[libsigrok.git] / hardware / radioshack-dmm / protocol.c

/*
 * This file is part of the sigrok project.
 *
 * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
 * 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/>.
 */

#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <errno.h>
#include <glib.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"
#include "protocol.h"

/* Byte 1 of the packet, and the modes it represents */
#define IND1_HZ		0x80
#define IND1_OHM	0x40
#define IND1_KILO	0x20
#define IND1_MEGA	0x10
#define IND1_FARAD	0x08
#define IND1_AMP	0x04
#define IND1_VOLT	0x02
#define IND1_MILI	0x01
/* Byte 2 of the packet, and the modes it represents */
#define IND2_MICRO	0x80
#define IND2_NANO	0x40
#define IND2_DBM	0x20
#define IND2_SEC	0x10
#define IND2_DUTY	0x08
#define IND2_HFE	0x04
#define IND2_REL	0x02
#define IND2_MIN	0x01
/* Byte 7 of the packet, and the modes it represents */
#define INFO_BEEP	0x80
#define INFO_DIODE	0x30
#define INFO_BAT	0x20
#define INFO_HOLD	0x10
#define INFO_NEG	0x08
#define INFO_AC		0x04
#define INFO_RS232	0x02
#define INFO_AUTO	0x01
/* Instead of a decimal point, digit 4 carries the MAX flag */
#define DIG4_MAX	0x08
/* Mask to remove the decimal point from a digit */
#define DP_MASK		0x08

/* 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,
	MODE_AMP_HZ	= 12,
	MODE_DUTY	= 13,
	MODE_VOLT_DUTY	= 14,
	MODE_AMP_DUTY	= 15,
	MODE_WIDTH	= 16,
	MODE_VOLT_WIDTH	= 17,
	MODE_AMP_WIDTH	= 18,
	MODE_DIODE	= 19,
	MODE_CONT	= 20,
	MODE_HFE	= 21,
	MODE_LOGIC	= 22,
	MODE_DBM	= 23,
	// MODE_EF	= 24,
	MODE_TEMP	= 25,
	MODE_INVALID	= 26,
};

enum {
	READ_ALL,
	READ_TEMP,
};

static gboolean checksum_valid(const struct rs_22_812_packet *rs_packet)
{
	uint8_t *raw;
	uint8_t sum = 0;
	int i;

	raw = (void *)rs_packet;

	for (i = 0; i < RS_22_812_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 rs_22_812_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_err("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_err("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 rs_22_812_packet_valid(const struct rs_22_812_packet *rs_packet)
{
	/*
	 * 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_err("Invalid digit byte: 0x%02x.", raw_digit);
		return 0xff;
	}
}

static double lcd_to_double(const struct rs_22_812_packet *rs_packet, int type)
{
	double rawval, multiplier = 1;
	uint8_t digit, raw_digit;
	gboolean dp_reached = FALSE;
	int i, end;

	/* 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)
			multiplier /= 10;
		rawval = rawval * 10 + digit;
	}
	rawval *= multiplier;
	if (rs_packet->info & INFO_NEG)
		rawval *= -1;

	/* See if we need to multiply our raw value by anything. */
	if (rs_packet->indicatrix1 & IND2_NANO) {
		rawval *= 1E-9;
	} else if (rs_packet->indicatrix2 & IND2_MICRO) {
		rawval *= 1E-6;
	} else if (rs_packet->indicatrix1 & IND1_MILI) {
		rawval *= 1E-3;
	} else if (rs_packet->indicatrix1 & IND1_KILO) {
		rawval *= 1E3;
	} else if (rs_packet->indicatrix1 & IND1_MEGA) {
		rawval *= 1E6;
	}

	return rawval;
}

static gboolean is_celsius(struct rs_22_812_packet *rs_packet)
{
	return ((rs_packet->digit4 & ~DP_MASK) == LCD_C);
}

static gboolean is_shortcirc(struct rs_22_812_packet *rs_packet)
{
	return ((rs_packet->digit2 & ~DP_MASK) == LCD_h);
}

static gboolean is_logic_high(struct rs_22_812_packet *rs_packet)
{
	sr_spew("Digit 2: 0x%02x.", rs_packet->digit2 & ~DP_MASK);
	return ((rs_packet->digit2 & ~DP_MASK) == LCD_H);
}

static void handle_packet(struct rs_22_812_packet *rs_packet,
			  struct dev_context *devc)
{
	double rawval;
	struct sr_datafeed_packet packet;
	struct sr_datafeed_analog *analog;

	rawval = lcd_to_double(rs_packet, READ_ALL);

	/* TODO: Check malloc return value. */
	analog = g_try_malloc0(sizeof(struct sr_datafeed_analog));
	analog->num_samples = 1;
	/* TODO: Check malloc return value. */
	analog->data = g_try_malloc(sizeof(float));
	*analog->data = (float)rawval;
	analog->mq = -1;

	switch (rs_packet->mode) {
	case MODE_DC_V:
		analog->mq = SR_MQ_VOLTAGE;
		analog->unit = SR_UNIT_VOLT;
		analog->mqflags |= SR_MQFLAG_DC;
		break;
	case MODE_AC_V:
		analog->mq = SR_MQ_VOLTAGE;
		analog->unit = SR_UNIT_VOLT;
		analog->mqflags |= SR_MQFLAG_AC;
		break;
	case MODE_DC_UA:
	case MODE_DC_MA:
	case MODE_DC_A:
		analog->mq = SR_MQ_CURRENT;
		analog->unit = SR_UNIT_AMPERE;
		analog->mqflags |= SR_MQFLAG_DC;
		break;
	case MODE_AC_UA:
	case MODE_AC_MA:
	case MODE_AC_A:
		analog->mq = SR_MQ_CURRENT;
		analog->unit = SR_UNIT_AMPERE;
		analog->mqflags |= SR_MQFLAG_AC;
		break;
	case MODE_OHM:
		analog->mq = SR_MQ_RESISTANCE;
		analog->unit = SR_UNIT_OHM;
		break;
	case MODE_FARAD:
		analog->mq = SR_MQ_CAPACITANCE;
		analog->unit = SR_UNIT_FARAD;
		break;
	case MODE_CONT:
		analog->mq = SR_MQ_CONTINUITY;
		analog->unit = SR_UNIT_BOOLEAN;
		*analog->data = is_shortcirc(rs_packet);
		break;
	case MODE_DIODE:
		analog->mq = SR_MQ_VOLTAGE;
		analog->unit = SR_UNIT_VOLT;
		analog->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
		break;
	case MODE_HZ:
	case MODE_VOLT_HZ:
	case MODE_AMP_HZ:
		analog->mq = SR_MQ_FREQUENCY;
		analog->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->mq = SR_MQ_VOLTAGE;
		if (!isnan(rawval)) {
			/* We have an actual voltage. */
			analog->unit = SR_UNIT_VOLT;
		} else {
			/* We have either HI or LOW. */
			analog->unit = SR_UNIT_BOOLEAN;
			*analog->data = is_logic_high(rs_packet);
		}
		break;
	case MODE_HFE:
		analog->mq = SR_MQ_GAIN;
		analog->unit = SR_UNIT_UNITLESS;
		break;
	case MODE_DUTY:
	case MODE_VOLT_DUTY:
	case MODE_AMP_DUTY:
		analog->mq = SR_MQ_DUTY_CYCLE;
		analog->unit = SR_UNIT_PERCENTAGE;
		break;
	case MODE_WIDTH:
	case MODE_VOLT_WIDTH:
	case MODE_AMP_WIDTH:
		analog->mq = SR_MQ_PULSE_WIDTH;
		analog->unit = SR_UNIT_SECOND;
	case MODE_TEMP:
		analog->mq = SR_MQ_TEMPERATURE;
		/* We need to reparse. */
		*analog->data = lcd_to_double(rs_packet, READ_TEMP);
		analog->unit = is_celsius(rs_packet) ?
		               SR_UNIT_CELSIUS : SR_UNIT_FAHRENHEIT;
		break;
	case MODE_DBM:
		analog->mq = SR_MQ_POWER;
		analog->unit = SR_UNIT_DECIBEL_MW;
		analog->mqflags |= SR_MQFLAG_AC;
		break;
	default:
		sr_err("Unknown mode: %d.", rs_packet->mode);
		break;
	}

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

	if (analog->mq != -1) {
		/* Got a measurement. */
		sr_spew("Value: %f.", rawval);
		packet.type = SR_DF_ANALOG;
		packet.payload = analog;
		sr_session_send(devc->cb_data, &packet);
		devc->num_samples++;
	}
	g_free(analog->data);
	g_free(analog);
}

static void handle_new_data(struct dev_context *devc)
{
	int len;
	size_t i, offset = 0;
	struct rs_22_812_packet *rs_packet;

	/* Try to get as much data as the buffer can hold. */
	len = RS_DMM_BUFSIZE - devc->buflen;
	len = serial_read(devc->serial, devc->buf + devc->buflen, len);
	if (len < 1) {
		sr_err("Serial port read error.");
		return;
	}
	devc->buflen += len;

	/* Now look for packets in that data. */
	while ((devc->buflen - offset) >= RS_22_812_PACKET_SIZE) {
		rs_packet = (void *)(devc->buf + offset);
		if (rs_22_812_packet_valid(rs_packet)) {
			handle_packet(rs_packet, devc);
			offset += RS_22_812_PACKET_SIZE;
		} else {
			offset++;
		}
	}

	/* If we have any data left, move it to the beginning of our buffer. */
	for (i = 0; i < devc->buflen - offset; i++)
		devc->buf[i] = devc->buf[offset + i];
	devc->buflen -= offset;
}

SR_PRIV int radioshack_dmm_receive_data(int fd, int revents, void *cb_data)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;

	(void)fd;

	if (!(sdi = cb_data))
		return TRUE;

	if (!(devc = sdi->priv))
		return TRUE;

	if (revents == G_IO_IN) {
		/* Serial data arrived. */
		handle_new_data(devc);
	}

	if (devc->num_samples >= devc->limit_samples) {
		sdi->driver->dev_acquisition_stop(sdi, cb_data);
		return TRUE;
	}

	return TRUE;
}
Commit	Line	Data
d375b3c3 AG	1	/*
	2	* This file is part of the sigrok project.
	3	*
	4	* Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
	5	* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
	6	*
	7	* This program is free software: you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation, either version 3 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	19	*/
	20
d375b3c3 AG	21	#include <stdlib.h>
	22	#include <math.h>
	23	#include <string.h>
	24	#include <errno.h>
ba6383f8 UH	25	#include <glib.h>
	26	#include "libsigrok.h"
	27	#include "libsigrok-internal.h"
936e27f1	28	#include "protocol.h"
ba6383f8	29
4e172b8f UH	30	/* Byte 1 of the packet, and the modes it represents */
	31	#define IND1_HZ 0x80
	32	#define IND1_OHM 0x40
	33	#define IND1_KILO 0x20
	34	#define IND1_MEGA 0x10
	35	#define IND1_FARAD 0x08
	36	#define IND1_AMP 0x04
	37	#define IND1_VOLT 0x02
	38	#define IND1_MILI 0x01
	39	/* Byte 2 of the packet, and the modes it represents */
	40	#define IND2_MICRO 0x80
	41	#define IND2_NANO 0x40
	42	#define IND2_DBM 0x20
	43	#define IND2_SEC 0x10
	44	#define IND2_DUTY 0x08
	45	#define IND2_HFE 0x04
	46	#define IND2_REL 0x02
	47	#define IND2_MIN 0x01
	48	/* Byte 7 of the packet, and the modes it represents */
	49	#define INFO_BEEP 0x80
	50	#define INFO_DIODE 0x30
	51	#define INFO_BAT 0x20
	52	#define INFO_HOLD 0x10
	53	#define INFO_NEG 0x08
	54	#define INFO_AC 0x04
	55	#define INFO_RS232 0x02
	56	#define INFO_AUTO 0x01
	57	/* Instead of a decimal point, digit 4 carries the MAX flag */
	58	#define DIG4_MAX 0x08
	59	/* Mask to remove the decimal point from a digit */
	60	#define DP_MASK 0x08
	61
	62	/* What the LCD values represent */
	63	#define LCD_0 0xd7
	64	#define LCD_1 0x50
	65	#define LCD_2 0xb5
	66	#define LCD_3 0xf1
	67	#define LCD_4 0x72
	68	#define LCD_5 0xe3
	69	#define LCD_6 0xe7
	70	#define LCD_7 0x51
	71	#define LCD_8 0xf7
	72	#define LCD_9 0xf3
	73
	74	#define LCD_C 0x87
	75	#define LCD_E
	76	#define LCD_F
	77	#define LCD_h 0x66
	78	#define LCD_H 0x76
	79	#define LCD_I
	80	#define LCD_n
	81	#define LCD_P 0x37
	82	#define LCD_r
	83
	84	enum {
	85	MODE_DC_V = 0,
	86	MODE_AC_V = 1,
	87	MODE_DC_UA = 2,
	88	MODE_DC_MA = 3,
	89	MODE_DC_A = 4,
	90	MODE_AC_UA = 5,
	91	MODE_AC_MA = 6,
	92	MODE_AC_A = 7,
	93	MODE_OHM = 8,
94	MODE_FARAD = 9,
95	MODE_HZ = 10,
96	MODE_VOLT_HZ = 11,
97	MODE_AMP_HZ = 12,
98	MODE_DUTY = 13,
99	MODE_VOLT_DUTY = 14,
100	MODE_AMP_DUTY = 15,
101	MODE_WIDTH = 16,
102	MODE_VOLT_WIDTH = 17,
103	MODE_AMP_WIDTH = 18,
104	MODE_DIODE = 19,
105	MODE_CONT = 20,
106	MODE_HFE = 21,
107	MODE_LOGIC = 22,
108	MODE_DBM = 23,
109	// MODE_EF = 24,
110	MODE_TEMP = 25,
111	MODE_INVALID = 26,
112	};
113
ba6383f8 UH	114	enum {
	115	READ_ALL,
	116	READ_TEMP,
	117	};
d375b3c3	118
ba6383f8	119	static gboolean checksum_valid(const struct rs_22_812_packet *rs_packet)
d375b3c3	120	{
ba6383f8	121	uint8_t *raw;
d375b3c3	122	uint8_t sum = 0;
ba6383f8 UH	123	int i;
	124
	125	raw = (void *)rs_packet;
	126
	127	for (i = 0; i < RS_22_812_PACKET_SIZE - 1; i++)
d375b3c3	128	sum += raw[i];
ba6383f8 UH	129
ba6383f8 UH	130	/* This is just a funky constant added to the checksum. */
d375b3c3	131	sum += 57;
ba6383f8 UH	132	sum -= rs_packet->checksum;
ba6383f8 UH	133	return (sum == 0);
d375b3c3 AG	134	}
d375b3c3 AG	135
ba6383f8	136	static gboolean selection_good(const struct rs_22_812_packet *rs_packet)
d375b3c3	137	{
ba6383f8	138	int count;
d375b3c3	139
d375b3c3	140	/* Does the packet have more than one multiplier ? */
ba6383f8	141	count = 0;
4e172b8f UH	142	count += (rs_packet->indicatrix1 & IND1_KILO) ? 1 : 0;
	143	count += (rs_packet->indicatrix1 & IND1_MEGA) ? 1 : 0;
	144	count += (rs_packet->indicatrix1 & IND1_MILI) ? 1 : 0;
	145	count += (rs_packet->indicatrix2 & IND2_MICRO) ? 1 : 0;
	146	count += (rs_packet->indicatrix2 & IND2_NANO) ? 1 : 0;
ba6383f8 UH	147	if (count > 1) {
ba6383f8 UH	148	sr_err("More than one multiplier detected in packet.");
d375b3c3	149	return FALSE;
ba6383f8	150	}
d375b3c3	151
ba6383f8 UH	152	/* Does the packet "measure" more than one type of value? */
ba6383f8 UH	153	count = 0;
4e172b8f UH	154	count += (rs_packet->indicatrix1 & IND1_HZ) ? 1 : 0;
	155	count += (rs_packet->indicatrix1 & IND1_OHM) ? 1 : 0;
	156	count += (rs_packet->indicatrix1 & IND1_FARAD) ? 1 : 0;
	157	count += (rs_packet->indicatrix1 & IND1_AMP) ? 1 : 0;
	158	count += (rs_packet->indicatrix1 & IND1_VOLT) ? 1 : 0;
	159	count += (rs_packet->indicatrix2 & IND2_DBM) ? 1 : 0;
	160	count += (rs_packet->indicatrix2 & IND2_SEC) ? 1 : 0;
	161	count += (rs_packet->indicatrix2 & IND2_DUTY) ? 1 : 0;
	162	count += (rs_packet->indicatrix2 & IND2_HFE) ? 1 : 0;
ba6383f8 UH	163	if (count > 1) {
ba6383f8 UH	164	sr_err("More than one measurement type detected in packet.");
d375b3c3	165	return FALSE;
ba6383f8	166	}
d375b3c3	167
d375b3c3 AG	168	return TRUE;
	169	}
	170
ba6383f8 UH	171	/*
ba6383f8 UH	172	* Since the 22-812 does not identify itself in any way, shape, or form,
d375b3c3 AG	173	* we really don't know for sure who is sending the data. We must use every
d375b3c3 AG	174	* possible check to filter out bad packets, especially since detection of the
ba6383f8 UH	175	* 22-812 depends on how well we can filter the packets.
	176	*/
	177	SR_PRIV gboolean rs_22_812_packet_valid(const struct rs_22_812_packet *rs_packet)
d375b3c3	178	{
2ecc5d43 AG	179	/*
	180	* Check for valid mode first, before calculating the checksum.
	181	* No point calculating the checksum, if we know we'll reject the packet
	182	* */
	183	if (!(rs_packet->mode < MODE_INVALID))
d375b3c3 AG	184	return FALSE;
d375b3c3 AG	185
90473587 AG	186	if (!checksum_valid(rs_packet)) {
90473587 AG	187	sr_spew("Packet with invalid checksum. Discarding.");
d375b3c3	188	return FALSE;
90473587	189	}
d375b3c3	190
90473587 AG	191	if (!selection_good(rs_packet)) {
90473587 AG	192	sr_spew("Packet with invalid selection bits. Discarding.");
d375b3c3	193	return FALSE;
90473587	194	}
ba6383f8	195
d375b3c3 AG	196	return TRUE;
	197	}
	198
ba6383f8	199	static uint8_t decode_digit(uint8_t raw_digit)
d375b3c3	200	{
ba6383f8	201	/* Take out the decimal point, so we can use a simple switch(). */
4e172b8f	202	raw_digit &= ~DP_MASK;
ba6383f8 UH	203
ba6383f8 UH	204	switch (raw_digit) {
d375b3c3	205	case 0x00:
4e172b8f	206	case LCD_0:
d375b3c3	207	return 0;
4e172b8f	208	case LCD_1:
d375b3c3	209	return 1;
4e172b8f	210	case LCD_2:
d375b3c3	211	return 2;
4e172b8f	212	case LCD_3:
d375b3c3	213	return 3;
4e172b8f	214	case LCD_4:
d375b3c3	215	return 4;
4e172b8f	216	case LCD_5:
d375b3c3	217	return 5;
4e172b8f	218	case LCD_6:
d375b3c3	219	return 6;
4e172b8f	220	case LCD_7:
d375b3c3	221	return 7;
4e172b8f	222	case LCD_8:
d375b3c3	223	return 8;
4e172b8f	224	case LCD_9:
d375b3c3 AG	225	return 9;
d375b3c3 AG	226	default:
ba6383f8	227	sr_err("Invalid digit byte: 0x%02x.", raw_digit);
d375b3c3 AG	228	return 0xff;
	229	}
	230	}
	231
4e172b8f	232	static double lcd_to_double(const struct rs_22_812_packet *rs_packet, int type)
d375b3c3	233	{
ba6383f8 UH	234	double rawval, multiplier = 1;
ba6383f8 UH	235	uint8_t digit, raw_digit;
d375b3c3 AG	236	gboolean dp_reached = FALSE;
d375b3c3 AG	237	int i, end;
ba6383f8 UH	238
	239	/* end = 1: Don't parse last digit. end = 0: Parse all digits. */
	240	end = (type == READ_TEMP) ? 1 : 0;
	241
	242	/* We have 4 digits, and we start from the most significant. */
	243	for (i = 3; i >= end; i--) {
	244	raw_digit = *(&(rs_packet->digit4) + i);
	245	digit = decode_digit(raw_digit);
	246	if (digit == 0xff) {
d375b3c3 AG	247	rawval = NAN;
	248	break;
	249	}
ba6383f8 UH	250	/*
	251	* Digit 1 does not have a decimal point. Instead, the decimal
	252	* point is used to indicate MAX, so we must avoid testing it.
	253	*/
4e172b8f	254	if ((i < 3) && (raw_digit & DP_MASK))
d375b3c3	255	dp_reached = TRUE;
ba6383f8 UH	256	if (dp_reached)
ba6383f8 UH	257	multiplier /= 10;
d375b3c3 AG	258	rawval = rawval * 10 + digit;
	259	}
	260	rawval *= multiplier;
4e172b8f	261	if (rs_packet->info & INFO_NEG)
d375b3c3 AG	262	rawval *= -1;
d375b3c3 AG	263
ba6383f8	264	/* See if we need to multiply our raw value by anything. */
4e172b8f	265	if (rs_packet->indicatrix1 & IND2_NANO) {
d375b3c3	266	rawval *= 1E-9;
4e172b8f	267	} else if (rs_packet->indicatrix2 & IND2_MICRO) {
d375b3c3	268	rawval *= 1E-6;
4e172b8f	269	} else if (rs_packet->indicatrix1 & IND1_MILI) {
d375b3c3	270	rawval *= 1E-3;
4e172b8f	271	} else if (rs_packet->indicatrix1 & IND1_KILO) {
d375b3c3	272	rawval *= 1E3;
4e172b8f	273	} else if (rs_packet->indicatrix1 & IND1_MEGA) {
d375b3c3 AG	274	rawval *= 1E6;
	275	}
	276
	277	return rawval;
	278	}
	279
ba6383f8	280	static gboolean is_celsius(struct rs_22_812_packet *rs_packet)
d375b3c3	281	{
4e172b8f	282	return ((rs_packet->digit4 & ~DP_MASK) == LCD_C);
d375b3c3 AG	283	}
d375b3c3 AG	284
ba6383f8	285	static gboolean is_shortcirc(struct rs_22_812_packet *rs_packet)
d375b3c3	286	{
4e172b8f	287	return ((rs_packet->digit2 & ~DP_MASK) == LCD_h);
d375b3c3 AG	288	}
d375b3c3 AG	289
ba6383f8	290	static gboolean is_logic_high(struct rs_22_812_packet *rs_packet)
7c41dc47	291	{
4e172b8f UH	292	sr_spew("Digit 2: 0x%02x.", rs_packet->digit2 & ~DP_MASK);
4e172b8f UH	293	return ((rs_packet->digit2 & ~DP_MASK) == LCD_H);
7c41dc47 AG	294	}
7c41dc47 AG	295
ba6383f8 UH	296	static void handle_packet(struct rs_22_812_packet *rs_packet,
ba6383f8 UH	297	struct dev_context *devc)
d375b3c3	298	{
ba6383f8	299	double rawval;
d375b3c3 AG	300	struct sr_datafeed_packet packet;
	301	struct sr_datafeed_analog *analog;
	302
4e172b8f	303	rawval = lcd_to_double(rs_packet, READ_ALL);
ba6383f8	304
886a52b6	305	/* TODO: Check malloc return value. */
d375b3c3 AG	306	analog = g_try_malloc0(sizeof(struct sr_datafeed_analog));
d375b3c3 AG	307	analog->num_samples = 1;
886a52b6	308	/* TODO: Check malloc return value. */
d375b3c3 AG	309	analog->data = g_try_malloc(sizeof(float));
	310	*analog->data = (float)rawval;
	311	analog->mq = -1;
	312
ba6383f8	313	switch (rs_packet->mode) {
4e172b8f	314	case MODE_DC_V:
d375b3c3 AG	315	analog->mq = SR_MQ_VOLTAGE;
	316	analog->unit = SR_UNIT_VOLT;
	317	analog->mqflags \|= SR_MQFLAG_DC;
	318	break;
4e172b8f	319	case MODE_AC_V:
d375b3c3 AG	320	analog->mq = SR_MQ_VOLTAGE;
	321	analog->unit = SR_UNIT_VOLT;
	322	analog->mqflags \|= SR_MQFLAG_AC;
	323	break;
4e172b8f UH	324	case MODE_DC_UA:
	325	case MODE_DC_MA:
	326	case MODE_DC_A:
d375b3c3 AG	327	analog->mq = SR_MQ_CURRENT;
	328	analog->unit = SR_UNIT_AMPERE;
	329	analog->mqflags \|= SR_MQFLAG_DC;
	330	break;
4e172b8f UH	331	case MODE_AC_UA:
	332	case MODE_AC_MA:
	333	case MODE_AC_A:
d375b3c3 AG	334	analog->mq = SR_MQ_CURRENT;
	335	analog->unit = SR_UNIT_AMPERE;
	336	analog->mqflags \|= SR_MQFLAG_AC;
	337	break;
4e172b8f	338	case MODE_OHM:
d375b3c3 AG	339	analog->mq = SR_MQ_RESISTANCE;
	340	analog->unit = SR_UNIT_OHM;
	341	break;
4e172b8f	342	case MODE_FARAD:
d375b3c3 AG	343	analog->mq = SR_MQ_CAPACITANCE;
	344	analog->unit = SR_UNIT_FARAD;
	345	break;
4e172b8f	346	case MODE_CONT:
d375b3c3 AG	347	analog->mq = SR_MQ_CONTINUITY;
d375b3c3 AG	348	analog->unit = SR_UNIT_BOOLEAN;
ba6383f8	349	*analog->data = is_shortcirc(rs_packet);
d375b3c3	350	break;
4e172b8f	351	case MODE_DIODE:
d375b3c3 AG	352	analog->mq = SR_MQ_VOLTAGE;
	353	analog->unit = SR_UNIT_VOLT;
	354	analog->mqflags \|= SR_MQFLAG_DIODE \| SR_MQFLAG_DC;
	355	break;
4e172b8f UH	356	case MODE_HZ:
	357	case MODE_VOLT_HZ:
	358	case MODE_AMP_HZ:
d375b3c3 AG	359	analog->mq = SR_MQ_FREQUENCY;
	360	analog->unit = SR_UNIT_HERTZ;
	361	break;
4e172b8f	362	case MODE_LOGIC:
ba6383f8 UH	363	/*
	364	* No matter whether or not we have an actual voltage reading,
	365	* we are measuring voltage, so we set our MQ as VOLTAGE.
	366	*/
7c41dc47	367	analog->mq = SR_MQ_VOLTAGE;
ba6383f8 UH	368	if (!isnan(rawval)) {
ba6383f8 UH	369	/* We have an actual voltage. */
7c41dc47 AG	370	analog->unit = SR_UNIT_VOLT;
7c41dc47 AG	371	} else {
ba6383f8	372	/* We have either HI or LOW. */
7c41dc47	373	analog->unit = SR_UNIT_BOOLEAN;
ba6383f8	374	*analog->data = is_logic_high(rs_packet);
7c41dc47	375	}
d375b3c3	376	break;
4e172b8f	377	case MODE_HFE:
d375b3c3 AG	378	analog->mq = SR_MQ_GAIN;
	379	analog->unit = SR_UNIT_UNITLESS;
	380	break;
4e172b8f UH	381	case MODE_DUTY:
	382	case MODE_VOLT_DUTY:
	383	case MODE_AMP_DUTY:
d375b3c3 AG	384	analog->mq = SR_MQ_DUTY_CYCLE;
	385	analog->unit = SR_UNIT_PERCENTAGE;
	386	break;
4e172b8f UH	387	case MODE_WIDTH:
	388	case MODE_VOLT_WIDTH:
	389	case MODE_AMP_WIDTH:
d375b3c3 AG	390	analog->mq = SR_MQ_PULSE_WIDTH;
d375b3c3 AG	391	analog->unit = SR_UNIT_SECOND;
4e172b8f	392	case MODE_TEMP:
d375b3c3	393	analog->mq = SR_MQ_TEMPERATURE;
ba6383f8	394	/* We need to reparse. */
4e172b8f	395	*analog->data = lcd_to_double(rs_packet, READ_TEMP);
ba6383f8 UH	396	analog->unit = is_celsius(rs_packet) ?
ba6383f8 UH	397	SR_UNIT_CELSIUS : SR_UNIT_FAHRENHEIT;
d375b3c3	398	break;
4e172b8f	399	case MODE_DBM:
d375b3c3 AG	400	analog->mq = SR_MQ_POWER;
	401	analog->unit = SR_UNIT_DECIBEL_MW;
	402	analog->mqflags \|= SR_MQFLAG_AC;
	403	break;
	404	default:
ba6383f8	405	sr_err("Unknown mode: %d.", rs_packet->mode);
d375b3c3 AG	406	break;
	407	}
	408
4e172b8f	409	if (rs_packet->info & INFO_HOLD)
d375b3c3	410	analog->mqflags \|= SR_MQFLAG_HOLD;
4e172b8f	411	if (rs_packet->digit4 & DIG4_MAX)
d375b3c3	412	analog->mqflags \|= SR_MQFLAG_MAX;
4e172b8f	413	if (rs_packet->indicatrix2 & IND2_MIN)
d375b3c3	414	analog->mqflags \|= SR_MQFLAG_MIN;
4e172b8f	415	if (rs_packet->info & INFO_AUTO)
d375b3c3	416	analog->mqflags \|= SR_MQFLAG_AUTORANGE;
d375b3c3 AG	417
	418	if (analog->mq != -1) {
	419	/* Got a measurement. */
dccbd0ed	420	sr_spew("Value: %f.", rawval);
d375b3c3 AG	421	packet.type = SR_DF_ANALOG;
	422	packet.payload = analog;
	423	sr_session_send(devc->cb_data, &packet);
	424	devc->num_samples++;
	425	}
	426	g_free(analog->data);
	427	g_free(analog);
	428	}
	429
401476da	430	static void handle_new_data(struct dev_context *devc)
d375b3c3 AG	431	{
d375b3c3 AG	432	int len;
ba6383f8 UH	433	size_t i, offset = 0;
	434	struct rs_22_812_packet *rs_packet;
	435
	436	/* Try to get as much data as the buffer can hold. */
d375b3c3	437	len = RS_DMM_BUFSIZE - devc->buflen;
401476da	438	len = serial_read(devc->serial, devc->buf + devc->buflen, len);
d375b3c3	439	if (len < 1) {
ba6383f8	440	sr_err("Serial port read error.");
d375b3c3 AG	441	return;
	442	}
	443	devc->buflen += len;
	444
ba6383f8 UH	445	/* Now look for packets in that data. */
	446	while ((devc->buflen - offset) >= RS_22_812_PACKET_SIZE) {
	447	rs_packet = (void *)(devc->buf + offset);
	448	if (rs_22_812_packet_valid(rs_packet)) {
	449	handle_packet(rs_packet, devc);
d375b3c3 AG	450	offset += RS_22_812_PACKET_SIZE;
	451	} else {
	452	offset++;
	453	}
	454	}
	455
ba6383f8 UH	456	/* If we have any data left, move it to the beginning of our buffer. */
ba6383f8 UH	457	for (i = 0; i < devc->buflen - offset; i++)
d375b3c3 AG	458	devc->buf[i] = devc->buf[offset + i];
	459	devc->buflen -= offset;
	460	}
	461
ba6383f8	462	SR_PRIV int radioshack_dmm_receive_data(int fd, int revents, void *cb_data)
d375b3c3	463	{
642e9d62	464	struct sr_dev_inst *sdi;
d375b3c3 AG	465	struct dev_context *devc;
d375b3c3 AG	466
401476da BV	467	(void)fd;
401476da BV	468
d375b3c3 AG	469	if (!(sdi = cb_data))
	470	return TRUE;
	471
	472	if (!(devc = sdi->priv))
	473	return TRUE;
	474
ba6383f8	475	if (revents == G_IO_IN) {
d375b3c3	476	/* Serial data arrived. */
401476da	477	handle_new_data(devc);
d375b3c3 AG	478	}
	479
	480	if (devc->num_samples >= devc->limit_samples) {
	481	sdi->driver->dev_acquisition_stop(sdi, cb_data);
	482	return TRUE;
	483	}
	484
	485	return TRUE;
	486	}