||
159 | if (buf[1] & 8) | |
160 | analog->mqflags |= SR_MQFLAG_AUTORANGE; | |
161 | if (buf[1] & 4) | |
162 | analog->mqflags |= SR_MQFLAG_DC; | |
163 | if (buf[1] & 2) | |
164 | analog->mqflags |= SR_MQFLAG_AC; | |
165 | if (buf[1] & 1) | |
166 | analog->mqflags |= SR_MQFLAG_RELATIVE; | |
167 | if (buf[11] & 8) | |
168 | analog->mqflags |= SR_MQFLAG_HOLD; | |
169 | if (buf[13] & 8) | |
170 | analog->mqflags |= SR_MQFLAG_MAX; | |
171 | if (buf[14] & 8) | |
172 | analog->mqflags |= SR_MQFLAG_MIN; | |
173 | ||
174 | if (buf[14] & 4) { | |
175 | analog->mq = SR_MQ_VOLTAGE; | |
176 | analog->unit = SR_UNIT_VOLT; | |
177 | if ((analog->mqflags & (SR_MQFLAG_DC | SR_MQFLAG_AC)) == 0) | |
178 | analog->mqflags |= SR_MQFLAG_DIODE; | |
179 | } | |
180 | if (buf[14] & 2) { | |
181 | analog->mq = SR_MQ_CURRENT; | |
182 | analog->unit = SR_UNIT_AMPERE; | |
183 | } | |
184 | if (buf[12] & 4) { | |
185 | analog->mq = SR_MQ_RESISTANCE; | |
186 | analog->unit = SR_UNIT_OHM; | |
187 | } | |
188 | if (buf[13] & 4) { | |
189 | analog->mq = SR_MQ_CAPACITANCE; | |
190 | analog->unit = SR_UNIT_FARAD; | |
191 | } | |
192 | if (buf[12] & 2) { | |
193 | analog->mq = SR_MQ_FREQUENCY; | |
194 | analog->unit = SR_UNIT_HERTZ; | |
195 | } | |
196 | ||
197 | if (decode_digit(3, buf) == 'C') { | |
198 | analog->mq = SR_MQ_TEMPERATURE; | |
199 | analog->unit = SR_UNIT_CELSIUS; | |
200 | } | |
201 | if (decode_digit(3, buf) == 'F') { | |
202 | analog->mq = SR_MQ_TEMPERATURE; | |
203 | analog->unit = SR_UNIT_FAHRENHEIT; | |
204 | } | |
205 | ||
206 | val = decode_value(buf) * decode_prefix(buf); | |
207 | ||
208 | if (buf[3] & 1) | |
209 | val = -val; | |
210 | ||
211 | *floatval = val; | |
212 | ||
213 | return SR_OK; | |
214 | } |