--- /dev/null
+/*
+ * 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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