]> sigrok.org Git - libsigrok.git/blame - hardware/common/dmm/metex14.c
metex14: Fix parsing of spaces.
[libsigrok.git] / hardware / common / dmm / metex14.c
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1/*
2 * This file is part of the sigrok project.
3 *
4 * Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/*
22 * Metex 14-bytes ASCII protocol parser.
23 *
24 * This should work for various multimeters which use this kind of protocol,
25 * even though there is some variation in which modes each DMM supports.
26 *
27 * It does _not_ work for all Metex DMMs, some use a quite different protocol.
28 */
29
30#include <string.h>
31#include <ctype.h>
32#include <math.h>
33#include <glib.h>
34#include "libsigrok.h"
35#include "libsigrok-internal.h"
36
37/* Message logging helpers with driver-specific prefix string. */
38#define DRIVER_LOG_DOMAIN "metex14: "
39#define sr_log(l, s, args...) sr_log(l, DRIVER_LOG_DOMAIN s, ## args)
40#define sr_spew(s, args...) sr_spew(DRIVER_LOG_DOMAIN s, ## args)
41#define sr_dbg(s, args...) sr_dbg(DRIVER_LOG_DOMAIN s, ## args)
42#define sr_info(s, args...) sr_info(DRIVER_LOG_DOMAIN s, ## args)
43#define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args)
44#define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args)
45
46static int parse_value(const uint8_t *buf, float *result)
47{
48 int i, sign, intval = 0, factor, decimal_point = 0, is_ol;
49 float floatval;
50 uint8_t digit;
51
52 /* Byte 3: Sign (' ' or '-') */
53 if (buf[3] == ' ') {
54 sign = 1;
55 } else if (buf[3] == '-') {
56 sign = -1;
57 } else {
58 sr_err("Invalid sign byte: 0x%02x.", buf[3]);
59 return SR_ERR;
60 }
61
62 /* Bytes 5-7: Over limit (various forms) */
63 is_ol = 0;
64 is_ol += !strncmp((char *)&buf[5], ".OL", 3);
65 is_ol += !strncmp((char *)&buf[5], "O.L", 3);
66 is_ol += !strncmp((char *)&buf[5], "OL.", 3);
67 is_ol += !strncmp((char *)&buf[5], " OL", 3);
68 if (is_ol != 0) {
69 sr_spew("Over limit.");
70 *result = INFINITY;
71 return SR_OK;
72 }
73
74 /* Bytes 4-8: Value (up to 4 digits) and decimal point */
75 factor = 1000;
76 for (i = 0; i < 5; i++) {
77 digit = buf[4 + i];
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78 /* Convert spaces to '0', so that we can parse them. */
79 if (digit == ' ')
80 digit = '0';
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81 if (digit == '.') {
82 decimal_point = i;
83 } else if (isdigit(digit)) {
84 intval += (digit - '0') * factor;
85 factor /= 10;
86 } else {
87 sr_err("Invalid digit byte: 0x%02x.", digit);
88 return SR_ERR;
89 }
90 }
91
92 floatval = (float)intval;
93
94 /* Decimal point position */
95 if (decimal_point == 0 || decimal_point == 4) {
96 /* TODO: Doesn't happen? */
97 } else if (decimal_point == 1) {
98 floatval /= 1000;
99 } else if (decimal_point == 2) {
100 floatval /= 100;
101 } else if (decimal_point == 3) {
102 floatval /= 10;
103 } else {
104 sr_err("Invalid decimal point position: %d.", decimal_point);
105 return SR_ERR;
106 }
107
108 /* Apply sign. */
109 floatval *= sign;
110
111 sr_spew("The display value is %f.", floatval);
112
113 *result = floatval;
114
115 return SR_OK;
116}
117
118static void parse_flags(const char *buf, struct metex14_info *info)
119{
120 /* Bytes 0-1: Measurement mode */
121 /* Note: Protocol doesn't distinguish "resistance" from "beep" mode. */
122 info->is_ac = !strncmp(buf, "AC", 2);
123 info->is_dc = !strncmp(buf, "DC", 2);
124 info->is_resistance = !strncmp(buf, "OH", 2);
125 info->is_capacity = !strncmp(buf, "CA", 2);
126 info->is_temperature = !strncmp(buf, "TE", 2);
127 info->is_diode = !strncmp(buf, "DI", 2);
128 info->is_frequency = !strncmp(buf, "FR", 2);
129
130 if (info->is_dc || info->is_ac)
131 info->is_volt = TRUE;
132
133 /* Byte 2: Always space (0x20). */
134
135 /* Bytes 3-8: See parse_value(). */
136
137 /* Bytes 9-12: Unit */
138 if (!strcmp(buf + 9, " A"))
139 info->is_ampere = TRUE;
140 else if (!strcmp(buf + 9, " mA"))
141 info->is_milli = info->is_ampere = TRUE;
142 else if (!strcmp(buf + 9, " V"))
143 info->is_volt = TRUE;
144 else if (!strcmp(buf + 9, " mV"))
145 info->is_milli = info->is_volt = TRUE;
146 else if (!strcmp(buf + 9, " Ohm"))
147 info->is_ohm = TRUE;
148 else if (!strcmp(buf + 9, "KOhm"))
149 info->is_kilo = info->is_ohm = TRUE;
150 else if (!strcmp(buf + 9, "MOhm"))
151 info->is_mega = info->is_ohm = TRUE;
152 else if (!strcmp(buf + 9, " nF"))
153 info->is_nano = info->is_farad = TRUE;
154 else if (!strcmp(buf + 9, " uF"))
155 info->is_micro = info->is_farad = TRUE;
156 else if (!strcmp(buf + 9, " KHz"))
157 info->is_kilo = info->is_hertz = TRUE;
158 else if (!strcmp(buf + 9, " C"))
159 info->is_celsius = TRUE;
160
161 /* Byte 13: Always '\r' (carriage return, 0x0d, 13) */
162}
163
164static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
165 const struct metex14_info *info)
166{
167 /* Factors */
168 if (info->is_nano)
169 *floatval /= 1000000000;
170 if (info->is_micro)
171 *floatval /= 1000000;
172 if (info->is_milli)
173 *floatval /= 1000;
174 if (info->is_kilo)
175 *floatval *= 1000;
176 if (info->is_mega)
177 *floatval *= 1000000;
178
179 /* Measurement modes */
180 if (info->is_volt) {
181 analog->mq = SR_MQ_VOLTAGE;
182 analog->unit = SR_UNIT_VOLT;
183 }
184 if (info->is_ampere) {
185 analog->mq = SR_MQ_CURRENT;
186 analog->unit = SR_UNIT_AMPERE;
187 }
188 if (info->is_ohm) {
189 analog->mq = SR_MQ_RESISTANCE;
190 analog->unit = SR_UNIT_OHM;
191 }
192 if (info->is_hertz) {
193 analog->mq = SR_MQ_FREQUENCY;
194 analog->unit = SR_UNIT_HERTZ;
195 }
196 if (info->is_farad) {
197 analog->mq = SR_MQ_CAPACITANCE;
198 analog->unit = SR_UNIT_FARAD;
199 }
200 if (info->is_celsius) {
201 analog->mq = SR_MQ_TEMPERATURE;
202 analog->unit = SR_UNIT_CELSIUS;
203 }
204 if (info->is_diode) {
205 analog->mq = SR_MQ_VOLTAGE;
206 analog->unit = SR_UNIT_VOLT;
207 }
208
209 /* Measurement related flags */
210 if (info->is_ac)
211 analog->mqflags |= SR_MQFLAG_AC;
212 if (info->is_dc)
213 analog->mqflags |= SR_MQFLAG_DC;
214}
215
216static gboolean flags_valid(const struct metex14_info *info)
217{
218 int count;
219
220 /* Does the packet have more than one multiplier? */
221 count = 0;
222 count += (info->is_nano) ? 1 : 0;
223 count += (info->is_micro) ? 1 : 0;
224 count += (info->is_milli) ? 1 : 0;
225 count += (info->is_kilo) ? 1 : 0;
226 count += (info->is_mega) ? 1 : 0;
227 if (count > 1) {
228 sr_err("More than one multiplier detected in packet.");
229 return FALSE;
230 }
231
232 /* Does the packet "measure" more than one type of value? */
233 count = 0;
234 count += (info->is_ac) ? 1 : 0;
235 count += (info->is_dc) ? 1 : 0;
236 count += (info->is_resistance) ? 1 : 0;
237 count += (info->is_capacity) ? 1 : 0;
238 count += (info->is_temperature) ? 1 : 0;
239 count += (info->is_diode) ? 1 : 0;
240 count += (info->is_frequency) ? 1 : 0;
241 if (count > 1) {
242 sr_err("More than one measurement type detected in packet.");
243 return FALSE;
244 }
245
246 /* Both AC and DC set? */
247 if (info->is_ac && info->is_dc) {
248 sr_err("Both AC and DC flags detected in packet.");
249 return FALSE;
250 }
251
252 return TRUE;
253}
254
255SR_PRIV gboolean sr_metex14_packet_valid(const uint8_t *buf)
256{
257 struct metex14_info info;
258
259 memset(&info, 0x00, sizeof(struct metex14_info));
260 parse_flags((const char *)buf, &info);
261
262 if (!flags_valid(&info))
263 return FALSE;
264
265 if (buf[13] != '\r')
266 return FALSE;
267
268 return TRUE;
269}
270
271/**
272 * Parse a protocol packet.
273 *
1fbab466 274 * @param buf Buffer containing the protocol packet. Must not be NULL.
ac913e5c 275 * @param floatval Pointer to a float variable. That variable will be modified
1fbab466 276 * in-place depending on the protocol packet. Must not be NULL.
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277 * @param analog Pointer to a struct sr_datafeed_analog. The struct will be
278 * filled with data according to the protocol packet.
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279 * Must not be NULL.
280 * @param info Pointer to a struct metex14_info. The struct will be filled
281 * with data according to the protocol packet. Must not be NULL.
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282 *
283 * @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
284 * 'analog' variable contents are undefined and should not be used.
285 */
286SR_PRIV int sr_metex14_parse(const uint8_t *buf, float *floatval,
1fbab466 287 struct sr_datafeed_analog *analog, void *info)
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288{
289 int ret;
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290 struct metex14_info *info_local;
291
292 info_local = (struct metex14_info *)info;
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293
294 if ((ret = parse_value(buf, floatval)) != SR_OK) {
295 sr_err("Error parsing value: %d.", ret);
296 return ret;
297 }
298
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299 memset(info_local, 0x00, sizeof(struct metex14_info));
300 parse_flags((const char *)buf, info_local);
301 handle_flags(analog, floatval, info_local);
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302
303 return SR_OK;
304}