[libsigrok.git] / 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 "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(serial, &cmdout, 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->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->mq = SR_MQ_VOLTAGE;
		analog->unit = SR_UNIT_VOLT;
	}
	if (flags.is_amp) {
		analog->mq = SR_MQ_CURRENT;
		analog->unit = SR_UNIT_AMPERE;
	}
	if (flags.is_ohm) {
		if (flags.is_beep)
			analog->mq = SR_MQ_CONTINUITY;
		else
			analog->mq = SR_MQ_RESISTANCE;
		analog->unit = SR_UNIT_OHM;
	}
	if (flags.is_hertz) {
		analog->mq = SR_MQ_FREQUENCY;
		analog->unit = SR_UNIT_HERTZ;
	}
	if (flags.is_duty_cycle) {
		analog->mq = SR_MQ_DUTY_CYCLE;
		analog->unit = SR_UNIT_PERCENTAGE;
	}
	if (flags.is_capacitance) {
		analog->mq = SR_MQ_CAPACITANCE;
		analog->unit = SR_UNIT_FARAD;
	}
	if (flags.is_fahrenheit) {
		analog->mq = SR_MQ_TEMPERATURE;
		analog->unit = SR_UNIT_FAHRENHEIT;
	}
	if (flags.is_celsius) {
		analog->mq = SR_MQ_TEMPERATURE;
		analog->unit = SR_UNIT_CELSIUS;
	}
	if (flags.is_capacitance) {
		analog->mq = SR_MQ_CAPACITANCE;
		analog->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->mq = SR_MQ_POWER;
		analog->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->mqflags |= SR_MQFLAG_DIODE;
	/* We can have both AC+DC in a single measurement. */
	if (flags.is_ac)
		analog->mqflags |= SR_MQFLAG_AC;
	if (flags.is_dc)
		analog->mqflags |= SR_MQFLAG_DC;

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

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