[libsigrok.git] / src / dmm / rs9lcd.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@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/>.
 */

/*
 * RadioShack 22-812 protocol parser.
 *
 * This protocol is currently encountered on the RadioShack 22-812 DMM.
 * It is a 9-byte packet representing a 1:1 mapping of the LCD segments, hence
 * the name rs9lcd.
 *
 * The chip is a bare die covered by a plastic blob. It is unclear if this chip
 * and protocol is used on any other device.
 */

#include <config.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <glib.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"

#define LOG_PREFIX "rs9lcd"

/* Byte 1 of the packet, and the modes it represents */
#define IND1_HZ		(1 << 7)
#define IND1_OHM	(1 << 6)
#define IND1_KILO	(1 << 5)
#define IND1_MEGA	(1 << 4)
#define IND1_FARAD	(1 << 3)
#define IND1_AMP	(1 << 2)
#define IND1_VOLT	(1 << 1)
#define IND1_MILI	(1 << 0)
/* Byte 2 of the packet, and the modes it represents */
#define IND2_MICRO	(1 << 7)
#define IND2_NANO	(1 << 6)
#define IND2_DBM	(1 << 5)
#define IND2_SEC	(1 << 4)
#define IND2_DUTY	(1 << 3)
#define IND2_HFE	(1 << 2)
#define IND2_REL	(1 << 1)
#define IND2_MIN	(1 << 0)
/* Byte 7 of the packet, and the modes it represents */
#define INFO_BEEP	(1 << 7)
#define INFO_DIODE	(1 << 6)
#define INFO_BAT	(1 << 5)
#define INFO_HOLD	(1 << 4)
#define INFO_NEG	(1 << 3)
#define INFO_AC		(1 << 2)
#define INFO_RS232	(1 << 1)
#define INFO_AUTO	(1 << 0)
/* Instead of a decimal point, digit 4 carries the MAX flag */
#define DIG4_MAX	(1 << 3)
/* Mask to remove the decimal point from a digit */
#define DP_MASK		(1 << 3)

/* What the LCD values represent */
#define LCD_0		0xd7
#define LCD_1		0x50
#define LCD_2		0xb5
#define LCD_3		0xf1
#define LCD_4		0x72
#define LCD_5		0xe3
#define LCD_6		0xe7
#define LCD_7		0x51
#define LCD_8		0xf7
#define LCD_9		0xf3

#define LCD_C		0x87
#define LCD_E
#define LCD_F
#define LCD_h		0x66
#define LCD_H		0x76
#define LCD_I
#define LCD_n
#define LCD_P		0x37
#define LCD_r

enum {
	MODE_DC_V	= 0,
	MODE_AC_V	= 1,
	MODE_DC_UA	= 2,
	MODE_DC_MA	= 3,
	MODE_DC_A 	= 4,
	MODE_AC_UA	= 5,
	MODE_AC_MA	= 6,
	MODE_AC_A	= 7,
	MODE_OHM	= 8,
	MODE_FARAD	= 9,
	MODE_HZ		= 10,
	MODE_VOLT_HZ	= 11,	/* Dial set to V, Hz selected by Hz button */
	MODE_AMP_HZ	= 12,	/* Dial set to A, Hz selected by Hz button */
	MODE_DUTY	= 13,
	MODE_VOLT_DUTY	= 14,	/* Dial set to V, duty cycle selected */
	MODE_AMP_DUTY	= 15,	/* Dial set to A, duty cycle selected */
	MODE_WIDTH	= 16,
	MODE_VOLT_WIDTH	= 17,	/* Dial set to V, pulse width selected */
	MODE_AMP_WIDTH	= 18,	/* Dial set to A, pulse width selected */
	MODE_DIODE	= 19,
	MODE_CONT	= 20,
	MODE_HFE	= 21,
	MODE_LOGIC	= 22,
	MODE_DBM	= 23,
	/* MODE_EF	= 24, */ /* Not encountered on any DMM */
	MODE_TEMP	= 25,
	MODE_INVALID	= 26,
};

enum {
	READ_ALL,
	READ_TEMP,
};

struct rs9lcd_packet {
	uint8_t mode;
	uint8_t indicatrix1;
	uint8_t indicatrix2;
	uint8_t digit4;
	uint8_t digit3;
	uint8_t digit2;
	uint8_t digit1;
	uint8_t info;
	uint8_t checksum;
};

static gboolean checksum_valid(const struct rs9lcd_packet *rs_packet)
{
	uint8_t *raw;
	uint8_t sum = 0;
	int i;

	raw = (void *)rs_packet;

	for (i = 0; i < RS9LCD_PACKET_SIZE - 1; i++)
		sum += raw[i];

	/* This is just a funky constant added to the checksum. */
	sum += 57;
	sum -= rs_packet->checksum;
	return (sum == 0);
}

static gboolean selection_good(const struct rs9lcd_packet *rs_packet)
{
	int count;

	/* Does the packet have more than one multiplier? */
	count = 0;
	count += (rs_packet->indicatrix1 & IND1_KILO)  ? 1 : 0;
	count += (rs_packet->indicatrix1 & IND1_MEGA)  ? 1 : 0;
	count += (rs_packet->indicatrix1 & IND1_MILI)  ? 1 : 0;
	count += (rs_packet->indicatrix2 & IND2_MICRO) ? 1 : 0;
	count += (rs_packet->indicatrix2 & IND2_NANO)  ? 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 += (rs_packet->indicatrix1 & IND1_HZ)    ? 1 : 0;
	count += (rs_packet->indicatrix1 & IND1_OHM)   ? 1 : 0;
	count += (rs_packet->indicatrix1 & IND1_FARAD) ? 1 : 0;
	count += (rs_packet->indicatrix1 & IND1_AMP)   ? 1 : 0;
	count += (rs_packet->indicatrix1 & IND1_VOLT)  ? 1 : 0;
	count += (rs_packet->indicatrix2 & IND2_DBM)   ? 1 : 0;
	count += (rs_packet->indicatrix2 & IND2_SEC)   ? 1 : 0;
	count += (rs_packet->indicatrix2 & IND2_DUTY)  ? 1 : 0;
	count += (rs_packet->indicatrix2 & IND2_HFE)   ? 1 : 0;
	if (count > 1) {
		sr_dbg("More than one measurement type detected in packet.");
		return FALSE;
	}

	return TRUE;
}

/*
 * Since the 22-812 does not identify itself in any way, shape, or form,
 * we really don't know for sure who is sending the data. We must use every
 * possible check to filter out bad packets, especially since detection of the
 * 22-812 depends on how well we can filter the packets.
 */
SR_PRIV gboolean sr_rs9lcd_packet_valid(const uint8_t *buf)
{
	const struct rs9lcd_packet *rs_packet = (void *)buf;

	/*
	 * Check for valid mode first, before calculating the checksum. No
	 * point calculating the checksum, if we know we'll reject the packet.
	 */
	if (!(rs_packet->mode < MODE_INVALID))
		return FALSE;

	if (!checksum_valid(rs_packet)) {
		sr_spew("Packet with invalid checksum. Discarding.");
		return FALSE;
	}

	if (!selection_good(rs_packet)) {
		sr_spew("Packet with invalid selection bits. Discarding.");
		return FALSE;
	}

	return TRUE;
}

static uint8_t decode_digit(uint8_t raw_digit)
{
	/* Take out the decimal point, so we can use a simple switch(). */
	raw_digit &= ~DP_MASK;

	switch (raw_digit) {
	case 0x00:
	case LCD_0:
		return 0;
	case LCD_1:
		return 1;
	case LCD_2:
		return 2;
	case LCD_3:
		return 3;
	case LCD_4:
		return 4;
	case LCD_5:
		return 5;
	case LCD_6:
		return 6;
	case LCD_7:
		return 7;
	case LCD_8:
		return 8;
	case LCD_9:
		return 9;
	default:
		sr_dbg("Invalid digit byte: 0x%02x.", raw_digit);
		return 0xff;
	}
}

static double lcd_to_double(const struct rs9lcd_packet *rs_packet, int type,
			    int *exponent)
{
	double rawval = 0;
	uint8_t digit, raw_digit;
	gboolean dp_reached = FALSE;
	int i, end;

	*exponent = 0;

	/* end = 1: Don't parse last digit. end = 0: Parse all digits. */
	end = (type == READ_TEMP) ? 1 : 0;

	/* We have 4 digits, and we start from the most significant. */
	for (i = 3; i >= end; i--) {
		raw_digit = *(&(rs_packet->digit4) + i);
		digit = decode_digit(raw_digit);
		if (digit == 0xff) {
			rawval = NAN;
			break;
		}
		/*
		 * Digit 1 does not have a decimal point. Instead, the decimal
		 * point is used to indicate MAX, so we must avoid testing it.
		 */
		if ((i < 3) && (raw_digit & DP_MASK))
			dp_reached = TRUE;
		if (dp_reached)
			*exponent -= 1;
		rawval = rawval * 10 + digit;
	}
	if (rs_packet->info & INFO_NEG)
		rawval *= -1;

	/* See if we need to multiply our raw value by anything. */
	if (rs_packet->indicatrix2 & IND2_NANO)
		*exponent -= 9;
	else if (rs_packet->indicatrix2 & IND2_MICRO)
		*exponent -= 6;
	else if (rs_packet->indicatrix1 & IND1_MILI)
		*exponent -= 3;
	else if (rs_packet->indicatrix1 & IND1_KILO)
		*exponent += 3;
	else if (rs_packet->indicatrix1 & IND1_MEGA)
		*exponent += 6;

	return rawval * powf(10, *exponent);
}

static gboolean is_celsius(const struct rs9lcd_packet *rs_packet)
{
	return ((rs_packet->digit4 & ~DP_MASK) == LCD_C);
}

static gboolean is_shortcirc(const struct rs9lcd_packet *rs_packet)
{
	return ((rs_packet->digit2 & ~DP_MASK) == LCD_h);
}

static gboolean is_logic_high(const struct rs9lcd_packet *rs_packet)
{
	sr_spew("Digit 2: 0x%02x.", rs_packet->digit2 & ~DP_MASK);
	return ((rs_packet->digit2 & ~DP_MASK) == LCD_H);
}

SR_PRIV int sr_rs9lcd_parse(const uint8_t *buf, float *floatval,
			    struct sr_datafeed_analog *analog, void *info)
{
	const struct rs9lcd_packet *rs_packet = (void *)buf;
	int exponent;
	double rawval;

	(void)info;

	rawval = lcd_to_double(rs_packet, READ_ALL, &exponent);

	switch (rs_packet->mode) {
	case MODE_DC_V:
		analog->meaning->mq = SR_MQ_VOLTAGE;
		analog->meaning->unit = SR_UNIT_VOLT;
		analog->meaning->mqflags |= SR_MQFLAG_DC;
		break;
	case MODE_AC_V:
		analog->meaning->mq = SR_MQ_VOLTAGE;
		analog->meaning->unit = SR_UNIT_VOLT;
		analog->meaning->mqflags |= SR_MQFLAG_AC;
		break;
	case MODE_DC_UA:	/* Fall through */
	case MODE_DC_MA:	/* Fall through */
	case MODE_DC_A:
		analog->meaning->mq = SR_MQ_CURRENT;
		analog->meaning->unit = SR_UNIT_AMPERE;
		analog->meaning->mqflags |= SR_MQFLAG_DC;
		break;
	case MODE_AC_UA:	/* Fall through */
	case MODE_AC_MA:	/* Fall through */
	case MODE_AC_A:
		analog->meaning->mq = SR_MQ_CURRENT;
		analog->meaning->unit = SR_UNIT_AMPERE;
		analog->meaning->mqflags |= SR_MQFLAG_AC;
		break;
	case MODE_OHM:
		analog->meaning->mq = SR_MQ_RESISTANCE;
		analog->meaning->unit = SR_UNIT_OHM;
		break;
	case MODE_FARAD:
		analog->meaning->mq = SR_MQ_CAPACITANCE;
		analog->meaning->unit = SR_UNIT_FARAD;
		break;
	case MODE_CONT:
		analog->meaning->mq = SR_MQ_CONTINUITY;
		analog->meaning->unit = SR_UNIT_BOOLEAN;
		rawval = is_shortcirc(rs_packet);
		break;
	case MODE_DIODE:
		analog->meaning->mq = SR_MQ_VOLTAGE;
		analog->meaning->unit = SR_UNIT_VOLT;
		analog->meaning->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
		break;
	case MODE_HZ:		/* Fall through */
	case MODE_VOLT_HZ:	/* Fall through */
	case MODE_AMP_HZ:
		analog->meaning->mq = SR_MQ_FREQUENCY;
		analog->meaning->unit = SR_UNIT_HERTZ;
		break;
	case MODE_LOGIC:
		/*
		 * No matter whether or not we have an actual voltage reading,
		 * we are measuring voltage, so we set our MQ as VOLTAGE.
		 */
		analog->meaning->mq = SR_MQ_VOLTAGE;
		if (!isnan(rawval)) {
			/* We have an actual voltage. */
			analog->meaning->unit = SR_UNIT_VOLT;
		} else {
			/* We have either HI or LOW. */
			analog->meaning->unit = SR_UNIT_BOOLEAN;
			rawval = is_logic_high(rs_packet);
		}
		break;
	case MODE_HFE:
		analog->meaning->mq = SR_MQ_GAIN;
		analog->meaning->unit = SR_UNIT_UNITLESS;
		break;
	case MODE_DUTY:		/* Fall through */
	case MODE_VOLT_DUTY:	/* Fall through */
	case MODE_AMP_DUTY:
		analog->meaning->mq = SR_MQ_DUTY_CYCLE;
		analog->meaning->unit = SR_UNIT_PERCENTAGE;
		break;
	case MODE_WIDTH:	/* Fall through */
	case MODE_VOLT_WIDTH:	/* Fall through */
	case MODE_AMP_WIDTH:
		analog->meaning->mq = SR_MQ_PULSE_WIDTH;
		analog->meaning->unit = SR_UNIT_SECOND;
		break;
	case MODE_TEMP:
		analog->meaning->mq = SR_MQ_TEMPERATURE;
		/* We need to reparse. */
		rawval = lcd_to_double(rs_packet, READ_TEMP, &exponent);
		analog->meaning->unit = is_celsius(rs_packet) ?
				SR_UNIT_CELSIUS : SR_UNIT_FAHRENHEIT;
		break;
	case MODE_DBM:
		analog->meaning->mq = SR_MQ_POWER;
		analog->meaning->unit = SR_UNIT_DECIBEL_MW;
		analog->meaning->mqflags |= SR_MQFLAG_AC;
		break;
	default:
		sr_dbg("Unknown mode: %d.", rs_packet->mode);
		break;
	}

	if (rs_packet->info & INFO_HOLD)
		analog->meaning->mqflags |= SR_MQFLAG_HOLD;
	if (rs_packet->digit4 & DIG4_MAX)
		analog->meaning->mqflags |= SR_MQFLAG_MAX;
	if (rs_packet->indicatrix2 & IND2_MIN)
		analog->meaning->mqflags |= SR_MQFLAG_MIN;
	if (rs_packet->info & INFO_AUTO)
		analog->meaning->mqflags |= SR_MQFLAG_AUTORANGE;

	*floatval = rawval;

	analog->encoding->digits = -exponent;
	analog->spec->spec_digits = -exponent;

	return SR_OK;
}
Commit	Line	Data
05f134ab	1	/*
50985c20	2	* This file is part of the libsigrok project.
05f134ab AG	3	*
	4	* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
	5	*
	6	* This program is free software: you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation, either version 3 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	/*
	21	* RadioShack 22-812 protocol parser.
	22	*
	23	* This protocol is currently encountered on the RadioShack 22-812 DMM.
	24	* It is a 9-byte packet representing a 1:1 mapping of the LCD segments, hence
	25	* the name rs9lcd.
	26	*
	27	* The chip is a bare die covered by a plastic blob. It is unclear if this chip
	28	* and protocol is used on any other device.
	29	*/
	30
6ec6c43b	31	#include <config.h>
05f134ab AG	32	#include <string.h>
	33	#include <ctype.h>
	34	#include <math.h>
	35	#include <glib.h>
c1aae900	36	#include <libsigrok/libsigrok.h>
05f134ab AG	37	#include "libsigrok-internal.h"
05f134ab AG	38
b95dd761	39	#define LOG_PREFIX "rs9lcd"
05f134ab AG	40
05f134ab AG	41	/* Byte 1 of the packet, and the modes it represents */
0853d5e6 AG	42	#define IND1_HZ (1 << 7)
	43	#define IND1_OHM (1 << 6)
	44	#define IND1_KILO (1 << 5)
	45	#define IND1_MEGA (1 << 4)
	46	#define IND1_FARAD (1 << 3)
	47	#define IND1_AMP (1 << 2)
	48	#define IND1_VOLT (1 << 1)
	49	#define IND1_MILI (1 << 0)
05f134ab	50	/* Byte 2 of the packet, and the modes it represents */
0853d5e6 AG	51	#define IND2_MICRO (1 << 7)
	52	#define IND2_NANO (1 << 6)
	53	#define IND2_DBM (1 << 5)
	54	#define IND2_SEC (1 << 4)
	55	#define IND2_DUTY (1 << 3)
	56	#define IND2_HFE (1 << 2)
	57	#define IND2_REL (1 << 1)
	58	#define IND2_MIN (1 << 0)
05f134ab	59	/* Byte 7 of the packet, and the modes it represents */
0853d5e6 AG	60	#define INFO_BEEP (1 << 7)
	61	#define INFO_DIODE (1 << 6)
	62	#define INFO_BAT (1 << 5)
	63	#define INFO_HOLD (1 << 4)
	64	#define INFO_NEG (1 << 3)
	65	#define INFO_AC (1 << 2)
	66	#define INFO_RS232 (1 << 1)
	67	#define INFO_AUTO (1 << 0)
05f134ab	68	/* Instead of a decimal point, digit 4 carries the MAX flag */
0853d5e6	69	#define DIG4_MAX (1 << 3)
05f134ab	70	/* Mask to remove the decimal point from a digit */
0853d5e6	71	#define DP_MASK (1 << 3)
05f134ab AG	72
	73	/* What the LCD values represent */
	74	#define LCD_0 0xd7
	75	#define LCD_1 0x50
	76	#define LCD_2 0xb5
	77	#define LCD_3 0xf1
	78	#define LCD_4 0x72
	79	#define LCD_5 0xe3
	80	#define LCD_6 0xe7
	81	#define LCD_7 0x51
	82	#define LCD_8 0xf7
	83	#define LCD_9 0xf3
	84
	85	#define LCD_C 0x87
	86	#define LCD_E
	87	#define LCD_F
	88	#define LCD_h 0x66
	89	#define LCD_H 0x76
	90	#define LCD_I
	91	#define LCD_n
	92	#define LCD_P 0x37
	93	#define LCD_r
	94
	95	enum {
	96	MODE_DC_V = 0,
	97	MODE_AC_V = 1,
	98	MODE_DC_UA = 2,
	99	MODE_DC_MA = 3,
	100	MODE_DC_A = 4,
	101	MODE_AC_UA = 5,
	102	MODE_AC_MA = 6,
	103	MODE_AC_A = 7,
	104	MODE_OHM = 8,
	105	MODE_FARAD = 9,
	106	MODE_HZ = 10,
0853d5e6 AG	107	MODE_VOLT_HZ = 11, /* Dial set to V, Hz selected by Hz button */
0853d5e6 AG	108	MODE_AMP_HZ = 12, /* Dial set to A, Hz selected by Hz button */
05f134ab	109	MODE_DUTY = 13,
0853d5e6 AG	110	MODE_VOLT_DUTY = 14, /* Dial set to V, duty cycle selected */
0853d5e6 AG	111	MODE_AMP_DUTY = 15, /* Dial set to A, duty cycle selected */
05f134ab	112	MODE_WIDTH = 16,
0853d5e6 AG	113	MODE_VOLT_WIDTH = 17, /* Dial set to V, pulse width selected */
0853d5e6 AG	114	MODE_AMP_WIDTH = 18, /* Dial set to A, pulse width selected */
05f134ab AG	115	MODE_DIODE = 19,
	116	MODE_CONT = 20,
	117	MODE_HFE = 21,
	118	MODE_LOGIC = 22,
	119	MODE_DBM = 23,
0853d5e6	120	/* MODE_EF = 24, / / Not encountered on any DMM */
05f134ab AG	121	MODE_TEMP = 25,
	122	MODE_INVALID = 26,
	123	};
	124
	125	enum {
	126	READ_ALL,
	127	READ_TEMP,
	128	};
	129
	130	struct rs9lcd_packet {
	131	uint8_t mode;
	132	uint8_t indicatrix1;
	133	uint8_t indicatrix2;
	134	uint8_t digit4;
	135	uint8_t digit3;
	136	uint8_t digit2;
	137	uint8_t digit1;
	138	uint8_t info;
	139	uint8_t checksum;
	140	};
	141
	142	static gboolean checksum_valid(const struct rs9lcd_packet *rs_packet)
	143	{
	144	uint8_t *raw;
	145	uint8_t sum = 0;
	146	int i;
	147
	148	raw = (void *)rs_packet;
	149
21829e67	150	for (i = 0; i < RS9LCD_PACKET_SIZE - 1; i++)
05f134ab AG	151	sum += raw[i];
	152
	153	/* This is just a funky constant added to the checksum. */
	154	sum += 57;
	155	sum -= rs_packet->checksum;
	156	return (sum == 0);
	157	}
	158
	159	static gboolean selection_good(const struct rs9lcd_packet *rs_packet)
	160	{
	161	int count;
	162
	163	/* Does the packet have more than one multiplier? */
	164	count = 0;
	165	count += (rs_packet->indicatrix1 & IND1_KILO) ? 1 : 0;
	166	count += (rs_packet->indicatrix1 & IND1_MEGA) ? 1 : 0;
	167	count += (rs_packet->indicatrix1 & IND1_MILI) ? 1 : 0;
	168	count += (rs_packet->indicatrix2 & IND2_MICRO) ? 1 : 0;
	169	count += (rs_packet->indicatrix2 & IND2_NANO) ? 1 : 0;
	170	if (count > 1) {
ec5186f9	171	sr_dbg("More than one multiplier detected in packet.");
05f134ab AG	172	return FALSE;
	173	}
	174
	175	/* Does the packet "measure" more than one type of value? */
	176	count = 0;
	177	count += (rs_packet->indicatrix1 & IND1_HZ) ? 1 : 0;
	178	count += (rs_packet->indicatrix1 & IND1_OHM) ? 1 : 0;
	179	count += (rs_packet->indicatrix1 & IND1_FARAD) ? 1 : 0;
	180	count += (rs_packet->indicatrix1 & IND1_AMP) ? 1 : 0;
	181	count += (rs_packet->indicatrix1 & IND1_VOLT) ? 1 : 0;
	182	count += (rs_packet->indicatrix2 & IND2_DBM) ? 1 : 0;
	183	count += (rs_packet->indicatrix2 & IND2_SEC) ? 1 : 0;
	184	count += (rs_packet->indicatrix2 & IND2_DUTY) ? 1 : 0;
	185	count += (rs_packet->indicatrix2 & IND2_HFE) ? 1 : 0;
	186	if (count > 1) {
ec5186f9	187	sr_dbg("More than one measurement type detected in packet.");
05f134ab AG	188	return FALSE;
	189	}
	190
	191	return TRUE;
	192	}
	193
	194	/*
	195	* Since the 22-812 does not identify itself in any way, shape, or form,
	196	* we really don't know for sure who is sending the data. We must use every
	197	* possible check to filter out bad packets, especially since detection of the
	198	* 22-812 depends on how well we can filter the packets.
	199	*/
	200	SR_PRIV gboolean sr_rs9lcd_packet_valid(const uint8_t *buf)
	201	{
	202	const struct rs9lcd_packet rs_packet = (void )buf;
	203
	204	/*
	205	* Check for valid mode first, before calculating the checksum. No
	206	* point calculating the checksum, if we know we'll reject the packet.
	207	*/
	208	if (!(rs_packet->mode < MODE_INVALID))
	209	return FALSE;
	210
	211	if (!checksum_valid(rs_packet)) {
	212	sr_spew("Packet with invalid checksum. Discarding.");
	213	return FALSE;
	214	}
	215
	216	if (!selection_good(rs_packet)) {
	217	sr_spew("Packet with invalid selection bits. Discarding.");
	218	return FALSE;
	219	}
	220
	221	return TRUE;
	222	}
	223
	224	static uint8_t decode_digit(uint8_t raw_digit)
	225	{
	226	/* Take out the decimal point, so we can use a simple switch(). */
	227	raw_digit &= ~DP_MASK;
	228
	229	switch (raw_digit) {
	230	case 0x00:
	231	case LCD_0:
	232	return 0;
	233	case LCD_1:
	234	return 1;
	235	case LCD_2:
	236	return 2;
	237	case LCD_3:
	238	return 3;
	239	case LCD_4:
	240	return 4;
	241	case LCD_5:
	242	return 5;
	243	case LCD_6:
	244	return 6;
	245	case LCD_7:
	246	return 7;
	247	case LCD_8:
	248	return 8;
	249	case LCD_9:
	250	return 9;
	251	default:
ec5186f9	252	sr_dbg("Invalid digit byte: 0x%02x.", raw_digit);
05f134ab AG	253	return 0xff;
	254	}
	255	}
	256
96a06b42 AJ	257	static double lcd_to_double(const struct rs9lcd_packet *rs_packet, int type,
96a06b42 AJ	258	int *exponent)
05f134ab	259	{
96a06b42	260	double rawval = 0;
05f134ab AG	261	uint8_t digit, raw_digit;
	262	gboolean dp_reached = FALSE;
	263	int i, end;
	264
96a06b42 AJ	265	*exponent = 0;
96a06b42 AJ	266
05f134ab AG	267	/* end = 1: Don't parse last digit. end = 0: Parse all digits. */
	268	end = (type == READ_TEMP) ? 1 : 0;
	269
	270	/* We have 4 digits, and we start from the most significant. */
	271	for (i = 3; i >= end; i--) {
	272	raw_digit = *(&(rs_packet->digit4) + i);
	273	digit = decode_digit(raw_digit);
	274	if (digit == 0xff) {
	275	rawval = NAN;
	276	break;
	277	}
	278	/*
	279	* Digit 1 does not have a decimal point. Instead, the decimal
	280	* point is used to indicate MAX, so we must avoid testing it.
	281	*/
	282	if ((i < 3) && (raw_digit & DP_MASK))
	283	dp_reached = TRUE;
	284	if (dp_reached)
96a06b42	285	*exponent -= 1;
05f134ab AG	286	rawval = rawval * 10 + digit;
05f134ab AG	287	}
05f134ab AG	288	if (rs_packet->info & INFO_NEG)
	289	rawval *= -1;
	290
	291	/* See if we need to multiply our raw value by anything. */
6703bb29	292	if (rs_packet->indicatrix2 & IND2_NANO)
96a06b42	293	*exponent -= 9;
05f134ab	294	else if (rs_packet->indicatrix2 & IND2_MICRO)
96a06b42	295	*exponent -= 6;
05f134ab	296	else if (rs_packet->indicatrix1 & IND1_MILI)
96a06b42	297	*exponent -= 3;
05f134ab	298	else if (rs_packet->indicatrix1 & IND1_KILO)
96a06b42	299	*exponent += 3;
05f134ab	300	else if (rs_packet->indicatrix1 & IND1_MEGA)
96a06b42	301	*exponent += 6;
05f134ab	302
96a06b42	303	return rawval * powf(10, *exponent);
05f134ab AG	304	}
	305
	306	static gboolean is_celsius(const struct rs9lcd_packet *rs_packet)
	307	{
	308	return ((rs_packet->digit4 & ~DP_MASK) == LCD_C);
	309	}
	310
	311	static gboolean is_shortcirc(const struct rs9lcd_packet *rs_packet)
	312	{
	313	return ((rs_packet->digit2 & ~DP_MASK) == LCD_h);
	314	}
	315
	316	static gboolean is_logic_high(const struct rs9lcd_packet *rs_packet)
	317	{
	318	sr_spew("Digit 2: 0x%02x.", rs_packet->digit2 & ~DP_MASK);
	319	return ((rs_packet->digit2 & ~DP_MASK) == LCD_H);
	320	}
	321
	322	SR_PRIV int sr_rs9lcd_parse(const uint8_t buf, float floatval,
b02bb45f	323	struct sr_datafeed_analog analog, void info)
05f134ab AG	324	{
05f134ab AG	325	const struct rs9lcd_packet rs_packet = (void )buf;
96a06b42	326	int exponent;
05f134ab AG	327	double rawval;
	328
	329	(void)info;
	330
96a06b42	331	rawval = lcd_to_double(rs_packet, READ_ALL, &exponent);
05f134ab AG	332
	333	switch (rs_packet->mode) {
	334	case MODE_DC_V:
b02bb45f UH	335	analog->meaning->mq = SR_MQ_VOLTAGE;
	336	analog->meaning->unit = SR_UNIT_VOLT;
	337	analog->meaning->mqflags \|= SR_MQFLAG_DC;
05f134ab AG	338	break;
05f134ab AG	339	case MODE_AC_V:
b02bb45f UH	340	analog->meaning->mq = SR_MQ_VOLTAGE;
	341	analog->meaning->unit = SR_UNIT_VOLT;
	342	analog->meaning->mqflags \|= SR_MQFLAG_AC;
05f134ab	343	break;
0853d5e6 AG	344	case MODE_DC_UA: /* Fall through */
0853d5e6 AG	345	case MODE_DC_MA: /* Fall through */
05f134ab	346	case MODE_DC_A:
b02bb45f UH	347	analog->meaning->mq = SR_MQ_CURRENT;
	348	analog->meaning->unit = SR_UNIT_AMPERE;
	349	analog->meaning->mqflags \|= SR_MQFLAG_DC;
05f134ab	350	break;
0853d5e6 AG	351	case MODE_AC_UA: /* Fall through */
0853d5e6 AG	352	case MODE_AC_MA: /* Fall through */
05f134ab	353	case MODE_AC_A:
b02bb45f UH	354	analog->meaning->mq = SR_MQ_CURRENT;
	355	analog->meaning->unit = SR_UNIT_AMPERE;
	356	analog->meaning->mqflags \|= SR_MQFLAG_AC;
05f134ab AG	357	break;
05f134ab AG	358	case MODE_OHM:
b02bb45f UH	359	analog->meaning->mq = SR_MQ_RESISTANCE;
b02bb45f UH	360	analog->meaning->unit = SR_UNIT_OHM;
05f134ab AG	361	break;
05f134ab AG	362	case MODE_FARAD:
b02bb45f UH	363	analog->meaning->mq = SR_MQ_CAPACITANCE;
b02bb45f UH	364	analog->meaning->unit = SR_UNIT_FARAD;
05f134ab AG	365	break;
05f134ab AG	366	case MODE_CONT:
b02bb45f UH	367	analog->meaning->mq = SR_MQ_CONTINUITY;
b02bb45f UH	368	analog->meaning->unit = SR_UNIT_BOOLEAN;
47eda193	369	rawval = is_shortcirc(rs_packet);
05f134ab AG	370	break;
05f134ab AG	371	case MODE_DIODE:
b02bb45f UH	372	analog->meaning->mq = SR_MQ_VOLTAGE;
	373	analog->meaning->unit = SR_UNIT_VOLT;
	374	analog->meaning->mqflags \|= SR_MQFLAG_DIODE \| SR_MQFLAG_DC;
05f134ab	375	break;
0853d5e6 AG	376	case MODE_HZ: /* Fall through */
0853d5e6 AG	377	case MODE_VOLT_HZ: /* Fall through */
05f134ab	378	case MODE_AMP_HZ:
b02bb45f UH	379	analog->meaning->mq = SR_MQ_FREQUENCY;
b02bb45f UH	380	analog->meaning->unit = SR_UNIT_HERTZ;
05f134ab AG	381	break;
	382	case MODE_LOGIC:
	383	/*
	384	* No matter whether or not we have an actual voltage reading,
	385	* we are measuring voltage, so we set our MQ as VOLTAGE.
	386	*/
b02bb45f	387	analog->meaning->mq = SR_MQ_VOLTAGE;
05f134ab AG	388	if (!isnan(rawval)) {
05f134ab AG	389	/* We have an actual voltage. */
b02bb45f	390	analog->meaning->unit = SR_UNIT_VOLT;
05f134ab AG	391	} else {
05f134ab AG	392	/* We have either HI or LOW. */
b02bb45f	393	analog->meaning->unit = SR_UNIT_BOOLEAN;
47eda193	394	rawval = is_logic_high(rs_packet);
05f134ab AG	395	}
	396	break;
	397	case MODE_HFE:
b02bb45f UH	398	analog->meaning->mq = SR_MQ_GAIN;
b02bb45f UH	399	analog->meaning->unit = SR_UNIT_UNITLESS;
05f134ab	400	break;
0853d5e6 AG	401	case MODE_DUTY: /* Fall through */
0853d5e6 AG	402	case MODE_VOLT_DUTY: /* Fall through */
05f134ab	403	case MODE_AMP_DUTY:
b02bb45f UH	404	analog->meaning->mq = SR_MQ_DUTY_CYCLE;
b02bb45f UH	405	analog->meaning->unit = SR_UNIT_PERCENTAGE;
05f134ab	406	break;
0853d5e6 AG	407	case MODE_WIDTH: /* Fall through */
0853d5e6 AG	408	case MODE_VOLT_WIDTH: /* Fall through */
05f134ab	409	case MODE_AMP_WIDTH:
b02bb45f UH	410	analog->meaning->mq = SR_MQ_PULSE_WIDTH;
b02bb45f UH	411	analog->meaning->unit = SR_UNIT_SECOND;
cbc8cbd8	412	break;
05f134ab	413	case MODE_TEMP:
b02bb45f	414	analog->meaning->mq = SR_MQ_TEMPERATURE;
05f134ab	415	/* We need to reparse. */
96a06b42	416	rawval = lcd_to_double(rs_packet, READ_TEMP, &exponent);
b02bb45f	417	analog->meaning->unit = is_celsius(rs_packet) ?
05f134ab AG	418	SR_UNIT_CELSIUS : SR_UNIT_FAHRENHEIT;
	419	break;
	420	case MODE_DBM:
b02bb45f UH	421	analog->meaning->mq = SR_MQ_POWER;
	422	analog->meaning->unit = SR_UNIT_DECIBEL_MW;
	423	analog->meaning->mqflags \|= SR_MQFLAG_AC;
05f134ab AG	424	break;
05f134ab AG	425	default:
ec5186f9	426	sr_dbg("Unknown mode: %d.", rs_packet->mode);
05f134ab AG	427	break;
	428	}
	429
	430	if (rs_packet->info & INFO_HOLD)
b02bb45f	431	analog->meaning->mqflags \|= SR_MQFLAG_HOLD;
05f134ab	432	if (rs_packet->digit4 & DIG4_MAX)
b02bb45f	433	analog->meaning->mqflags \|= SR_MQFLAG_MAX;
05f134ab	434	if (rs_packet->indicatrix2 & IND2_MIN)
b02bb45f	435	analog->meaning->mqflags \|= SR_MQFLAG_MIN;
05f134ab	436	if (rs_packet->info & INFO_AUTO)
b02bb45f	437	analog->meaning->mqflags \|= SR_MQFLAG_AUTORANGE;
05f134ab AG	438
05f134ab AG	439	*floatval = rawval;
96a06b42	440
d9251a2c	441	analog->encoding->digits = -exponent;
96a06b42 AJ	442	analog->spec->spec_digits = -exponent;
96a06b42 AJ	443
05f134ab AG	444	return SR_OK;
05f134ab AG	445	}