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libsigrok/src/dmm/vc96.c

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/*
* This file is part of the libsigrok project.
*
* Copyright (C) 2012-2013 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2018 Matthias Schulz <matthschulz@arcor.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, see <http://www.gnu.org/licenses/>.
*/
/*
* Voltcraft 13-bytes ASCII protocol parser.
*
* Bytes 1-3 measuring mode, byte 4 '-' for negative,
* bytes 5-9 value, bytes 10-11 unit, bytes 12-13 CRLF 0d 0a.
*/
#include <config.h>
#include <string.h>
#include <strings.h>
#include <ctype.h>
#include <math.h>
#include <glib.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
#define LOG_PREFIX "vc96"
/** Parse value from buf, byte 3-8. */
static int parse_value(const uint8_t *buf, struct vc96_info *info,
float *result, int *exponent)
{
int i, is_ol, cnt, dot_pos;
char valstr[8 + 1];
(void)info;
/* Strip all spaces from bytes 3-8. */
memset(&valstr, 0, 6 + 1);
for (i = 0, cnt = 0; i < 6; i++) {
if (buf[3 + i] != ' ')
valstr[cnt++] = buf[3 + i];
}
/* Bytes 5-7: Over limit (various forms) */
is_ol = 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, ".OL")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "O.L")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "OL.")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "OL")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-.OL")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-O.L")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-OL.")) ? 1 : 0;
is_ol += (!g_ascii_strcasecmp((const char *)&valstr, "-OL")) ? 1 : 0;
if (is_ol != 0) {
sr_spew("Over limit.");
*result = INFINITY;
return SR_OK;
}
/* Bytes 3-10: Sign, value (up to 5 digits) and decimal point */
sr_atof_ascii((const char *)&valstr, result);
dot_pos = strcspn(valstr, ".");
if (dot_pos < cnt)
*exponent = -(cnt - dot_pos - 1);
else
*exponent = 0;
sr_spew("The display value is %f.", *result);
return SR_OK;
}
static void parse_flags(const char *buf, struct vc96_info *info)
{
int i, cnt;
char unit[4 + 1];
const char *u;
/* Bytes 0-1: Measurement mode AC, DC */
info->is_ac = !strncmp(buf, "AC", 2);
info->is_dc = !strncmp(buf, "DC", 2);
/* Bytes 0-2: Measurement mode DIO, OHM */
info->is_ohm = !strncmp(buf, "OHM", 3);
info->is_diode = !strncmp(buf, "DIO", 3);
info->is_hfe = !strncmp(buf, "hfe", 3);
/* Bytes 3-8: See parse_value(). */
/* Strip all spaces from bytes 9-10. */
memset(&unit, 0, 2 + 1);
for (i = 0, cnt = 0; i < 2; i++) {
if (buf[9 + i] != ' ')
unit[cnt++] = buf[9 + i];
}
sr_spew("Bytes 9..10 without spaces \"%.4s\".", unit);
/* Bytes 9-10: Unit */
u = (const char *)&unit;
if (!g_ascii_strcasecmp(u, "A"))
info->is_ampere = TRUE;
else if (!g_ascii_strcasecmp(u, "mA"))
info->is_milli = info->is_ampere = TRUE;
else if (!g_ascii_strcasecmp(u, "uA"))
info->is_micro = info->is_ampere = TRUE;
else if (!g_ascii_strcasecmp(u, "V"))
info->is_volt = TRUE;
else if (!g_ascii_strcasecmp(u, "mV"))
info->is_milli = info->is_volt = TRUE;
else if (!g_ascii_strcasecmp(u, "K"))
info->is_kilo = TRUE;
else if (!g_ascii_strcasecmp(u, "M"))
info->is_mega = TRUE;
else if (!g_ascii_strcasecmp(u, ""))
info->is_unitless = TRUE;
/* Bytes 0-2: Measurement mode, except AC/DC */
info->is_resistance = !strncmp(buf, "OHM", 3) ||
(!strncmp(buf, " ", 3) && info->is_ohm);
info->is_diode = !strncmp(buf, "DIO", 3) ||
(!strncmp(buf, " ", 3) && info->is_volt && info->is_milli);
info->is_hfe = !strncmp(buf, "hfe", 3) ||
(!strncmp(buf, " ", 3) && !info->is_ampere && !info->is_volt &&
!info->is_resistance && !info->is_diode);
/*
* Note:
* - Protocol doesn't distinguish "resistance" from "beep" mode.
*/
/* Byte 12: Always '\r' (carriage return, 0x0d, 12) */
/* Byte 13: Always '\n' (carriage return, 0x0a, 13) */
}
static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
int *exponent, const struct vc96_info *info)
{
int factor;
(void)exponent;
/* Factors */
factor = 0;
if (info->is_micro)
factor -= 6;
if (info->is_milli)
factor -= 3;
if (info->is_kilo)
factor += 3;
if (info->is_mega)
factor += 6;
*floatval *= powf(10, factor);
/* Measurement modes */
if (info->is_volt) {
analog->meaning->mq = SR_MQ_VOLTAGE;
analog->meaning->unit = SR_UNIT_VOLT;
}
if (info->is_ampere) {
analog->meaning->mq = SR_MQ_CURRENT;
analog->meaning->unit = SR_UNIT_AMPERE;
}
if (info->is_ohm) {
analog->meaning->mq = SR_MQ_RESISTANCE;
analog->meaning->unit = SR_UNIT_OHM;
}
if (info->is_diode) {
analog->meaning->mq = SR_MQ_VOLTAGE;
analog->meaning->unit = SR_UNIT_VOLT;
}
if (info->is_hfe) {
analog->meaning->mq = SR_MQ_GAIN;
analog->meaning->unit = SR_UNIT_UNITLESS;
}
/* Measurement related flags */
if (info->is_ac)
analog->meaning->mqflags |= SR_MQFLAG_AC;
if (info->is_dc)
analog->meaning->mqflags |= SR_MQFLAG_DC;
if (info->is_diode)
analog->meaning->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
}
static gboolean flags_valid(const struct vc96_info *info)
{
int count;
/* Does the packet have more than one multiplier? */
count = 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_dbg("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_diode) ? 1 : 0;
if (count > 1) {
sr_dbg("More than one measurement type detected in packet.");
return FALSE;
}
/* Both AC and DC set? */
if (info->is_ac && info->is_dc) {
sr_dbg("Both AC and DC flags detected in packet.");
return FALSE;
}
return TRUE;
}
SR_PRIV gboolean sr_vc96_packet_valid(const uint8_t *buf)
{
struct vc96_info info;
memset(&info, 0x00, sizeof(struct vc96_info));
parse_flags((const char *)buf, &info);
if (!flags_valid(&info))
return FALSE;
if ((buf[11] != '\r') || (buf[12] != '\n'))
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 vc96_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_vc96_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info)
{
int ret, exponent = 0;
struct vc96_info *info_local;
info_local = info;
/* Don't print byte 12 + 13. Those contain the CR LF. */
sr_dbg("DMM packet: \"%.11s\".", buf);
memset(info_local, 0x00, sizeof(struct vc96_info));
if ((ret = parse_value(buf, info_local, floatval, &exponent)) < 0) {
sr_dbg("Error parsing value: %d.", ret);
return ret;
}
parse_flags((const char *)buf, info_local);
handle_flags(analog, floatval, &exponent, info_local);
analog->encoding->digits = -exponent;
analog->spec->spec_digits = -exponent;
return SR_OK;
}
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