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libsigrok/src/dmm/mm38xr.c

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/*
* This file is part of the libsigrok project.
*
* Copyright (C) 2020 Peter Skarpetis <peters@skarpetis.com>
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
/*
* Meterman 38XR protocol parser
*
* Communication parameters: Unidirectional, 9600/8n1
*
* The user guide can be downloaded from:
* https://assets.tequipment.net/assets/1/26/Documents/38XR_Manual.pdf
*
* Protocol is described in a PDF available at:
* https://www.elfadistrelec.fi/Web/Downloads/od/es/fj38XR-Serial-Output-Codes.pdf
*
* There is also a disussion about the protocol at the NI forum:
* https://forums.ni.com/t5/Digital-Multimeters-DMMs-and/Meterman-DMM/td-p/179597?profile.language=en
*
* EEVBlog discussion thread about the meter
* https://www.eevblog.com/forum/chat/meterman-38xr/
*/
/**
* @file
*
* Meterman 38XR ASCII protocol parser.
*/
#include <config.h>
#include <glib.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
#include <math.h>
#include <string.h>
#define LOG_PREFIX "mm38xr"
#define METERMAN_DIGITS_OVERLOAD 0xb0dd
#define METERMAN_DIGITS_BAD_INPUT_JACK 0xbaab
#define METERMAN_BARGRAPH_NO_SEGMENTS = 0x2a
enum mm38xr_func_code {
FUNC_CODE_UNUSED = 0x01,
FUNC_CODE_TEMPERATURE_FARENHEIGHT = 0x02,
FUNC_CODE_CURRENT_4_20_MAMPS = 0x03, /* 4-20 mA */
FUNC_CODE_DIODE_TEST = 0x04,
FUNC_CODE_INDUCTANCE_HENRIES = 0x05,
FUNC_CODE_TEMPERATURE_CELSIUS = 0x06,
FUNC_CODE_CURRENT_UAMPS = 0x07, /* uA */
FUNC_CODE_RESISTANCE_OHMS = 0x08,
FUNC_CODE_INDUCTANCE_MHENRIES = 0x09, /* mH */
FUNC_CODE_CURRENT_10_AMPS = 0x0a,
FUNC_CODE_CAPACITANCE = 0x0b,
FUNC_CODE_VOLTS_DC = 0x0c,
FUNC_CODE_LOGIC = 0x0d,
FUNC_CODE_CURRENT_MAMPS = 0x0e, /* mA */
FUNC_CODE_FREQUENCY_HZ = 0x0f, /* and duty cycle */
FUNC_CODE_VOLTS_AC = 0x10, /* and dBm */
};
enum mm38xr_meas_mode {
/* This is used to index into the digits and exponent arrays below. */
MEAS_MODE_VOLTS,
MEAS_MODE_RESISTANCE_OHMS,
MEAS_MODE_CURRENT_UAMPS, /* uA */
MEAS_MODE_CURRENT_MAMPS, /* mA */
MEAS_MODE_CURRENT_AMPS,
MEAS_MODE_CAPACITANCE,
MEAS_MODE_DIODE_TEST,
MEAS_MODE_TEMPERATURE_C,
MEAS_MODE_TEMPERATURE_F,
MEAS_MODE_FREQUENCY_HZ,
MEAS_MODE_INDUCTANCE_H,
MEAS_MODE_INDUCTANCE_MH, /* mH */
MEAS_MODE_DBM,
MEAS_MODE_DUTY_CYCLE,
MEAS_MODE_CONTINUITY,
/* For internal purposes. */
MEAS_MODE_UNDEFINED,
};
enum mm38xr_adcd_mode {
ACDC_MODE_NONE = 1000,
ACDC_MODE_DC,
ACDC_MODE_AC,
ACDC_MODE_AC_AND_DC,
};
struct meterman_info {
enum mm38xr_func_code functioncode; /* columns 0, 1 */
unsigned int reading; /* columns 2,3,4,5; LCD digits */
unsigned int bargraphsegments; /* columns 6, 7; max 40 segments, 0x2A = no bargraph */
size_t rangecode; /* column 8 */
unsigned int ampsfunction; /* column 9 */
unsigned int peakstatus; /* column 10 */
unsigned int rflag_h; /* column 11 */
unsigned int rflag_l; /* column 12 */
/* calculated values */
enum mm38xr_meas_mode meas_mode;
enum mm38xr_adcd_mode acdc;
};
static const int decimal_digits[][7] = {
[MEAS_MODE_VOLTS] = { 1, 3, 2, 1, 0, 0, 0, },
[MEAS_MODE_RESISTANCE_OHMS] = { 2, 3, 4, 2, 3, 1, 0, },
[MEAS_MODE_CURRENT_UAMPS] = { 2, 1, 0, 0, 0, 0, 0, },
[MEAS_MODE_CURRENT_MAMPS] = { 3, 2, 1, 0, 0, 0, 0, },
[MEAS_MODE_CURRENT_AMPS] = { 3, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_CAPACITANCE] = { 2, 1, 3, 2, 1, 0, 0, },
[MEAS_MODE_DIODE_TEST] = { 0, 3, 0, 0, 0, 0, 0, },
[MEAS_MODE_TEMPERATURE_C] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_TEMPERATURE_F] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_FREQUENCY_HZ] = { 2, 1, 3, 2, 1, 3, 2, },
[MEAS_MODE_INDUCTANCE_H] = { 0, 0, 0, 3, 2, 0, 0, },
[MEAS_MODE_INDUCTANCE_MH] = { 3, 2, 1, 0, 0, 0, 0, },
[MEAS_MODE_DBM] = { 2, 2, 2, 2, 2, 2, 2, },
[MEAS_MODE_DUTY_CYCLE] = { 2, 2, 2, 2, 2, 2, 2, },
[MEAS_MODE_CONTINUITY] = { 0, 0, 0, 0, 0, 1, 0, },
};
static const int units_exponents[][7] = {
[MEAS_MODE_VOLTS] = { -3, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_RESISTANCE_OHMS] = { 6, 6, 6, 3, 3, 0, 0, },
[MEAS_MODE_CURRENT_UAMPS] = { -6, -6, 0, 0, 0, 0, 0, },
[MEAS_MODE_CURRENT_MAMPS] = { -3, -3, -3, 0, 0, 0, 0, },
[MEAS_MODE_CURRENT_AMPS] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_CAPACITANCE] = { -9, -9, -6, -6, -6, 0, 0, },
[MEAS_MODE_DIODE_TEST] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_TEMPERATURE_C] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_TEMPERATURE_F] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_FREQUENCY_HZ] = { 0, 0, 3, 3, 3, 6, 6, },
[MEAS_MODE_INDUCTANCE_H] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_INDUCTANCE_MH] = { -3, -3, -3, 0, 0, 0, 0, },
[MEAS_MODE_DBM] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_DUTY_CYCLE] = { 0, 0, 0, 0, 0, 0, 0, },
[MEAS_MODE_CONTINUITY] = { 0, 0, 0, 0, 0, 0, 0, },
};
/* Assumes caller has already checked data fall within 0..9 and A..F */
static uint32_t meterman_38xr_hexnibble_to_uint(uint8_t v)
{
return (v <= '9') ? v - '0' : v - 'A' + 10;
}
static uint32_t meterman_38xr_func_code(const uint8_t *buf)
{
uint32_t v;
v = meterman_38xr_hexnibble_to_uint(buf[0]) << 4 |
meterman_38xr_hexnibble_to_uint(buf[1]);
return v;
}
static uint32_t meterman_38xr_barsegments(const uint8_t *buf)
{
uint32_t v;
v = meterman_38xr_hexnibble_to_uint(buf[6]) << 4 |
meterman_38xr_hexnibble_to_uint(buf[7]);
return v;
}
static uint32_t meterman_38xr_reading(const uint8_t *buf)
{
uint32_t v;
if (buf[2] > 'A') { /* overload */
v = meterman_38xr_hexnibble_to_uint(buf[2]) << 12 |
meterman_38xr_hexnibble_to_uint(buf[3]) << 8 |
meterman_38xr_hexnibble_to_uint(buf[4]) << 4 |
meterman_38xr_hexnibble_to_uint(buf[5]) << 0;
} else {
v = meterman_38xr_hexnibble_to_uint(buf[2]) * 1000 +
meterman_38xr_hexnibble_to_uint(buf[3]) * 100 +
meterman_38xr_hexnibble_to_uint(buf[4]) * 10 +
meterman_38xr_hexnibble_to_uint(buf[5]) * 1;
}
return v;
}
static gboolean meterman_38xr_is_negative(struct meterman_info *mi)
{
if (mi->rflag_l == 0x01)
return TRUE;
if (mi->meas_mode == MEAS_MODE_DBM && mi->rflag_l == 0x05)
return TRUE;
return FALSE;
}
static int currentACDC(struct meterman_info *mi)
{
if (mi->ampsfunction == 0x01)
return ACDC_MODE_AC;
if (mi->ampsfunction == 0x02)
return ACDC_MODE_AC_AND_DC;
return ACDC_MODE_DC;
}
static int meterman_38xr_decode(const uint8_t *buf, struct meterman_info *mi)
{
if (!meterman_38xr_packet_valid(buf))
return SR_ERR;
mi->functioncode = meterman_38xr_func_code(buf);
if (mi->functioncode < 2 || mi->functioncode > 0x10)
return SR_ERR;
mi->reading = meterman_38xr_reading(buf);
mi->bargraphsegments = meterman_38xr_barsegments(buf);
mi->rangecode = meterman_38xr_hexnibble_to_uint(buf[8]);
if (mi->rangecode > 6)
return SR_ERR;
mi->ampsfunction = meterman_38xr_hexnibble_to_uint(buf[9]);
mi->peakstatus = meterman_38xr_hexnibble_to_uint(buf[10]);
mi->rflag_h = meterman_38xr_hexnibble_to_uint(buf[11]);
mi->rflag_l = meterman_38xr_hexnibble_to_uint(buf[12]);
mi->acdc = ACDC_MODE_NONE;
switch (mi->functioncode) {
case FUNC_CODE_TEMPERATURE_FARENHEIGHT:
mi->meas_mode = MEAS_MODE_TEMPERATURE_F;
break;
case FUNC_CODE_CURRENT_4_20_MAMPS:
mi->meas_mode = MEAS_MODE_CURRENT_MAMPS;
mi->acdc = currentACDC(mi);
break;
case FUNC_CODE_DIODE_TEST:
mi->meas_mode = MEAS_MODE_DIODE_TEST;
mi->acdc = ACDC_MODE_DC;
break;
case FUNC_CODE_INDUCTANCE_HENRIES:
mi->meas_mode = MEAS_MODE_INDUCTANCE_H;
break;
case FUNC_CODE_TEMPERATURE_CELSIUS:
mi->meas_mode = MEAS_MODE_TEMPERATURE_C;
break;
case FUNC_CODE_CURRENT_UAMPS:
mi->meas_mode = MEAS_MODE_CURRENT_UAMPS;
mi->acdc = currentACDC(mi);
break;
case FUNC_CODE_RESISTANCE_OHMS:
mi->meas_mode = (mi->rflag_l == 0x08)
? MEAS_MODE_CONTINUITY
: MEAS_MODE_RESISTANCE_OHMS;
break;
case FUNC_CODE_INDUCTANCE_MHENRIES:
mi->meas_mode = MEAS_MODE_INDUCTANCE_MH;
break;
case FUNC_CODE_CURRENT_10_AMPS:
mi->meas_mode = MEAS_MODE_CURRENT_AMPS;
mi->acdc = currentACDC(mi);
break;
case FUNC_CODE_CAPACITANCE:
mi->meas_mode = MEAS_MODE_CAPACITANCE;
break;
case FUNC_CODE_VOLTS_DC:
mi->meas_mode = MEAS_MODE_VOLTS;
mi->acdc = (mi->rflag_l == 0x02)
? ACDC_MODE_AC_AND_DC : ACDC_MODE_DC;
break;
case FUNC_CODE_CURRENT_MAMPS:
mi->meas_mode = MEAS_MODE_CURRENT_MAMPS;
mi->acdc = currentACDC(mi);
break;
case FUNC_CODE_FREQUENCY_HZ:
mi->meas_mode = (mi->rflag_h == 0x0B)
? MEAS_MODE_DUTY_CYCLE
: MEAS_MODE_FREQUENCY_HZ;
break;
case FUNC_CODE_VOLTS_AC:
mi->meas_mode = (mi->rflag_l == 0x04 || mi->rflag_l == 0x05)
? MEAS_MODE_DBM : MEAS_MODE_VOLTS;
mi->acdc = ACDC_MODE_AC;
break;
default:
mi->meas_mode = MEAS_MODE_UNDEFINED;
return SR_ERR;
}
return SR_OK;
}
SR_PRIV gboolean meterman_38xr_packet_valid(const uint8_t *buf)
{
size_t i;
uint32_t fcode;
if ((buf[13] != '\r') || (buf[14] != '\n'))
return FALSE;
/* Check for all hex digits */
for (i = 0; i < 13; i++) {
if (buf[i] < '0')
return FALSE;
if (buf[i] > '9' && buf[i] < 'A')
return FALSE;
if (buf[i] > 'F')
return FALSE;
}
fcode = meterman_38xr_func_code(buf);
if (fcode < 0x01 || fcode > 0x10)
return FALSE;
return TRUE;
}
SR_PRIV int meterman_38xr_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info)
{
gboolean is_overload, is_bad_jack;
int exponent;
int digits;
struct meterman_info mi;
(void)info;
if (meterman_38xr_decode(buf, &mi) != SR_OK)
return SR_ERR;
if (mi.meas_mode != MEAS_MODE_CONTINUITY) {
is_overload = mi.reading == METERMAN_DIGITS_OVERLOAD;
is_bad_jack = mi.reading == METERMAN_DIGITS_BAD_INPUT_JACK;
if (is_overload || is_bad_jack) {
sr_spew("Over limit.");
*floatval = INFINITY; /* overload */
return SR_OK;
}
}
switch (mi.meas_mode) {
case MEAS_MODE_VOLTS:
analog->meaning->mq = SR_MQ_VOLTAGE;
analog->meaning->unit = SR_UNIT_VOLT;
break;
case MEAS_MODE_RESISTANCE_OHMS:
analog->meaning->mq = SR_MQ_RESISTANCE;
analog->meaning->unit = SR_UNIT_OHM;
break;
case MEAS_MODE_CURRENT_UAMPS:
case MEAS_MODE_CURRENT_MAMPS:
case MEAS_MODE_CURRENT_AMPS:
analog->meaning->mq = SR_MQ_CURRENT;
analog->meaning->unit = SR_UNIT_AMPERE;
break;
case MEAS_MODE_CAPACITANCE:
analog->meaning->mq = SR_MQ_CAPACITANCE;
analog->meaning->unit = SR_UNIT_FARAD;
break;
case MEAS_MODE_DIODE_TEST:
analog->meaning->mq = SR_MQ_VOLTAGE;
analog->meaning->unit = SR_UNIT_VOLT;
analog->meaning->mqflags |= SR_MQFLAG_DIODE;
break;
case MEAS_MODE_TEMPERATURE_C:
analog->meaning->mq = SR_MQ_TEMPERATURE;
analog->meaning->unit = SR_UNIT_CELSIUS;
break;
case MEAS_MODE_TEMPERATURE_F:
analog->meaning->mq = SR_MQ_TEMPERATURE;
analog->meaning->unit = SR_UNIT_FAHRENHEIT;
break;
case MEAS_MODE_FREQUENCY_HZ:
analog->meaning->mq = SR_MQ_FREQUENCY;
analog->meaning->unit = SR_UNIT_HERTZ;
break;
case MEAS_MODE_INDUCTANCE_H:
analog->meaning->mq = SR_MQ_SERIES_INDUCTANCE;
analog->meaning->unit = SR_UNIT_HENRY;
break;
case MEAS_MODE_INDUCTANCE_MH:
analog->meaning->mq = SR_MQ_SERIES_INDUCTANCE;
analog->meaning->unit = SR_UNIT_HENRY;
break;
case MEAS_MODE_DBM:
analog->meaning->mq = SR_MQ_VOLTAGE;
analog->meaning->unit = SR_UNIT_DECIBEL_MW;
analog->meaning->mqflags |= SR_MQFLAG_AC;
break;
case MEAS_MODE_DUTY_CYCLE:
analog->meaning->mq = SR_MQ_DUTY_CYCLE;
analog->meaning->unit = SR_UNIT_PERCENTAGE;
break;
case MEAS_MODE_CONTINUITY:
analog->meaning->mq = SR_MQ_CONTINUITY;
analog->meaning->unit = SR_UNIT_BOOLEAN;
*floatval = (mi.reading == METERMAN_DIGITS_OVERLOAD) ? 0.0 : 1.0;
break;
default:
return SR_ERR;
}
switch (mi.acdc) {
case ACDC_MODE_DC:
analog->meaning->mqflags |= SR_MQFLAG_DC;
break;
case ACDC_MODE_AC:
analog->meaning->mqflags |= SR_MQFLAG_AC;
break;
case ACDC_MODE_AC_AND_DC:
analog->meaning->mqflags |= SR_MQFLAG_DC | SR_MQFLAG_AC;
break;
default:
break;
}
if (mi.peakstatus == 0x02 || mi.peakstatus == 0x0a)
analog->meaning->mqflags |= SR_MQFLAG_MAX;
if (mi.peakstatus == 0x03 || mi.peakstatus == 0x0b)
analog->meaning->mqflags |= SR_MQFLAG_MIN;
if (mi.rflag_h == 0x0a || mi.peakstatus == 0x0b)
analog->meaning->mqflags |= SR_MQFLAG_AUTORANGE;
if (mi.meas_mode != MEAS_MODE_CONTINUITY) {
digits = decimal_digits[mi.meas_mode][mi.rangecode];
exponent = units_exponents[mi.meas_mode][mi.rangecode];
*floatval = mi.reading;
if (meterman_38xr_is_negative(&mi)) {
*floatval *= -1.0f;
}
*floatval *= powf(10, -digits);
*floatval *= powf(10, exponent);
}
analog->encoding->digits = 4;
analog->spec->spec_digits = 4;
return SR_OK;
}
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