[libsigrok.git] / src / hardware / brymen-dmm / parser.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/>.
 */

#include <config.h>
#include "protocol.h"

#define MAX_PACKET_LEN 22

/* Flags passed from the DMM. */
struct brymen_flags {
	gboolean is_low_batt, is_decibel, is_duty_cycle, is_hertz, is_amp;
	gboolean is_beep, is_ohm, is_fahrenheit, is_celsius, is_capacitance;
	gboolean is_diode, is_volt, is_dc, is_ac;
};

struct bm850_command {
	uint8_t dle;
	uint8_t stx;
	uint8_t cmd;
	uint8_t arg[2];
	uint8_t checksum;
	uint8_t dle2;
	uint8_t etx;
};

struct brymen_header {
	uint8_t dle;
	uint8_t stx;
	uint8_t cmd;
	uint8_t len;
};

struct brymen_tail {
	uint8_t checksum;
	uint8_t dle;
	uint8_t etx;
};

/*
 * We only have one command because we only support the BM-857. However, the
 * driver is easily extensible to support more models, as the protocols are
 * very similar.
 */
enum {
	BM_CMD_REQUEST_READING = 0x00,
};

static int bm_send_command(uint8_t command, uint8_t arg1, uint8_t arg2,
			   struct sr_serial_dev_inst *serial)
{
	struct bm850_command cmdout;
	int written;

	cmdout.dle = 0x10;
	cmdout.stx = 0x02;
	cmdout.cmd = command;
	cmdout.arg[0] = arg1;
	cmdout.arg[1] = arg2;
	cmdout.checksum = arg1 ^ arg2;
	cmdout.dle2 = 0x10;
	cmdout.etx = 0x03;

	/* TODO: How to compute the checksum? Hardware seems to ignore it. */

	/* Request reading. */
	written = serial_write_blocking(serial, &cmdout, sizeof(cmdout),
			serial_timeout(serial, sizeof(cmdout)));
	if (written != sizeof(cmdout))
		return SR_ERR;

	return SR_OK;
}

SR_PRIV int brymen_packet_request(struct sr_serial_dev_inst *serial)
{
	return bm_send_command(BM_CMD_REQUEST_READING, 0, 0, serial);
}

SR_PRIV int brymen_packet_length(const uint8_t *buf, int *len)
{
	struct brymen_header *hdr;
	int packet_len;
	size_t buflen;

	buflen = *len;
	hdr = (void *)buf;

	/* Did we receive a complete header yet? */
	if (buflen < sizeof(*hdr))
		return PACKET_NEED_MORE_DATA;

	if (hdr->dle != 0x10 || hdr->stx != 0x02)
		return PACKET_INVALID_HEADER;

	/* Our packet includes the header, the payload, and the tail. */
	packet_len = sizeof(*hdr) + hdr->len + sizeof(struct brymen_tail);

	/* In case we pick up an invalid header, limit our search. */
	if (packet_len > MAX_PACKET_LEN) {
		sr_spew("Header specifies an invalid payload length: %i.",
			hdr->len);
		return PACKET_INVALID_HEADER;
	}

	*len = packet_len;
	sr_spew("Expecting a %d-byte packet.", *len);
	return PACKET_HEADER_OK;
}

SR_PRIV gboolean brymen_packet_is_valid(const uint8_t *buf)
{
	struct brymen_header *hdr;
	struct brymen_tail *tail;
	int i;
	uint8_t chksum = 0;
	uint8_t *payload;

	payload = (uint8_t *)(buf + sizeof(struct brymen_header));

	hdr = (void *)buf;
	tail = (void *)(payload + hdr->len);

	for (i = 0; i< hdr->len; i++)
		chksum ^= payload[i];

	if (tail->checksum != chksum) {
		sr_dbg("Packet has invalid checksum 0x%.2x. Expected 0x%.2x.",
		       chksum, tail->checksum);
		return FALSE;
	}

	return TRUE;
}

static int parse_value(const char *strbuf, int len, float *floatval)
{
	int s, d;
	char str[32];

	if (strstr(strbuf, "OL")) {
		sr_dbg("Overlimit.");
		*floatval = INFINITY;
		return SR_OK;
	}

	memset(str, 0, sizeof(str));
	/* Spaces may interfere with parsing the exponent. Strip them. */
	for (s = 0, d = 0; s < len; s++) {
		if (strbuf[s] != ' ')
			str[d++] = strbuf[s];
	}
	if (sr_atof_ascii(str, floatval) != SR_OK)
		return SR_ERR;

	return SR_OK;
}

static void parse_flags(const uint8_t *buf, struct brymen_flags *info)
{
	info->is_low_batt	= (buf[4 + 3] & (1 << 7)) != 0;

	info->is_decibel	= (buf[4 + 1] & (1 << 5)) != 0;
	info->is_duty_cycle	= (buf[4 + 1] & (1 << 3)) != 0;
	info->is_hertz		= (buf[4 + 1] & (1 << 2)) != 0;
	info->is_amp		= (buf[4 + 1] & (1 << 1)) != 0;
	info->is_beep		= (buf[4 + 1] & (1 << 0)) != 0;

	info->is_ohm		= (buf[4 + 0] & (1 << 7)) != 0;
	info->is_fahrenheit	= (buf[4 + 0] & (1 << 6)) != 0;
	info->is_celsius	= (buf[4 + 0] & (1 << 5)) != 0;
	info->is_diode		= (buf[4 + 0] & (1 << 4)) != 0;
	info->is_capacitance	= (buf[4 + 0] & (1 << 3)) != 0;
	info->is_volt		= (buf[4 + 0] & (1 << 2)) != 0;
	info->is_dc		= (buf[4 + 0] & (1 << 1)) != 0;
	info->is_ac		= (buf[4 + 0] & (1 << 0)) != 0;
}

SR_PRIV int brymen_parse(const uint8_t *buf, float *floatval,
		struct sr_datafeed_analog *analog, void *info)
{
	struct brymen_flags flags;
	struct brymen_header *hdr;
	uint8_t *bfunc;
	int asciilen;

	(void)info;

	hdr = (void *)buf;
	bfunc = (uint8_t *)(buf + sizeof(struct brymen_header));

	analog->meaning->mqflags = 0;

	/* Give some debug info about the package. */
	asciilen = hdr->len - 4;
	sr_dbg("DMM flags: %.2x %.2x %.2x %.2x",
	       bfunc[3], bfunc[2], bfunc[1], bfunc[0]);
	/* Value is an ASCII string. */
	sr_dbg("DMM packet: \"%.*s\"", asciilen, bfunc + 4);

	parse_flags(buf, &flags);
	if (parse_value((const char *)(bfunc + 4), asciilen, floatval) != SR_OK)
		return SR_ERR;

	if (flags.is_volt) {
		analog->meaning->mq = SR_MQ_VOLTAGE;
		analog->meaning->unit = SR_UNIT_VOLT;
	}
	if (flags.is_amp) {
		analog->meaning->mq = SR_MQ_CURRENT;
		analog->meaning->unit = SR_UNIT_AMPERE;
	}
	if (flags.is_ohm) {
		if (flags.is_beep)
			analog->meaning->mq = SR_MQ_CONTINUITY;
		else
			analog->meaning->mq = SR_MQ_RESISTANCE;
		analog->meaning->unit = SR_UNIT_OHM;
	}
	if (flags.is_hertz) {
		analog->meaning->mq = SR_MQ_FREQUENCY;
		analog->meaning->unit = SR_UNIT_HERTZ;
	}
	if (flags.is_duty_cycle) {
		analog->meaning->mq = SR_MQ_DUTY_CYCLE;
		analog->meaning->unit = SR_UNIT_PERCENTAGE;
	}
	if (flags.is_capacitance) {
		analog->meaning->mq = SR_MQ_CAPACITANCE;
		analog->meaning->unit = SR_UNIT_FARAD;
	}
	if (flags.is_fahrenheit) {
		analog->meaning->mq = SR_MQ_TEMPERATURE;
		analog->meaning->unit = SR_UNIT_FAHRENHEIT;
	}
	if (flags.is_celsius) {
		analog->meaning->mq = SR_MQ_TEMPERATURE;
		analog->meaning->unit = SR_UNIT_CELSIUS;
	}
	if (flags.is_capacitance) {
		analog->meaning->mq = SR_MQ_CAPACITANCE;
		analog->meaning->unit = SR_UNIT_FARAD;
	}

	/*
	 * The high-end Brymen models have a configurable reference impedance.
	 * When the reference impedance is changed, the DMM sends one packet
	 * with the value of the new reference impedance. Both decibel and ohm
	 * flags are set in this case, so we must be careful to correctly
	 * identify the value as ohm, not dBmW.
	 */
	if (flags.is_decibel && !flags.is_ohm) {
		analog->meaning->mq = SR_MQ_POWER;
		analog->meaning->unit = SR_UNIT_DECIBEL_MW;
		/*
		 * For some reason, dBm measurements are sent by the multimeter
		 * with a value three orders of magnitude smaller than the
		 * displayed value.
		 */
		*floatval *= 1000;
	}

	if (flags.is_diode)
		analog->meaning->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
	/* We can have both AC+DC in a single measurement. */
	if (flags.is_ac)
		analog->meaning->mqflags |= SR_MQFLAG_AC;
	if (flags.is_dc)
		analog->meaning->mqflags |= SR_MQFLAG_DC;

	if (flags.is_low_batt)
		sr_warn("Low battery!");

	return SR_OK;
}
Commit	Line	Data
601fb67c	1	/*
c5d6f5cc	2	* This file is part of the libsigrok project.
601fb67c 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
6ec6c43b	20	#include <config.h>
601fb67c	21	#include "protocol.h"
601fb67c	22
c5d6f5cc UH	23	#define MAX_PACKET_LEN 22
	24
	25	/* Flags passed from the DMM. */
601fb67c	26	struct brymen_flags {
c5d6f5cc UH	27	gboolean is_low_batt, is_decibel, is_duty_cycle, is_hertz, is_amp;
	28	gboolean is_beep, is_ohm, is_fahrenheit, is_celsius, is_capacitance;
	29	gboolean is_diode, is_volt, is_dc, is_ac;
601fb67c AG	30	};
	31
	32	struct bm850_command {
	33	uint8_t dle;
	34	uint8_t stx;
	35	uint8_t cmd;
	36	uint8_t arg[2];
	37	uint8_t checksum;
	38	uint8_t dle2;
	39	uint8_t etx;
	40	};
	41
	42	struct brymen_header {
	43	uint8_t dle;
	44	uint8_t stx;
	45	uint8_t cmd;
	46	uint8_t len;
	47	};
	48
	49	struct brymen_tail {
	50	uint8_t checksum;
	51	uint8_t dle;
	52	uint8_t etx;
	53	};
	54
	55	/*
	56	* We only have one command because we only support the BM-857. However, the
c5d6f5cc UH	57	* driver is easily extensible to support more models, as the protocols are
c5d6f5cc UH	58	* very similar.
601fb67c AG	59	*/
	60	enum {
	61	BM_CMD_REQUEST_READING = 0x00,
	62	};
	63
601fb67c AG	64	static int bm_send_command(uint8_t command, uint8_t arg1, uint8_t arg2,
	65	struct sr_serial_dev_inst *serial)
	66	{
c5d6f5cc UH	67	struct bm850_command cmdout;
	68	int written;
	69
	70	cmdout.dle = 0x10;
	71	cmdout.stx = 0x02;
	72	cmdout.cmd = command;
	73	cmdout.arg[0] = arg1;
	74	cmdout.arg[1] = arg2;
	75	cmdout.checksum = arg1 ^ arg2;
	76	cmdout.dle2 = 0x10;
	77	cmdout.etx = 0x03;
	78
	79	/* TODO: How to compute the checksum? Hardware seems to ignore it. */
	80
	81	/* Request reading. */
b9ed8eab UH	82	written = serial_write_blocking(serial, &cmdout, sizeof(cmdout),
b9ed8eab UH	83	serial_timeout(serial, sizeof(cmdout)));
c5d6f5cc UH	84	if (written != sizeof(cmdout))
	85	return SR_ERR;
	86
	87	return SR_OK;
601fb67c AG	88	}
	89
	90	SR_PRIV int brymen_packet_request(struct sr_serial_dev_inst *serial)
	91	{
	92	return bm_send_command(BM_CMD_REQUEST_READING, 0, 0, serial);
	93	}
	94
	95	SR_PRIV int brymen_packet_length(const uint8_t buf, int len)
	96	{
	97	struct brymen_header *hdr;
601fb67c	98	int packet_len;
c5d6f5cc UH	99	size_t buflen;
	100
	101	buflen = *len;
	102	hdr = (void *)buf;
	103
601fb67c	104	/* Did we receive a complete header yet? */
c5d6f5cc	105	if (buflen < sizeof(*hdr))
601fb67c	106	return PACKET_NEED_MORE_DATA;
c5d6f5cc	107
601fb67c AG	108	if (hdr->dle != 0x10 \|\| hdr->stx != 0x02)
601fb67c AG	109	return PACKET_INVALID_HEADER;
c5d6f5cc UH	110
c5d6f5cc UH	111	/* Our packet includes the header, the payload, and the tail. */
601fb67c	112	packet_len = sizeof(*hdr) + hdr->len + sizeof(struct brymen_tail);
c5d6f5cc UH	113
	114	/* In case we pick up an invalid header, limit our search. */
	115	if (packet_len > MAX_PACKET_LEN) {
601fb67c AG	116	sr_spew("Header specifies an invalid payload length: %i.",
	117	hdr->len);
	118	return PACKET_INVALID_HEADER;
	119	}
c5d6f5cc	120
601fb67c AG	121	*len = packet_len;
	122	sr_spew("Expecting a %d-byte packet.", *len);
	123	return PACKET_HEADER_OK;
	124	}
	125
	126	SR_PRIV gboolean brymen_packet_is_valid(const uint8_t *buf)
	127	{
	128	struct brymen_header *hdr;
	129	struct brymen_tail *tail;
	130	int i;
	131	uint8_t chksum = 0;
c5d6f5cc	132	uint8_t *payload;
176d785d	133
c5d6f5cc UH	134	payload = (uint8_t *)(buf + sizeof(struct brymen_header));
	135
	136	hdr = (void *)buf;
	137	tail = (void *)(payload + hdr->len);
176d785d	138
601fb67c AG	139	for (i = 0; i< hdr->len; i++)
601fb67c AG	140	chksum ^= payload[i];
176d785d	141
601fb67c	142	if (tail->checksum != chksum) {
c5d6f5cc	143	sr_dbg("Packet has invalid checksum 0x%.2x. Expected 0x%.2x.",
601fb67c AG	144	chksum, tail->checksum);
	145	return FALSE;
	146	}
176d785d	147
601fb67c AG	148	return TRUE;
	149	}
	150
c5d6f5cc	151	static int parse_value(const char strbuf, int len, float floatval)
601fb67c AG	152	{
	153	int s, d;
	154	char str[32];
	155
	156	if (strstr(strbuf, "OL")) {
	157	sr_dbg("Overlimit.");
	158	*floatval = INFINITY;
	159	return SR_OK;
	160	}
	161
	162	memset(str, 0, sizeof(str));
933e63a1 BV	163	/* Spaces may interfere with parsing the exponent. Strip them. */
933e63a1 BV	164	for (s = 0, d = 0; s < len; s++) {
601fb67c AG	165	if (strbuf[s] != ' ')
601fb67c AG	166	str[d++] = strbuf[s];
933e63a1 BV	167	}
	168	if (sr_atof_ascii(str, floatval) != SR_OK)
	169	return SR_ERR;
601fb67c AG	170
	171	return SR_OK;
	172	}
c5d6f5cc	173
601fb67c AG	174	static void parse_flags(const uint8_t buf, struct brymen_flags info)
601fb67c AG	175	{
c5d6f5cc UH	176	info->is_low_batt = (buf[4 + 3] & (1 << 7)) != 0;
	177
	178	info->is_decibel = (buf[4 + 1] & (1 << 5)) != 0;
	179	info->is_duty_cycle = (buf[4 + 1] & (1 << 3)) != 0;
	180	info->is_hertz = (buf[4 + 1] & (1 << 2)) != 0;
	181	info->is_amp = (buf[4 + 1] & (1 << 1)) != 0;
	182	info->is_beep = (buf[4 + 1] & (1 << 0)) != 0;
	183
	184	info->is_ohm = (buf[4 + 0] & (1 << 7)) != 0;
	185	info->is_fahrenheit = (buf[4 + 0] & (1 << 6)) != 0;
	186	info->is_celsius = (buf[4 + 0] & (1 << 5)) != 0;
	187	info->is_diode = (buf[4 + 0] & (1 << 4)) != 0;
	188	info->is_capacitance = (buf[4 + 0] & (1 << 3)) != 0;
	189	info->is_volt = (buf[4 + 0] & (1 << 2)) != 0;
	190	info->is_dc = (buf[4 + 0] & (1 << 1)) != 0;
	191	info->is_ac = (buf[4 + 0] & (1 << 0)) != 0;
601fb67c AG	192	}
601fb67c AG	193
933e63a1	194	SR_PRIV int brymen_parse(const uint8_t buf, float floatval,
1653c430	195	struct sr_datafeed_analog analog, void info)
601fb67c AG	196	{
601fb67c AG	197	struct brymen_flags flags;
c5d6f5cc UH	198	struct brymen_header *hdr;
c5d6f5cc UH	199	uint8_t *bfunc;
601fb67c AG	200	int asciilen;
	201
	202	(void)info;
c5d6f5cc UH	203
	204	hdr = (void *)buf;
	205	bfunc = (uint8_t *)(buf + sizeof(struct brymen_header));
	206
1653c430	207	analog->meaning->mqflags = 0;
601fb67c	208
c5d6f5cc	209	/* Give some debug info about the package. */
601fb67c AG	210	asciilen = hdr->len - 4;
	211	sr_dbg("DMM flags: %.2x %.2x %.2x %.2x",
	212	bfunc[3], bfunc[2], bfunc[1], bfunc[0]);
c5d6f5cc	213	/* Value is an ASCII string. */
601fb67c AG	214	sr_dbg("DMM packet: \"%.*s\"", asciilen, bfunc + 4);
	215
	216	parse_flags(buf, &flags);
933e63a1 BV	217	if (parse_value((const char *)(bfunc + 4), asciilen, floatval) != SR_OK)
933e63a1 BV	218	return SR_ERR;
601fb67c	219
c5d6f5cc	220	if (flags.is_volt) {
1653c430 UH	221	analog->meaning->mq = SR_MQ_VOLTAGE;
1653c430 UH	222	analog->meaning->unit = SR_UNIT_VOLT;
601fb67c	223	}
c5d6f5cc	224	if (flags.is_amp) {
1653c430 UH	225	analog->meaning->mq = SR_MQ_CURRENT;
1653c430 UH	226	analog->meaning->unit = SR_UNIT_AMPERE;
601fb67c	227	}
c5d6f5cc UH	228	if (flags.is_ohm) {
c5d6f5cc UH	229	if (flags.is_beep)
1653c430	230	analog->meaning->mq = SR_MQ_CONTINUITY;
601fb67c	231	else
1653c430 UH	232	analog->meaning->mq = SR_MQ_RESISTANCE;
1653c430 UH	233	analog->meaning->unit = SR_UNIT_OHM;
601fb67c	234	}
c5d6f5cc	235	if (flags.is_hertz) {
1653c430 UH	236	analog->meaning->mq = SR_MQ_FREQUENCY;
1653c430 UH	237	analog->meaning->unit = SR_UNIT_HERTZ;
601fb67c	238	}
c5d6f5cc	239	if (flags.is_duty_cycle) {
1653c430 UH	240	analog->meaning->mq = SR_MQ_DUTY_CYCLE;
1653c430 UH	241	analog->meaning->unit = SR_UNIT_PERCENTAGE;
601fb67c	242	}
c5d6f5cc	243	if (flags.is_capacitance) {
1653c430 UH	244	analog->meaning->mq = SR_MQ_CAPACITANCE;
1653c430 UH	245	analog->meaning->unit = SR_UNIT_FARAD;
601fb67c	246	}
c5d6f5cc	247	if (flags.is_fahrenheit) {
1653c430 UH	248	analog->meaning->mq = SR_MQ_TEMPERATURE;
1653c430 UH	249	analog->meaning->unit = SR_UNIT_FAHRENHEIT;
601fb67c	250	}
c5d6f5cc	251	if (flags.is_celsius) {
1653c430 UH	252	analog->meaning->mq = SR_MQ_TEMPERATURE;
1653c430 UH	253	analog->meaning->unit = SR_UNIT_CELSIUS;
601fb67c	254	}
c5d6f5cc	255	if (flags.is_capacitance) {
1653c430 UH	256	analog->meaning->mq = SR_MQ_CAPACITANCE;
1653c430 UH	257	analog->meaning->unit = SR_UNIT_FARAD;
601fb67c	258	}
c5d6f5cc	259
601fb67c	260	/*
c5d6f5cc	261	* The high-end Brymen models have a configurable reference impedance.
601fb67c AG	262	* When the reference impedance is changed, the DMM sends one packet
	263	* with the value of the new reference impedance. Both decibel and ohm
	264	* flags are set in this case, so we must be careful to correctly
c5d6f5cc	265	* identify the value as ohm, not dBmW.
601fb67c	266	*/
c5d6f5cc	267	if (flags.is_decibel && !flags.is_ohm) {
1653c430 UH	268	analog->meaning->mq = SR_MQ_POWER;
1653c430 UH	269	analog->meaning->unit = SR_UNIT_DECIBEL_MW;
601fb67c AG	270	/*
	271	* For some reason, dBm measurements are sent by the multimeter
	272	* with a value three orders of magnitude smaller than the
	273	* displayed value.
c5d6f5cc	274	*/
601fb67c AG	275	floatval = 1000;
	276	}
	277
c5d6f5cc	278	if (flags.is_diode)
64aa214a	279	analog->meaning->mqflags \|= SR_MQFLAG_DIODE \| SR_MQFLAG_DC;
c5d6f5cc UH	280	/* We can have both AC+DC in a single measurement. */
c5d6f5cc UH	281	if (flags.is_ac)
1653c430	282	analog->meaning->mqflags \|= SR_MQFLAG_AC;
c5d6f5cc	283	if (flags.is_dc)
1653c430	284	analog->meaning->mqflags \|= SR_MQFLAG_DC;
601fb67c	285
c5d6f5cc	286	if (flags.is_low_batt)
11addc89	287	sr_warn("Low battery!");
601fb67c AG	288
601fb67c AG	289	return SR_OK;
c5d6f5cc	290	}