338 lines
9.3 KiB
C
338 lines
9.3 KiB
C
/*
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* This file is part of the libsigrok project.
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*
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* Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/*
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* Metex 14-bytes ASCII protocol parser.
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*
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* This should work for various multimeters which use this kind of protocol,
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* even though there is some variation in which modes each DMM supports.
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*
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* It does _not_ work for all Metex DMMs, some use a quite different protocol.
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*/
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#include <string.h>
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#include <ctype.h>
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#include <math.h>
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#include <glib.h>
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#include "libsigrok.h"
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#include "libsigrok-internal.h"
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/* Message logging helpers with subsystem-specific prefix string. */
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#define LOG_PREFIX "metex14: "
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#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
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#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
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#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
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#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
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#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
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#define sr_err(s, args...) sr_err(LOG_PREFIX s, ## args)
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static int parse_value(const uint8_t *buf, float *result)
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{
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int i, sign, intval = 0, factor, decimal_point = 0, is_ol;
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float floatval;
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uint8_t digit;
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/* Byte 3: Sign (' ' or '-') */
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if (buf[3] == ' ') {
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sign = 1;
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} else if (buf[3] == '-') {
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sign = -1;
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} else {
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sr_err("Invalid sign byte: 0x%02x.", buf[3]);
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return SR_ERR;
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}
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/* Bytes 5-7: Over limit (various forms) */
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is_ol = 0;
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is_ol += (!strncmp((char *)&buf[5], ".OL", 3)) ? 1 : 0;
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is_ol += (!strncmp((char *)&buf[5], "O.L", 3)) ? 1 : 0;
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is_ol += (!strncmp((char *)&buf[5], "OL.", 3)) ? 1 : 0;
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is_ol += (!strncmp((char *)&buf[5], " OL", 3)) ? 1 : 0;
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if (is_ol != 0) {
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sr_spew("Over limit.");
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*result = INFINITY;
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return SR_OK;
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}
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/* Bytes 4-8: Value (up to 4 digits) and decimal point */
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factor = 1000;
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for (i = 0; i < 5; i++) {
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digit = buf[4 + i];
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/* Convert spaces to '0', so that we can parse them. */
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if (digit == ' ')
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digit = '0';
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if (digit == '.') {
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decimal_point = i;
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} else if (isdigit(digit)) {
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intval += (digit - '0') * factor;
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factor /= 10;
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} else {
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sr_err("Invalid digit byte: 0x%02x.", digit);
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return SR_ERR;
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}
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}
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floatval = (float)intval;
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/* Decimal point position */
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if (decimal_point == 0 || decimal_point == 4) {
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/* TODO: Doesn't happen? */
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} else if (decimal_point == 1) {
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floatval /= 1000;
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} else if (decimal_point == 2) {
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floatval /= 100;
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} else if (decimal_point == 3) {
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floatval /= 10;
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} else {
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sr_err("Invalid decimal point position: %d.", decimal_point);
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return SR_ERR;
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}
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/* Apply sign. */
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floatval *= sign;
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sr_spew("The display value is %f.", floatval);
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*result = floatval;
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return SR_OK;
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}
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static void parse_flags(const char *buf, struct metex14_info *info)
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{
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/* Bytes 0-1: Measurement mode */
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/* Note: Protocol doesn't distinguish "resistance" from "beep" mode. */
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info->is_ac = !strncmp(buf, "AC", 2);
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info->is_dc = !strncmp(buf, "DC", 2);
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info->is_resistance = !strncmp(buf, "OH", 2);
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info->is_capacity = !strncmp(buf, "CA", 2);
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info->is_temperature = !strncmp(buf, "TE", 2);
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info->is_diode = !strncmp(buf, "DI", 2);
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info->is_frequency = !strncmp(buf, "FR", 2);
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info->is_gain = !strncmp(buf, "DB", 2);
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info->is_hfe = !strncmp(buf, "HF", 2);
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/*
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* Note: "DB" shows the logarithmic ratio of input voltage to a
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* pre-stored (user-changeable) value in the DMM.
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*/
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if (info->is_dc || info->is_ac)
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info->is_volt = TRUE;
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/* Byte 2: Always space (0x20). */
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/* Bytes 3-8: See parse_value(). */
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/* Bytes 9-12: Unit */
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if (!strncmp(buf + 9, " A", 4))
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info->is_ampere = TRUE;
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else if (!strncmp(buf + 9, " mA", 4))
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info->is_milli = info->is_ampere = TRUE;
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else if (!strncmp(buf + 9, " uA", 4))
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info->is_micro = info->is_ampere = TRUE;
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else if (!strncmp(buf + 9, " V", 4))
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info->is_volt = TRUE;
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else if (!strncmp(buf + 9, " mV", 4))
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info->is_milli = info->is_volt = TRUE;
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else if (!strncmp(buf + 9, " Ohm", 4))
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info->is_ohm = TRUE;
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else if (!strncmp(buf + 9, "KOhm", 4))
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info->is_kilo = info->is_ohm = TRUE;
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else if (!strncmp(buf + 9, "MOhm", 4))
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info->is_mega = info->is_ohm = TRUE;
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else if (!strncmp(buf + 9, " nF", 4))
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info->is_nano = info->is_farad = TRUE;
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else if (!strncmp(buf + 9, " uF", 4))
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info->is_micro = info->is_farad = TRUE;
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else if (!strncmp(buf + 9, " KHz", 4))
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info->is_kilo = info->is_hertz = TRUE;
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else if (!strncmp(buf + 9, " C", 4))
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info->is_celsius = TRUE;
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else if (!strncmp(buf + 9, " DB", 4))
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info->is_decibel = TRUE;
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else if (!strncmp(buf + 9, " ", 4))
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info->is_unitless = TRUE;
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/* Byte 13: Always '\r' (carriage return, 0x0d, 13) */
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}
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static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
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const struct metex14_info *info)
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{
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/* Factors */
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if (info->is_nano)
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*floatval /= 1000000000;
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if (info->is_micro)
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*floatval /= 1000000;
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if (info->is_milli)
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*floatval /= 1000;
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if (info->is_kilo)
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*floatval *= 1000;
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if (info->is_mega)
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*floatval *= 1000000;
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/* Measurement modes */
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if (info->is_volt) {
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analog->mq = SR_MQ_VOLTAGE;
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analog->unit = SR_UNIT_VOLT;
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}
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if (info->is_ampere) {
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analog->mq = SR_MQ_CURRENT;
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analog->unit = SR_UNIT_AMPERE;
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}
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if (info->is_ohm) {
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analog->mq = SR_MQ_RESISTANCE;
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analog->unit = SR_UNIT_OHM;
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}
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if (info->is_hertz) {
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analog->mq = SR_MQ_FREQUENCY;
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analog->unit = SR_UNIT_HERTZ;
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}
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if (info->is_farad) {
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analog->mq = SR_MQ_CAPACITANCE;
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analog->unit = SR_UNIT_FARAD;
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}
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if (info->is_celsius) {
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analog->mq = SR_MQ_TEMPERATURE;
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analog->unit = SR_UNIT_CELSIUS;
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}
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if (info->is_diode) {
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analog->mq = SR_MQ_VOLTAGE;
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analog->unit = SR_UNIT_VOLT;
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}
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if (info->is_gain) {
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analog->mq = SR_MQ_GAIN;
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analog->unit = SR_UNIT_DECIBEL_VOLT;
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}
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if (info->is_hfe) {
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analog->mq = SR_MQ_GAIN;
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analog->unit = SR_UNIT_UNITLESS;
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}
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/* Measurement related flags */
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if (info->is_ac)
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analog->mqflags |= SR_MQFLAG_AC;
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if (info->is_dc)
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analog->mqflags |= SR_MQFLAG_DC;
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}
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static gboolean flags_valid(const struct metex14_info *info)
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{
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int count;
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/* Does the packet have more than one multiplier? */
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count = 0;
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count += (info->is_nano) ? 1 : 0;
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count += (info->is_micro) ? 1 : 0;
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count += (info->is_milli) ? 1 : 0;
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count += (info->is_kilo) ? 1 : 0;
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count += (info->is_mega) ? 1 : 0;
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if (count > 1) {
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sr_err("More than one multiplier detected in packet.");
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return FALSE;
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}
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/* Does the packet "measure" more than one type of value? */
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count = 0;
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count += (info->is_ac) ? 1 : 0;
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count += (info->is_dc) ? 1 : 0;
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count += (info->is_resistance) ? 1 : 0;
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count += (info->is_capacity) ? 1 : 0;
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count += (info->is_temperature) ? 1 : 0;
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count += (info->is_diode) ? 1 : 0;
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count += (info->is_frequency) ? 1 : 0;
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if (count > 1) {
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sr_err("More than one measurement type detected in packet.");
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return FALSE;
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}
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/* Both AC and DC set? */
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if (info->is_ac && info->is_dc) {
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sr_err("Both AC and DC flags detected in packet.");
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return FALSE;
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}
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return TRUE;
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}
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SR_PRIV int sr_metex14_packet_request(struct sr_serial_dev_inst *serial)
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{
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const uint8_t wbuf = 'D';
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sr_spew("Requesting DMM packet.");
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return (serial_write(serial, &wbuf, 1) == 1) ? SR_OK : SR_ERR;
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}
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SR_PRIV gboolean sr_metex14_packet_valid(const uint8_t *buf)
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{
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struct metex14_info info;
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memset(&info, 0x00, sizeof(struct metex14_info));
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parse_flags((const char *)buf, &info);
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if (!flags_valid(&info))
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return FALSE;
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if (buf[13] != '\r')
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return FALSE;
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return TRUE;
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}
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/**
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* Parse a protocol packet.
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*
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* @param buf Buffer containing the protocol packet. Must not be NULL.
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* @param floatval Pointer to a float variable. That variable will be modified
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* in-place depending on the protocol packet. Must not be NULL.
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* @param analog Pointer to a struct sr_datafeed_analog. The struct will be
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* filled with data according to the protocol packet.
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* Must not be NULL.
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* @param info Pointer to a struct metex14_info. The struct will be filled
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* with data according to the protocol packet. Must not be NULL.
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*
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* @return SR_OK upon success, SR_ERR upon failure. Upon errors, the
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* 'analog' variable contents are undefined and should not be used.
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*/
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SR_PRIV int sr_metex14_parse(const uint8_t *buf, float *floatval,
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struct sr_datafeed_analog *analog, void *info)
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{
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int ret;
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struct metex14_info *info_local;
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info_local = (struct metex14_info *)info;
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/* Don't print byte 13. That one contains the carriage return. */
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sr_dbg("DMM packet: \"%.13s\"", buf);
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if ((ret = parse_value(buf, floatval)) != SR_OK) {
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sr_err("Error parsing value: %d.", ret);
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return ret;
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}
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memset(info_local, 0x00, sizeof(struct metex14_info));
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parse_flags((const char *)buf, info_local);
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handle_flags(analog, floatval, info_local);
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return SR_OK;
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}
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