--- /dev/null
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2014 Janne Huttunen <jahuttun@gmail.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/>.
+ */
+
+/**
+ * @file
+ *
+ * qm1578.c
+ *
+ * Digitech QM1576 serial protocol parser for libsigrok.
+ * QM1576 is a 600 count RMS DMM, with Bluetooth 4.0 support.
+ * https://www.jaycar.com.au/true-rms-digital-multimeter-with-bluetooth-connectivity/p/QM1578
+ *
+ * The protocol is described at https://www.airspayce.com/mikem/QM1578/protocol.txt
+ *
+ * You can use this decoder with libsigrok and Digitech QM1578 via ESP32 Bluetooth-Serial converter
+ * available from the author at:
+ * https://www.airspayce.com/mikem/QM1578/QM1578BluetoothClient.ino
+ * which connects to the QM1578 over Bluetooth LE, fetches the
+ * data stream and sends it on the serial port to the host, where this driver can read it
+ * with this command for example:
+ * sigrok-cli --driver digitech-qm1578:conn=/dev/ttyUSB1 --continuous
+ *
+ * See https://www.airspayce.com/mikem/QM1578//README for more data
+ *
+ * Author: mikem@airspayce.com
+ */
+
+#include <config.h>
+#include <math.h>
+#include <libsigrok/libsigrok.h>
+#include "libsigrok-internal.h"
+
+#define LOG_PREFIX "digitech-qm1578"
+
+/* Number of digits the meter supports */
+#define MAX_DIGITS 4
+
+/* Decode the multiplier prefix from buf[11] */
+static int decode_prefix(const uint8_t *buf)
+{
+ switch (buf[11]) {
+ case 0x00: return 0;
+ case 0x01: return 3;
+ case 0x02: return 6;
+ case 0x03: return -9;
+ case 0x04: return -6;
+ case 0x05: return -3; /* For amps */
+ case 0x06: return -3; /* For volts */
+ default:
+ sr_dbg("Unknown multiplier: 0x%02x.", buf[11]);
+ return -1;
+ }
+}
+
+static float decode_value(const uint8_t *buf, int *exponent)
+{
+ float val = 0.0f;
+ int i, digit;
+
+ /* On overload, digits 4 to 1 are: 0x0b 0x0a 0x00 0x0b */
+ if (buf[8] == 0x0b)
+ return INFINITY;
+
+ /* Decode the 4 digits */
+ for (i = 0; i < MAX_DIGITS; i++) {
+ digit = buf[8 - i];
+ if (digit < 0 || digit > 9)
+ continue;
+ val = 10.0 * val + digit;
+ }
+
+ *exponent = -buf[9];
+ return val;
+}
+
+SR_PRIV gboolean sr_digitech_qm1578_packet_valid(const uint8_t *buf)
+{
+ /*
+ * First 4 digits on my meter are always 0d5 0xf0 0x00 0x0a
+ * Dont know if thats the same for all meters or just mine, so ignore them
+ * and just use the presence of the trailing record separator
+ */
+ if (buf[14] != 0x0d)
+ return FALSE;
+
+ return TRUE;
+}
+
+SR_PRIV int sr_digitech_qm1578_parse(const uint8_t *buf, float *floatval,
+ struct sr_datafeed_analog *analog, void *info)
+{
+ int exponent = 0;
+ float val;
+
+ (void)info;
+
+ /* serial-dmm will dump the contents of packet by using -l 4 */
+
+ /* Defaults */
+ analog->meaning->mq = SR_MQ_GAIN;
+ analog->meaning->unit = SR_UNIT_UNITLESS;
+ analog->meaning->mqflags = 0;
+
+ /* Decode sone flags */
+ if (buf[13] & 0x10)
+ analog->meaning->mqflags |= SR_MQFLAG_AUTORANGE;
+ if (buf[13] & 0x40)
+ analog->meaning->mqflags |= SR_MQFLAG_DC;
+ if (buf[13] & 0x80)
+ analog->meaning->mqflags |= SR_MQFLAG_AC;
+ if (buf[13] & 0x20)
+ analog->meaning->mqflags |= SR_MQFLAG_RELATIVE;
+ if (buf[12] & 0x40)
+ analog->meaning->mqflags |= SR_MQFLAG_HOLD;
+ if ((buf[13] & 0x0c) == 0x0c)
+ analog->meaning->mqflags |= SR_MQFLAG_MAX;
+ if ((buf[13] & 0x0c) == 0x08)
+ analog->meaning->mqflags |= SR_MQFLAG_MIN;
+ if ((buf[13] & 0x0c) == 0x0c)
+ analog->meaning->mqflags |= SR_MQFLAG_AVG;
+
+ /* Decode the meter setting. Caution: there may be others on other meters: hFE? */
+ if (buf[4] == 0x01) {
+ analog->meaning->mq = SR_MQ_VOLTAGE;
+ analog->meaning->unit = SR_UNIT_VOLT;
+ analog->meaning->mqflags |= SR_MQFLAG_AC | SR_MQFLAG_RMS;
+ }
+ if (buf[4] == 0x02) {
+ analog->meaning->mq = SR_MQ_VOLTAGE;
+ analog->meaning->unit = SR_UNIT_VOLT;
+ analog->meaning->mqflags |= SR_MQFLAG_DC;
+ }
+ /* what is 03 ? */
+ if (buf[4] == 0x04) {
+ analog->meaning->mq = SR_MQ_RESISTANCE;
+ analog->meaning->unit = SR_UNIT_OHM;
+ }
+ if (buf[4] == 0x05) {
+ analog->meaning->mq = SR_MQ_CAPACITANCE;
+ analog->meaning->unit = SR_UNIT_FARAD;
+ }
+ if (buf[4] == 0x06) {
+ analog->meaning->mq = SR_MQ_TEMPERATURE;
+ if (buf[10] == 0x08)
+ analog->meaning->unit = SR_UNIT_CELSIUS;
+ else
+ analog->meaning->unit = SR_UNIT_FAHRENHEIT;
+ }
+ if (buf[4] == 0x07 || buf[4] == 0x08 ||buf[4] == 0x09) {
+ analog->meaning->mq = SR_MQ_CURRENT;
+ analog->meaning->unit = SR_UNIT_AMPERE;
+ analog->meaning->mqflags |= SR_MQFLAG_DC;
+ }
+ /* 0x0a ? 0x0b? */
+ if (buf[4] == 0x0c || buf[4] == 0x0d || buf[4] == 0x0e) {
+ analog->meaning->mq = SR_MQ_CURRENT;
+ analog->meaning->unit = SR_UNIT_AMPERE;
+ analog->meaning->mqflags |= SR_MQFLAG_AC | SR_MQFLAG_RMS;
+ }
+ if (buf[4] == 0x0f) {
+ analog->meaning->mq = SR_MQ_VOLTAGE;
+ analog->meaning->unit = SR_UNIT_VOLT;
+ analog->meaning->mqflags |= SR_MQFLAG_DIODE;
+ }
+ if (buf[4] == 0x10) {
+ if (buf[10] == 0x04) {
+ analog->meaning->mq = SR_MQ_FREQUENCY;
+ analog->meaning->unit = SR_UNIT_HERTZ;
+ }
+ else {
+ analog->meaning->mq = SR_MQ_DUTY_CYCLE;
+ analog->meaning->unit = SR_UNIT_PERCENTAGE;
+ }
+ }
+ if (buf[4] == 0x20) {
+ analog->meaning->mq = SR_MQ_CONTINUITY;
+ analog->meaning->unit = SR_UNIT_OHM;
+ }
+
+
+ val = decode_value(buf, &exponent);
+ exponent += decode_prefix(buf);
+ val *= powf(10, exponent);
+
+ if (buf[12] & 0x80)
+ val = -val;
+
+ *floatval = val;
+ analog->encoding->digits = -exponent;
+ analog->spec->spec_digits = -exponent;
+
+ return SR_OK;
+
+}
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