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1 | /* | |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2015 Martin Ling <martin-sigrok@earth.li> | |
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 2 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 | * UNI-T UT372 protocol parser. | |
22 | */ | |
23 | ||
24 | #include <config.h> | |
25 | #include <stdlib.h> | |
26 | #include <stdint.h> | |
27 | #include <math.h> | |
28 | #include <libsigrok/libsigrok.h> | |
29 | #include "libsigrok-internal.h" | |
30 | ||
31 | #define LOG_PREFIX "ut372" | |
32 | ||
33 | static const uint8_t lookup[] = { | |
34 | 0x7B, | |
35 | 0x60, | |
36 | 0x5E, | |
37 | 0x7C, | |
38 | 0x65, | |
39 | 0x3D, | |
40 | 0x3F, | |
41 | 0x70, | |
42 | 0x7F, | |
43 | 0x7D, | |
44 | }; | |
45 | ||
46 | #define DECIMAL_POINT_MASK 0x80 | |
47 | ||
48 | #define FLAGS1_HOLD_MASK (1 << 2) | |
49 | ||
50 | #define FLAGS2_RPM_MASK (1 << 0) | |
51 | #define FLAGS2_COUNT_MASK (1 << 1) | |
52 | #define FLAGS2_MAX_MASK (1 << 4) | |
53 | #define FLAGS2_MIN_MASK (1 << 5) | |
54 | #define FLAGS2_AVG_MASK (1 << 6) | |
55 | ||
56 | /* Decode a pair of characters into a byte. */ | |
57 | static uint8_t decode_pair(const uint8_t *buf) | |
58 | { | |
59 | unsigned int i; | |
60 | char hex[3]; | |
61 | ||
62 | hex[2] = '\0'; | |
63 | ||
64 | for (i = 0; i < 2; i++) { | |
65 | hex[i] = buf[i]; | |
66 | if (hex[i] > 0x39) | |
67 | hex[i] += 7; | |
68 | } | |
69 | ||
70 | return strtol(hex, NULL, 16); | |
71 | } | |
72 | ||
73 | SR_PRIV gboolean sr_ut372_packet_valid(const uint8_t *buf) | |
74 | { | |
75 | uint8_t flags2; | |
76 | ||
77 | if (!(buf[25] == '\r' && buf[26] == '\n')) | |
78 | return FALSE; | |
79 | ||
80 | flags2 = decode_pair(buf + 23); | |
81 | ||
82 | if (!(flags2 & (FLAGS2_RPM_MASK | FLAGS2_COUNT_MASK))) | |
83 | /* Device is in the setup menu - no valid data shown. */ | |
84 | return FALSE; | |
85 | ||
86 | return TRUE; | |
87 | } | |
88 | ||
89 | SR_PRIV int sr_ut372_parse(const uint8_t *buf, float *floatval, | |
90 | struct sr_datafeed_analog *analog, void *info) | |
91 | { | |
92 | unsigned int i, j, value; | |
93 | uint8_t segments, flags1, flags2; | |
94 | int exponent; | |
95 | ||
96 | (void) info; | |
97 | ||
98 | flags1 = decode_pair(buf + 21); | |
99 | flags2 = decode_pair(buf + 23); | |
100 | ||
101 | if (flags2 & FLAGS2_RPM_MASK) { | |
102 | analog->meaning->mq = SR_MQ_FREQUENCY; | |
103 | analog->meaning->unit = SR_UNIT_REVOLUTIONS_PER_MINUTE; | |
104 | } else if (flags2 & FLAGS2_COUNT_MASK) { | |
105 | analog->meaning->mq = SR_MQ_COUNT; | |
106 | analog->meaning->unit = SR_UNIT_UNITLESS; | |
107 | } | |
108 | ||
109 | if (flags1 & FLAGS1_HOLD_MASK) | |
110 | analog->meaning->mqflags |= SR_MQFLAG_HOLD; | |
111 | if (flags2 & FLAGS2_MIN_MASK) | |
112 | analog->meaning->mqflags |= SR_MQFLAG_MIN; | |
113 | if (flags2 & FLAGS2_MAX_MASK) | |
114 | analog->meaning->mqflags |= SR_MQFLAG_MAX; | |
115 | if (flags2 & FLAGS2_AVG_MASK) | |
116 | analog->meaning->mqflags |= SR_MQFLAG_AVG; | |
117 | ||
118 | value = 0; | |
119 | exponent = 0; | |
120 | ||
121 | for (i = 0; i < 5; i++) { | |
122 | segments = decode_pair(buf + 1 + (2 * i)); | |
123 | for (j = 0; j < ARRAY_SIZE(lookup); j++) { | |
124 | if (lookup[j] == (segments & ~DECIMAL_POINT_MASK)) { | |
125 | value += j * pow(10, i); | |
126 | break; | |
127 | } | |
128 | } | |
129 | if (segments & DECIMAL_POINT_MASK) | |
130 | exponent = -i; | |
131 | } | |
132 | ||
133 | *floatval = (float) value * powf(10, exponent); | |
134 | ||
135 | analog->encoding->digits = -exponent; | |
136 | analog->spec->spec_digits = -exponent; | |
137 | ||
138 | return SR_OK; | |
139 | } |