2 * This file is part of the sigrok project.
4 * Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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.
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.
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
22 * Metex 14-bytes ASCII protocol parser.
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.
27 * It does _not_ work for all Metex DMMs, some use a quite different protocol.
34 #include "libsigrok.h"
35 #include "libsigrok-internal.h"
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)
46 static int parse_value(const uint8_t *buf, float *result)
48 int i, sign, intval = 0, factor, decimal_point = 0, is_ol;
52 /* Byte 3: Sign (' ' or '-') */
55 } else if (buf[3] == '-') {
58 sr_err("Invalid sign byte: 0x%02x.", buf[3]);
62 /* Bytes 5-7: Over limit (various forms) */
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);
69 sr_spew("Over limit.");
74 /* Bytes 4-8: Value (up to 4 digits) and decimal point */
76 for (i = 0; i < 5; i++) {
78 /* Convert spaces to '0', so that we can parse them. */
83 } else if (isdigit(digit)) {
84 intval += (digit - '0') * factor;
87 sr_err("Invalid digit byte: 0x%02x.", digit);
92 floatval = (float)intval;
94 /* Decimal point position */
95 if (decimal_point == 0 || decimal_point == 4) {
96 /* TODO: Doesn't happen? */
97 } else if (decimal_point == 1) {
99 } else if (decimal_point == 2) {
101 } else if (decimal_point == 3) {
104 sr_err("Invalid decimal point position: %d.", decimal_point);
111 sr_spew("The display value is %f.", floatval);
118 static void parse_flags(const char *buf, struct metex14_info *info)
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);
130 if (info->is_dc || info->is_ac)
131 info->is_volt = TRUE;
133 /* Byte 2: Always space (0x20). */
135 /* Bytes 3-8: See parse_value(). */
137 /* Bytes 9-12: Unit */
138 if (!strncmp(buf + 9, " A", 4))
139 info->is_ampere = TRUE;
140 else if (!strncmp(buf + 9, " mA", 4))
141 info->is_milli = info->is_ampere = TRUE;
142 else if (!strncmp(buf + 9, " uA", 4))
143 info->is_micro = info->is_ampere = TRUE;
144 else if (!strncmp(buf + 9, " V", 4))
145 info->is_volt = TRUE;
146 else if (!strncmp(buf + 9, " mV", 4))
147 info->is_milli = info->is_volt = TRUE;
148 else if (!strncmp(buf + 9, " Ohm", 4))
150 else if (!strncmp(buf + 9, "KOhm", 4))
151 info->is_kilo = info->is_ohm = TRUE;
152 else if (!strncmp(buf + 9, "MOhm", 4))
153 info->is_mega = info->is_ohm = TRUE;
154 else if (!strncmp(buf + 9, " nF", 4))
155 info->is_nano = info->is_farad = TRUE;
156 else if (!strncmp(buf + 9, " uF", 4))
157 info->is_micro = info->is_farad = TRUE;
158 else if (!strncmp(buf + 9, " KHz", 4))
159 info->is_kilo = info->is_hertz = TRUE;
160 else if (!strncmp(buf + 9, " C", 4))
161 info->is_celsius = TRUE;
163 /* Byte 13: Always '\r' (carriage return, 0x0d, 13) */
166 static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
167 const struct metex14_info *info)
171 *floatval /= 1000000000;
173 *floatval /= 1000000;
179 *floatval *= 1000000;
181 /* Measurement modes */
183 analog->mq = SR_MQ_VOLTAGE;
184 analog->unit = SR_UNIT_VOLT;
186 if (info->is_ampere) {
187 analog->mq = SR_MQ_CURRENT;
188 analog->unit = SR_UNIT_AMPERE;
191 analog->mq = SR_MQ_RESISTANCE;
192 analog->unit = SR_UNIT_OHM;
194 if (info->is_hertz) {
195 analog->mq = SR_MQ_FREQUENCY;
196 analog->unit = SR_UNIT_HERTZ;
198 if (info->is_farad) {
199 analog->mq = SR_MQ_CAPACITANCE;
200 analog->unit = SR_UNIT_FARAD;
202 if (info->is_celsius) {
203 analog->mq = SR_MQ_TEMPERATURE;
204 analog->unit = SR_UNIT_CELSIUS;
206 if (info->is_diode) {
207 analog->mq = SR_MQ_VOLTAGE;
208 analog->unit = SR_UNIT_VOLT;
211 /* Measurement related flags */
213 analog->mqflags |= SR_MQFLAG_AC;
215 analog->mqflags |= SR_MQFLAG_DC;
218 static gboolean flags_valid(const struct metex14_info *info)
222 /* Does the packet have more than one multiplier? */
224 count += (info->is_nano) ? 1 : 0;
225 count += (info->is_micro) ? 1 : 0;
226 count += (info->is_milli) ? 1 : 0;
227 count += (info->is_kilo) ? 1 : 0;
228 count += (info->is_mega) ? 1 : 0;
230 sr_err("More than one multiplier detected in packet.");
234 /* Does the packet "measure" more than one type of value? */
236 count += (info->is_ac) ? 1 : 0;
237 count += (info->is_dc) ? 1 : 0;
238 count += (info->is_resistance) ? 1 : 0;
239 count += (info->is_capacity) ? 1 : 0;
240 count += (info->is_temperature) ? 1 : 0;
241 count += (info->is_diode) ? 1 : 0;
242 count += (info->is_frequency) ? 1 : 0;
244 sr_err("More than one measurement type detected in packet.");
248 /* Both AC and DC set? */
249 if (info->is_ac && info->is_dc) {
250 sr_err("Both AC and DC flags detected in packet.");
257 SR_PRIV gboolean sr_metex14_packet_valid(const uint8_t *buf)
259 struct metex14_info info;
261 memset(&info, 0x00, sizeof(struct metex14_info));
262 parse_flags((const char *)buf, &info);
264 if (!flags_valid(&info))
274 * Parse a protocol packet.
276 * @param buf Buffer containing the protocol packet. Must not be NULL.
277 * @param floatval Pointer to a float variable. That variable will be modified
278 * in-place depending on the protocol packet. Must not be NULL.
279 * @param analog Pointer to a struct sr_datafeed_analog. The struct will be
280 * filled with data according to the protocol packet.
282 * @param info Pointer to a struct metex14_info. The struct will be filled
283 * with data according to the protocol packet. Must not be NULL.
285 * @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
286 * 'analog' variable contents are undefined and should not be used.
288 SR_PRIV int sr_metex14_parse(const uint8_t *buf, float *floatval,
289 struct sr_datafeed_analog *analog, void *info)
292 struct metex14_info *info_local;
294 info_local = (struct metex14_info *)info;
296 /* Don't print byte 13. That one contains the carriage return. */
297 sr_dbg("DMM packet: \"%.13s\"", buf);
299 if ((ret = parse_value(buf, floatval)) != SR_OK) {
300 sr_err("Error parsing value: %d.", ret);
304 memset(info_local, 0x00, sizeof(struct metex14_info));
305 parse_flags((const char *)buf, info_local);
306 handle_flags(analog, floatval, info_local);