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