libsigrok/hardware/common/dmm/metex14.c

338 lines
9.3 KiB
C

/*
* This file is part of the libsigrok project.
*
* Copyright (C) 2012 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"
/* Message logging helpers with subsystem-specific prefix string. */
#define LOG_PREFIX "metex14: "
#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
#define sr_err(s, args...) sr_err(LOG_PREFIX s, ## args)
static int parse_value(const uint8_t *buf, float *result)
{
int i, sign, intval = 0, factor, decimal_point = 0, is_ol;
float floatval;
uint8_t digit;
/* Byte 3: Sign (' ' or '-') */
if (buf[3] == ' ') {
sign = 1;
} else if (buf[3] == '-') {
sign = -1;
} else {
sr_err("Invalid sign byte: 0x%02x.", buf[3]);
return SR_ERR;
}
/* Bytes 5-7: Over limit (various forms) */
is_ol = 0;
is_ol += (!strncmp((char *)&buf[5], ".OL", 3)) ? 1 : 0;
is_ol += (!strncmp((char *)&buf[5], "O.L", 3)) ? 1 : 0;
is_ol += (!strncmp((char *)&buf[5], "OL.", 3)) ? 1 : 0;
is_ol += (!strncmp((char *)&buf[5], " OL", 3)) ? 1 : 0;
if (is_ol != 0) {
sr_spew("Over limit.");
*result = INFINITY;
return SR_OK;
}
/* Bytes 4-8: Value (up to 4 digits) and decimal point */
factor = 1000;
for (i = 0; i < 5; i++) {
digit = buf[4 + i];
/* Convert spaces to '0', so that we can parse them. */
if (digit == ' ')
digit = '0';
if (digit == '.') {
decimal_point = i;
} else if (isdigit(digit)) {
intval += (digit - '0') * factor;
factor /= 10;
} else {
sr_err("Invalid digit byte: 0x%02x.", digit);
return SR_ERR;
}
}
floatval = (float)intval;
/* Decimal point position */
if (decimal_point == 0 || decimal_point == 4) {
/* TODO: Doesn't happen? */
} else if (decimal_point == 1) {
floatval /= 1000;
} else if (decimal_point == 2) {
floatval /= 100;
} else if (decimal_point == 3) {
floatval /= 10;
} else {
sr_err("Invalid decimal point position: %d.", decimal_point);
return SR_ERR;
}
/* Apply sign. */
floatval *= sign;
sr_spew("The display value is %f.", floatval);
*result = floatval;
return SR_OK;
}
static void parse_flags(const char *buf, struct metex14_info *info)
{
/* 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;
/* Byte 2: Always space (0x20). */
/* Bytes 3-8: See parse_value(). */
/* Bytes 9-12: Unit */
if (!strncmp(buf + 9, " A", 4))
info->is_ampere = TRUE;
else if (!strncmp(buf + 9, " mA", 4))
info->is_milli = info->is_ampere = TRUE;
else if (!strncmp(buf + 9, " uA", 4))
info->is_micro = info->is_ampere = TRUE;
else if (!strncmp(buf + 9, " V", 4))
info->is_volt = TRUE;
else if (!strncmp(buf + 9, " mV", 4))
info->is_milli = info->is_volt = TRUE;
else if (!strncmp(buf + 9, " Ohm", 4))
info->is_ohm = TRUE;
else if (!strncmp(buf + 9, "KOhm", 4))
info->is_kilo = info->is_ohm = TRUE;
else if (!strncmp(buf + 9, "MOhm", 4))
info->is_mega = info->is_ohm = TRUE;
else if (!strncmp(buf + 9, " nF", 4))
info->is_nano = info->is_farad = TRUE;
else if (!strncmp(buf + 9, " uF", 4))
info->is_micro = info->is_farad = TRUE;
else if (!strncmp(buf + 9, " KHz", 4))
info->is_kilo = info->is_hertz = TRUE;
else if (!strncmp(buf + 9, " C", 4))
info->is_celsius = TRUE;
else if (!strncmp(buf + 9, " DB", 4))
info->is_decibel = TRUE;
else if (!strncmp(buf + 9, " ", 4))
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_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;
}
static gboolean flags_valid(const struct metex14_info *info)
{
int count;
/* Does the packet have more than one multiplier? */
count = 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_err("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_err("More than one measurement type detected in packet.");
return FALSE;
}
/* Both AC and DC set? */
if (info->is_ac && info->is_dc) {
sr_err("Both AC and DC flags detected in packet.");
return FALSE;
}
return TRUE;
}
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;
}
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_err("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;
}