2 * This file is part of the libsigrok project.
4 * Copyright (C) 2012-2013 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
24 * Metex 14-bytes ASCII protocol parser.
27 * This should work for various multimeters which use this kind of protocol,
28 * even though there is some variation in which modes each DMM supports.
30 * It does _not_ work for all Metex DMMs, some use a quite different protocol.
39 #include <libsigrok/libsigrok.h>
40 #include "libsigrok-internal.h"
42 #define LOG_PREFIX "metex14"
44 /** Parse value from buf, byte 2-8. */
45 static int parse_value(const uint8_t *buf, struct metex14_info *info,
46 float *result, int *exponent)
48 int i, is_ol, cnt, dot_pos;
51 /* Strip all spaces from bytes 2-8. */
52 memset(&valstr, 0, 7 + 1);
53 for (i = 0, cnt = 0; i < 7; i++) {
54 if (buf[2 + i] != ' ')
55 valstr[cnt++] = buf[2 + i];
58 /* Bytes 5-7: Over limit (various forms) */
60 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, ".OL")) ? 1 : 0;
61 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "O.L")) ? 1 : 0;
62 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "OL.")) ? 1 : 0;
63 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "OL")) ? 1 : 0;
64 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-.OL")) ? 1 : 0;
65 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-O.L")) ? 1 : 0;
66 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-OL.")) ? 1 : 0;
67 is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-OL")) ? 1 : 0;
69 sr_spew("Over limit.");
75 if (!strcmp((const char *)&valstr, "READY") ||
76 !strcmp((const char *)&valstr, "FLOAT")) {
78 info->is_logic = TRUE;
79 } else if (!strcmp((const char *)&valstr, "Hi")) {
81 info->is_logic = TRUE;
82 } else if (!strcmp((const char *)&valstr, "Lo")) {
84 info->is_logic = TRUE;
89 /* Bytes 2-8: Sign, value (up to 5 digits) and decimal point */
90 sscanf((const char *)&valstr, "%f", result);
92 dot_pos = strcspn(valstr, ".");
94 *exponent = -(cnt - dot_pos - 1);
98 sr_spew("The display value is %f.", *result);
103 static void parse_flags(const char *buf, struct metex14_info *info)
109 /* Bytes 0-1: Measurement mode AC, DC */
110 info->is_ac = !strncmp(buf, "AC", 2);
111 info->is_dc = !strncmp(buf, "DC", 2);
113 /* Bytes 2-8: See parse_value(). */
115 /* Strip all spaces from bytes 9-12. */
116 memset(&unit, 0, 4 + 1);
117 for (i = 0, cnt = 0; i < 4; i++) {
118 if (buf[9 + i] != ' ')
119 unit[cnt++] = buf[9 + i];
122 /* Bytes 9-12: Unit */
123 u = (const char *)&unit;
124 if (!g_ascii_strcasecmp(u, "A"))
125 info->is_ampere = TRUE;
126 else if (!g_ascii_strcasecmp(u, "mA"))
127 info->is_milli = info->is_ampere = TRUE;
128 else if (!g_ascii_strcasecmp(u, "uA"))
129 info->is_micro = info->is_ampere = TRUE;
130 else if (!g_ascii_strcasecmp(u, "V"))
131 info->is_volt = TRUE;
132 else if (!g_ascii_strcasecmp(u, "mV"))
133 info->is_milli = info->is_volt = TRUE;
134 else if (!g_ascii_strcasecmp(u, "Ohm"))
136 else if (!g_ascii_strcasecmp(u, "KOhm"))
137 info->is_kilo = info->is_ohm = TRUE;
138 else if (!g_ascii_strcasecmp(u, "MOhm"))
139 info->is_mega = info->is_ohm = TRUE;
140 else if (!g_ascii_strcasecmp(u, "pF"))
141 info->is_pico = info->is_farad = TRUE;
142 else if (!g_ascii_strcasecmp(u, "nF"))
143 info->is_nano = info->is_farad = TRUE;
144 else if (!g_ascii_strcasecmp(u, "uF"))
145 info->is_micro = info->is_farad = TRUE;
146 else if (!g_ascii_strcasecmp(u, "KHz"))
147 info->is_kilo = info->is_hertz = TRUE;
148 else if (!g_ascii_strcasecmp(u, "C"))
149 info->is_celsius = TRUE;
150 else if (!g_ascii_strcasecmp(u, "DB"))
151 info->is_decibel = TRUE;
152 else if (!g_ascii_strcasecmp(u, ""))
153 info->is_unitless = TRUE;
155 /* Bytes 0-1: Measurement mode, except AC/DC */
156 info->is_resistance = !strncmp(buf, "OH", 2) ||
157 (!strncmp(buf, " ", 2) && info->is_ohm);
158 info->is_capacity = !strncmp(buf, "CA", 2) ||
159 (!strncmp(buf, " ", 2) && info->is_farad);
160 info->is_temperature = !strncmp(buf, "TE", 2);
161 info->is_diode = !strncmp(buf, "DI", 2) ||
162 (!strncmp(buf, " ", 2) && info->is_volt && info->is_milli);
163 info->is_frequency = !strncmp(buf, "FR", 2) ||
164 (!strncmp(buf, " ", 2) && info->is_hertz);
165 info->is_gain = !strncmp(buf, "DB", 2);
166 info->is_hfe = !strncmp(buf, "HF", 2) ||
167 (!strncmp(buf, " ", 2) && !info->is_volt && !info->is_ohm &&
168 !info->is_logic && !info->is_farad && !info->is_hertz);
171 * - Protocol doesn't distinguish "resistance" from "beep" mode.
172 * - "DB" shows the logarithmic ratio of input voltage to a
173 * pre-stored (user-changeable) value in the DMM.
176 /* Byte 13: Always '\r' (carriage return, 0x0d, 13) */
179 static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
180 int *exponent, const struct metex14_info *info)
196 *floatval *= powf(10, factor);
199 /* Measurement modes */
201 analog->meaning->mq = SR_MQ_VOLTAGE;
202 analog->meaning->unit = SR_UNIT_VOLT;
204 if (info->is_ampere) {
205 analog->meaning->mq = SR_MQ_CURRENT;
206 analog->meaning->unit = SR_UNIT_AMPERE;
209 analog->meaning->mq = SR_MQ_RESISTANCE;
210 analog->meaning->unit = SR_UNIT_OHM;
212 if (info->is_hertz) {
213 analog->meaning->mq = SR_MQ_FREQUENCY;
214 analog->meaning->unit = SR_UNIT_HERTZ;
216 if (info->is_farad) {
217 analog->meaning->mq = SR_MQ_CAPACITANCE;
218 analog->meaning->unit = SR_UNIT_FARAD;
220 if (info->is_celsius) {
221 analog->meaning->mq = SR_MQ_TEMPERATURE;
222 analog->meaning->unit = SR_UNIT_CELSIUS;
224 if (info->is_diode) {
225 analog->meaning->mq = SR_MQ_VOLTAGE;
226 analog->meaning->unit = SR_UNIT_VOLT;
229 analog->meaning->mq = SR_MQ_GAIN;
230 analog->meaning->unit = SR_UNIT_DECIBEL_VOLT;
233 analog->meaning->mq = SR_MQ_GAIN;
234 analog->meaning->unit = SR_UNIT_UNITLESS;
236 if (info->is_logic) {
237 analog->meaning->mq = SR_MQ_GAIN;
238 analog->meaning->unit = SR_UNIT_UNITLESS;
241 /* Measurement related flags */
243 analog->meaning->mqflags |= SR_MQFLAG_AC;
245 analog->meaning->mqflags |= SR_MQFLAG_DC;
247 analog->meaning->mqflags |= SR_MQFLAG_DIODE;
250 static gboolean flags_valid(const struct metex14_info *info)
254 /* Does the packet have more than one multiplier? */
256 count += (info->is_pico) ? 1 : 0;
257 count += (info->is_nano) ? 1 : 0;
258 count += (info->is_micro) ? 1 : 0;
259 count += (info->is_milli) ? 1 : 0;
260 count += (info->is_kilo) ? 1 : 0;
261 count += (info->is_mega) ? 1 : 0;
263 sr_dbg("More than one multiplier detected in packet.");
267 /* Does the packet "measure" more than one type of value? */
269 count += (info->is_ac) ? 1 : 0;
270 count += (info->is_dc) ? 1 : 0;
271 count += (info->is_resistance) ? 1 : 0;
272 count += (info->is_capacity) ? 1 : 0;
273 count += (info->is_temperature) ? 1 : 0;
274 count += (info->is_diode) ? 1 : 0;
275 count += (info->is_frequency) ? 1 : 0;
277 sr_dbg("More than one measurement type detected in packet.");
281 /* Both AC and DC set? */
282 if (info->is_ac && info->is_dc) {
283 sr_dbg("Both AC and DC flags detected in packet.");
290 #ifdef HAVE_LIBSERIALPORT
291 SR_PRIV int sr_metex14_packet_request(struct sr_serial_dev_inst *serial)
293 const uint8_t wbuf = 'D';
295 sr_spew("Requesting DMM packet.");
297 return (serial_write_nonblocking(serial, &wbuf, 1) == 1) ? SR_OK : SR_ERR;
301 SR_PRIV gboolean sr_metex14_packet_valid(const uint8_t *buf)
303 struct metex14_info info;
305 memset(&info, 0x00, sizeof(struct metex14_info));
306 parse_flags((const char *)buf, &info);
308 if (!flags_valid(&info))
318 * Parse a protocol packet.
320 * @param buf Buffer containing the protocol packet. Must not be NULL.
321 * @param floatval Pointer to a float variable. That variable will be modified
322 * in-place depending on the protocol packet. Must not be NULL.
323 * @param analog Pointer to a struct sr_datafeed_analog. The struct will be
324 * filled with data according to the protocol packet.
326 * @param info Pointer to a struct metex14_info. The struct will be filled
327 * with data according to the protocol packet. Must not be NULL.
329 * @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
330 * 'analog' variable contents are undefined and should not be used.
332 SR_PRIV int sr_metex14_parse(const uint8_t *buf, float *floatval,
333 struct sr_datafeed_analog *analog, void *info)
335 int ret, exponent = 0;
336 struct metex14_info *info_local;
338 info_local = (struct metex14_info *)info;
340 /* Don't print byte 13. That one contains the carriage return. */
341 sr_dbg("DMM packet: \"%.13s\"", buf);
343 memset(info_local, 0x00, sizeof(struct metex14_info));
345 if ((ret = parse_value(buf, info_local, floatval, &exponent)) != SR_OK) {
346 sr_dbg("Error parsing value: %d.", ret);
350 parse_flags((const char *)buf, info_local);
351 handle_flags(analog, floatval, &exponent, info_local);
353 analog->encoding->digits = -exponent;
354 analog->spec->spec_digits = -exponent;