libsigrok/hardware/common/dmm/metex14.c

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/*
2013-04-23 20:24:30 +00:00
* This file is part of the libsigrok project.
*
* Copyright (C) 2012-2013 Uwe Hermann <uwe@hermann-uwe.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* Metex 14-bytes ASCII protocol parser.
*
* This should work for various multimeters which use this kind of protocol,
* even though there is some variation in which modes each DMM supports.
*
* It does _not_ work for all Metex DMMs, some use a quite different protocol.
*/
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <glib.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"
#define LOG_PREFIX "metex14"
static int parse_value(const uint8_t *buf, float *result)
{
int i, is_ol, cnt;
char valstr[7 + 1];
/* Strip all spaces from bytes 2-8. */
memset(&valstr, 0, 7 + 1);
for (i = 0, cnt = 0; i < 7; i++) {
if (buf[2 + i] != ' ')
valstr[cnt++] = buf[2 + i];
}
/* Bytes 5-7: Over limit (various forms) */
is_ol = 0;
is_ol += (!strcasecmp((const char *)&valstr, ".OL")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "O.L")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "OL.")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "OL")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "-.OL")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "-O.L")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "-OL.")) ? 1 : 0;
is_ol += (!strcasecmp((const char *)&valstr, "-OL")) ? 1 : 0;
if (is_ol != 0) {
sr_spew("Over limit.");
*result = INFINITY;
return SR_OK;
}
/* Bytes 2-8: Sign, value (up to 5 digits) and decimal point */
sscanf((const char *)&valstr, "%f", result);
sr_spew("The display value is %f.", *result);
return SR_OK;
}
static void parse_flags(const char *buf, struct metex14_info *info)
{
int i, cnt;
char unit[4 + 1];
const char *u;
/* Bytes 0-1: Measurement mode */
/* Note: Protocol doesn't distinguish "resistance" from "beep" mode. */
info->is_ac = !strncmp(buf, "AC", 2);
info->is_dc = !strncmp(buf, "DC", 2);
info->is_resistance = !strncmp(buf, "OH", 2);
info->is_capacity = !strncmp(buf, "CA", 2);
info->is_temperature = !strncmp(buf, "TE", 2);
info->is_diode = !strncmp(buf, "DI", 2);
info->is_frequency = !strncmp(buf, "FR", 2);
info->is_gain = !strncmp(buf, "DB", 2);
info->is_hfe = !strncmp(buf, "HF", 2);
/*
* Note: "DB" shows the logarithmic ratio of input voltage to a
* pre-stored (user-changeable) value in the DMM.
*/
if (info->is_dc || info->is_ac)
info->is_volt = TRUE;
/* Bytes 2-8: See parse_value(). */
/* Strip all spaces from bytes 9-12. */
memset(&unit, 0, 4 + 1);
for (i = 0, cnt = 0; i < 4; i++) {
if (buf[9 + i] != ' ')
unit[cnt++] = buf[9 + i];
}
/* Bytes 9-12: Unit */
u = (const char *)&unit;
if (!strcasecmp(u, "A"))
info->is_ampere = TRUE;
else if (!strcasecmp(u, "mA"))
info->is_milli = info->is_ampere = TRUE;
else if (!strcasecmp(u, "uA"))
info->is_micro = info->is_ampere = TRUE;
else if (!strcasecmp(u, "V"))
info->is_volt = TRUE;
else if (!strcasecmp(u, "mV"))
info->is_milli = info->is_volt = TRUE;
else if (!strcasecmp(u, "Ohm"))
info->is_ohm = TRUE;
else if (!strcasecmp(u, "KOhm"))
info->is_kilo = info->is_ohm = TRUE;
else if (!strcasecmp(u, "MOhm"))
info->is_mega = info->is_ohm = TRUE;
else if (!strcasecmp(u, "pF"))
info->is_pico = info->is_farad = TRUE;
else if (!strcasecmp(u, "nF"))
info->is_nano = info->is_farad = TRUE;
else if (!strcasecmp(u, "uF"))
info->is_micro = info->is_farad = TRUE;
else if (!strcasecmp(u, "KHz"))
info->is_kilo = info->is_hertz = TRUE;
else if (!strcasecmp(u, "C"))
info->is_celsius = TRUE;
else if (!strcasecmp(u, "DB"))
info->is_decibel = TRUE;
else if (!strcasecmp(u, ""))
info->is_unitless = TRUE;
/* Byte 13: Always '\r' (carriage return, 0x0d, 13) */
}
static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
const struct metex14_info *info)
{
/* Factors */
if (info->is_pico)
*floatval /= 1000000000000ULL;
if (info->is_nano)
*floatval /= 1000000000;
if (info->is_micro)
*floatval /= 1000000;
if (info->is_milli)
*floatval /= 1000;
if (info->is_kilo)
*floatval *= 1000;
if (info->is_mega)
*floatval *= 1000000;
/* Measurement modes */
if (info->is_volt) {
analog->mq = SR_MQ_VOLTAGE;
analog->unit = SR_UNIT_VOLT;
}
if (info->is_ampere) {
analog->mq = SR_MQ_CURRENT;
analog->unit = SR_UNIT_AMPERE;
}
if (info->is_ohm) {
analog->mq = SR_MQ_RESISTANCE;
analog->unit = SR_UNIT_OHM;
}
if (info->is_hertz) {
analog->mq = SR_MQ_FREQUENCY;
analog->unit = SR_UNIT_HERTZ;
}
if (info->is_farad) {
analog->mq = SR_MQ_CAPACITANCE;
analog->unit = SR_UNIT_FARAD;
}
if (info->is_celsius) {
analog->mq = SR_MQ_TEMPERATURE;
analog->unit = SR_UNIT_CELSIUS;
}
if (info->is_diode) {
analog->mq = SR_MQ_VOLTAGE;
analog->unit = SR_UNIT_VOLT;
}
if (info->is_gain) {
analog->mq = SR_MQ_GAIN;
analog->unit = SR_UNIT_DECIBEL_VOLT;
}
if (info->is_hfe) {
analog->mq = SR_MQ_GAIN;
analog->unit = SR_UNIT_UNITLESS;
}
/* Measurement related flags */
if (info->is_ac)
analog->mqflags |= SR_MQFLAG_AC;
if (info->is_dc)
analog->mqflags |= SR_MQFLAG_DC;
if (info->is_diode)
analog->mqflags |= SR_MQFLAG_DIODE;
}
static gboolean flags_valid(const struct metex14_info *info)
{
int count;
/* Does the packet have more than one multiplier? */
count = 0;
count += (info->is_pico) ? 1 : 0;
count += (info->is_nano) ? 1 : 0;
count += (info->is_micro) ? 1 : 0;
count += (info->is_milli) ? 1 : 0;
count += (info->is_kilo) ? 1 : 0;
count += (info->is_mega) ? 1 : 0;
if (count > 1) {
sr_dbg("More than one multiplier detected in packet.");
return FALSE;
}
/* Does the packet "measure" more than one type of value? */
count = 0;
count += (info->is_ac) ? 1 : 0;
count += (info->is_dc) ? 1 : 0;
count += (info->is_resistance) ? 1 : 0;
count += (info->is_capacity) ? 1 : 0;
count += (info->is_temperature) ? 1 : 0;
count += (info->is_diode) ? 1 : 0;
count += (info->is_frequency) ? 1 : 0;
if (count > 1) {
sr_dbg("More than one measurement type detected in packet.");
return FALSE;
}
/* Both AC and DC set? */
if (info->is_ac && info->is_dc) {
sr_dbg("Both AC and DC flags detected in packet.");
return FALSE;
}
return TRUE;
}
#ifdef HAVE_LIBSERIALPORT
SR_PRIV int sr_metex14_packet_request(struct sr_serial_dev_inst *serial)
{
const uint8_t wbuf = 'D';
sr_spew("Requesting DMM packet.");
return (serial_write(serial, &wbuf, 1) == 1) ? SR_OK : SR_ERR;
}
#endif
SR_PRIV gboolean sr_metex14_packet_valid(const uint8_t *buf)
{
struct metex14_info info;
memset(&info, 0x00, sizeof(struct metex14_info));
parse_flags((const char *)buf, &info);
if (!flags_valid(&info))
return FALSE;
if (buf[13] != '\r')
return FALSE;
return TRUE;
}
/**
* Parse a protocol packet.
*
* @param buf Buffer containing the protocol packet. Must not be NULL.
* @param floatval Pointer to a float variable. That variable will be modified
* in-place depending on the protocol packet. Must not be NULL.
* @param analog Pointer to a struct sr_datafeed_analog. The struct will be
* filled with data according to the protocol packet.
* Must not be NULL.
* @param info Pointer to a struct metex14_info. The struct will be filled
* with data according to the protocol packet. Must not be NULL.
*
* @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
* 'analog' variable contents are undefined and should not be used.
*/
SR_PRIV int sr_metex14_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info)
{
int ret;
struct metex14_info *info_local;
info_local = (struct metex14_info *)info;
/* Don't print byte 13. That one contains the carriage return. */
sr_dbg("DMM packet: \"%.13s\"", buf);
if ((ret = parse_value(buf, floatval)) != SR_OK) {
sr_dbg("Error parsing value: %d.", ret);
return ret;
}
memset(info_local, 0x00, sizeof(struct metex14_info));
parse_flags((const char *)buf, info_local);
handle_flags(analog, floatval, info_local);
return SR_OK;
}