[libsigrok.git] / src / hardware / hp-3478a / protocol.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2017-2018 Frank Stettner <frank-stettner@gmx.net>
 *
 * 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 <math.h>
#include <stdlib.h>
#include "scpi.h"
#include "protocol.h"

static int set_mq_volt(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);
static int set_mq_amp(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);
static int set_mq_ohm(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);

static const struct {
	enum sr_mq mq;
	int (*set_mode)(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);
} sr_mq_to_cmd_map[] = {
	{ SR_MQ_VOLTAGE, set_mq_volt },
	{ SR_MQ_CURRENT, set_mq_amp },
	{ SR_MQ_RESISTANCE, set_mq_ohm },
};

static int set_mq_volt(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags)
{
	if ((flags & SR_MQFLAG_AC) != SR_MQFLAG_AC &&
		(flags & SR_MQFLAG_DC) != SR_MQFLAG_DC)
		return SR_ERR_NA;

	return sr_scpi_send(scpi, "%s",
		((flags & SR_MQFLAG_AC) == SR_MQFLAG_AC) ? "F2" : "F1");
}

static int set_mq_amp(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags)
{
	if ((flags & SR_MQFLAG_AC) != SR_MQFLAG_AC &&
		(flags & SR_MQFLAG_DC) != SR_MQFLAG_DC)
		return SR_ERR_NA;

	return sr_scpi_send(scpi, "%s", (flags & SR_MQFLAG_AC) ? "F6" : "F5");
}

static int set_mq_ohm(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags)
{
	return sr_scpi_send(scpi, "%s",
		(flags & SR_MQFLAG_FOUR_WIRE) ? "F4" : "F3");
}

SR_PRIV int hp_3478a_set_mq(const struct sr_dev_inst *sdi, enum sr_mq mq,
				enum sr_mqflag mq_flags)
{
	int ret;
	size_t i;
	struct sr_scpi_dev_inst *scpi = sdi->conn;
	struct dev_context *devc = sdi->priv;

	/* No need to send command if we're not changing measurement type. */
	if (devc->measurement_mq == mq &&
		((devc->measurement_mq_flags & mq_flags) == mq_flags))
		return SR_OK;

	for (i = 0; i < ARRAY_SIZE(sr_mq_to_cmd_map); i++) {
		if (sr_mq_to_cmd_map[i].mq != mq)
			continue;

		ret = sr_mq_to_cmd_map[i].set_mode(scpi, mq_flags);
		if (ret != SR_OK)
			return ret;

		ret = hp_3478a_get_status_bytes(sdi);
		return ret;
	}

	return SR_ERR_NA;
}

SR_PRIV int hp_3478a_set_range(const struct sr_dev_inst *sdi, int range_exp)
{
	int ret;
	struct sr_scpi_dev_inst *scpi = sdi->conn;
	struct dev_context *devc = sdi->priv;

	/* No need to send command if we're not changing the range. */
	if (devc->range_exp == range_exp)
		return SR_OK;

	/* -99 is a dummy exponent for auto ranging. */
	if (range_exp == -99)
		ret = sr_scpi_send(scpi, "RA");
	else
		ret = sr_scpi_send(scpi, "R%i", range_exp);
	if (ret != SR_OK)
		return ret;

	return hp_3478a_get_status_bytes(sdi);
}

SR_PRIV int hp_3478a_set_digits(const struct sr_dev_inst *sdi, uint8_t digits)
{
	int ret;
	struct sr_scpi_dev_inst *scpi = sdi->conn;
	struct dev_context *devc = sdi->priv;

	/* No need to send command if we're not changing the range. */
	if (devc->spec_digits == digits)
		return SR_OK;

	/* digits are based on devc->spec_digits, so we have to substract 1 */
	ret = sr_scpi_send(scpi, "N%i", digits-1);
	if (ret != SR_OK)
		return ret;

	return hp_3478a_get_status_bytes(sdi);
}

static int parse_range_vdc(struct dev_context *devc, uint8_t range_byte)
{
	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30MV) {
		devc->range_exp = -2;
		devc->enc_digits = devc->spec_digits - 2;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300MV) {
		devc->range_exp = -1;
		devc->enc_digits = devc->spec_digits - 3;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_3V) {
		devc->range_exp = 0;
		devc->enc_digits = devc->spec_digits - 1;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30V) {
		devc->range_exp = 1;
		devc->enc_digits = devc->spec_digits - 2;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300V) {
		devc->range_exp = 2;
		devc->enc_digits = devc->spec_digits - 3;
	} else
		return SR_ERR_DATA;

	return SR_OK;
}

static int parse_range_vac(struct dev_context *devc, uint8_t range_byte)
{
	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300MV) {
		devc->range_exp = -1;
		devc->enc_digits = devc->spec_digits - 3;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_3V) {
		devc->range_exp = 0;
		devc->enc_digits = devc->spec_digits - 1;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_30V) {
		devc->range_exp = 1;
		devc->enc_digits = devc->spec_digits - 2;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300V) {
		devc->range_exp = 2;
		devc->enc_digits = devc->spec_digits - 3;
	} else
		return SR_ERR_DATA;

	return SR_OK;
}

static int parse_range_a(struct dev_context *devc, uint8_t range_byte)
{
	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_300MA) {
		devc->range_exp = -1;
		devc->enc_digits = devc->spec_digits - 3;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_3A) {
		devc->range_exp = 0;
		devc->enc_digits = devc->spec_digits - 1;
	} else
		return SR_ERR_DATA;

	return SR_OK;
}

static int parse_range_ohm(struct dev_context *devc, uint8_t range_byte)
{
	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30R) {
		devc->range_exp = 1;
		devc->enc_digits = devc->spec_digits - 2;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300R) {
		devc->range_exp = 2;
		devc->enc_digits = devc->spec_digits - 3;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3KR) {
		devc->range_exp = 3;
		devc->enc_digits = devc->spec_digits - 1;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30KR) {
		devc->range_exp = 4;
		devc->enc_digits = devc->spec_digits - 2;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300KR) {
		devc->range_exp = 5;
		devc->enc_digits = devc->spec_digits - 3;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3MR) {
		devc->range_exp = 6;
		devc->enc_digits = devc->spec_digits - 1;
	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30MR) {
		devc->range_exp = 7;
		devc->enc_digits = devc->spec_digits - 2;
	} else
		return SR_ERR_DATA;

	return SR_OK;
}

static int parse_function_byte(struct dev_context *devc, uint8_t function_byte)
{
	/* Digits / Resolution (spec_digits must be set before range parsing) */
	if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_5_5)
		devc->spec_digits = 6;
	else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_4_5)
		devc->spec_digits = 5;
	else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_3_5)
		devc->spec_digits = 4;
	else
		return SR_ERR_DATA;

	/* Function + Range */
	devc->measurement_mq_flags = 0;
	devc->acquisition_mq_flags = 0;
	if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_VDC) {
		devc->measurement_mq = SR_MQ_VOLTAGE;
		devc->measurement_mq_flags |= SR_MQFLAG_DC;
		devc->acquisition_mq_flags |= SR_MQFLAG_DC;
		devc->measurement_unit = SR_UNIT_VOLT;
		parse_range_vdc(devc, function_byte);
	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_VAC) {
		devc->measurement_mq = SR_MQ_VOLTAGE;
		devc->measurement_mq_flags |= SR_MQFLAG_AC;
		devc->acquisition_mq_flags |= SR_MQFLAG_AC | SR_MQFLAG_RMS;
		devc->measurement_unit = SR_UNIT_VOLT;
		parse_range_vac(devc, function_byte);
	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_2WR) {
		devc->measurement_mq = SR_MQ_RESISTANCE;
		devc->measurement_unit = SR_UNIT_OHM;
		parse_range_ohm(devc, function_byte);
	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_4WR) {
		devc->measurement_mq = SR_MQ_RESISTANCE;
		devc->measurement_mq_flags |= SR_MQFLAG_FOUR_WIRE;
		devc->acquisition_mq_flags |= SR_MQFLAG_FOUR_WIRE;
		devc->measurement_unit = SR_UNIT_OHM;
		parse_range_ohm(devc, function_byte);
	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_ADC) {
		devc->measurement_mq = SR_MQ_CURRENT;
		devc->measurement_mq_flags |= SR_MQFLAG_DC;
		devc->acquisition_mq_flags |= SR_MQFLAG_DC;
		devc->measurement_unit = SR_UNIT_AMPERE;
		parse_range_a(devc, function_byte);
	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_AAC) {
		devc->measurement_mq = SR_MQ_CURRENT;
		devc->measurement_mq_flags |= SR_MQFLAG_AC;
		devc->acquisition_mq_flags |= SR_MQFLAG_AC | SR_MQFLAG_RMS;
		devc->measurement_unit = SR_UNIT_AMPERE;
		parse_range_a(devc, function_byte);
	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_EXR) {
		devc->measurement_mq = SR_MQ_RESISTANCE;
		devc->measurement_unit = SR_UNIT_OHM;
		parse_range_ohm(devc, function_byte);
	}

	return SR_OK;
}

static int parse_status_byte(struct dev_context *devc, uint8_t status_byte)
{
	devc->trigger = TRIGGER_UNDEFINED;

	/* External Trigger */
	if ((status_byte & STATUS_EXT_TRIGGER) == STATUS_EXT_TRIGGER)
		devc->trigger = TRIGGER_EXTERNAL;

	/* Cal RAM */
	if ((status_byte & STATUS_CAL_RAM) == STATUS_CAL_RAM)
		devc->calibration = TRUE;
	else
		devc->calibration = FALSE;

	/* Front/Rear terminals */
	if ((status_byte & STATUS_FRONT_TERMINAL) == STATUS_FRONT_TERMINAL)
		devc->terminal = TERMINAL_FRONT;
	else
		devc->terminal = TERMINAL_REAR;

	/* 50Hz / 60Hz */
	if ((status_byte & STATUS_50HZ) == STATUS_50HZ)
		devc->line = LINE_50HZ;
	else
		devc->line = LINE_60HZ;

	/* Auto-Zero */
	if ((status_byte & STATUS_AUTO_ZERO) == STATUS_AUTO_ZERO)
		devc->auto_zero = TRUE;
	else
		devc->auto_zero = FALSE;

	/* Auto-Range */
	if ((status_byte & STATUS_AUTO_RANGE) == STATUS_AUTO_RANGE) {
		devc->acquisition_mq_flags |= SR_MQFLAG_AUTORANGE;
		devc->range_exp = -99;
	} else
		devc->acquisition_mq_flags &= ~SR_MQFLAG_AUTORANGE;

	/* Internal trigger */
	if ((status_byte & STATUS_INT_TRIGGER) == STATUS_INT_TRIGGER)
		devc->trigger = TRIGGER_INTERNAL;

	return SR_OK;
}

static int parse_srq_byte(uint8_t sqr_byte)
{
	(void)sqr_byte;

#if 0
	/* The ServiceReQuest register isn't used at the moment. */

	/* PON SRQ */
	if ((sqr_byte & SRQ_POWER_ON) == SRQ_POWER_ON)
		sr_spew("Power On SRQ or clear msg received");

	/* Cal failed SRQ */
	if ((sqr_byte & SRQ_CAL_FAILED) == SRQ_CAL_FAILED)
		sr_spew("CAL failed SRQ");

	/* Keyboard SRQ */
	if ((sqr_byte & SRQ_KEYBORD) == SRQ_KEYBORD)
		sr_spew("Keyboard SRQ");

	/* Hardware error SRQ */
	if ((sqr_byte & SRQ_HARDWARE_ERR) == SRQ_HARDWARE_ERR)
		sr_spew("Hardware error SRQ");

	/* Syntax error SRQ */
	if ((sqr_byte & SRQ_SYNTAX_ERR) == SRQ_SYNTAX_ERR)
		sr_spew("Syntax error SRQ");

	/* Every reading is available to the bus SRQ */
	if ((sqr_byte & SRQ_BUS_AVAIL) == SRQ_BUS_AVAIL)
		sr_spew("Every reading is available to the bus SRQ");
#endif

	return SR_OK;
}

static int parse_error_byte(uint8_t error_byte)
{
	int ret;

	ret = SR_OK;

	/* A/D link */
	if ((error_byte & ERROR_AD_LINK) == ERROR_AD_LINK) {
		sr_err("Failure in the A/D link");
		ret = SR_ERR;
	}

	/* A/D Self Test */
	if ((error_byte & ERROR_AD_SELF_TEST) == ERROR_AD_SELF_TEST) {
		sr_err("A/D has failed its internal Self Test");
		ret = SR_ERR;
	}

	/* A/D slope error */
	if ((error_byte & ERROR_AD_SLOPE) == ERROR_AD_SLOPE) {
		sr_err("There has been an A/D slope error");
		ret = SR_ERR;
	}

	/* ROM Selt Test */
	if ((error_byte & ERROR_ROM_SELF_TEST) == ERROR_ROM_SELF_TEST) {
		sr_err("The ROM Self Test has failed");
		ret = SR_ERR;
	}

	/* RAM Selt Test */
	if ((error_byte & ERROR_RAM_SELF_TEST) == ERROR_RAM_SELF_TEST) {
		sr_err("The RAM Self Test has failed");
		ret = SR_ERR;
	}

	/* Selt Test */
	if ((error_byte & ERROR_SELF_TEST) == ERROR_SELF_TEST) {
		sr_err("Self Test: Any of the CAL RAM locations have bad "
		       "checksums, or a range with a bad checksum is selected");
		ret = SR_ERR;
	}

	return ret;
}

SR_PRIV int hp_3478a_get_status_bytes(const struct sr_dev_inst *sdi)
{
	int ret;
	char *response;
	uint8_t function_byte, status_byte, srq_byte, error_byte;
	struct sr_scpi_dev_inst *scpi = sdi->conn;
	struct dev_context *devc = sdi->priv;

	ret = sr_scpi_get_string(scpi, "B", &response);
	if (ret != SR_OK)
		return ret;

	if (!response)
		return SR_ERR;

	function_byte = (uint8_t)response[0];
	status_byte = (uint8_t)response[1];
	srq_byte = (uint8_t)response[2];
	error_byte = (uint8_t)response[3];

	g_free(response);

	parse_function_byte(devc, function_byte);
	parse_status_byte(devc, status_byte);
	parse_srq_byte(srq_byte);
	ret = parse_error_byte(error_byte);

	return ret;
}

static void acq_send_measurement(struct sr_dev_inst *sdi)
{
	struct sr_datafeed_packet packet;
	struct sr_datafeed_analog analog;
	struct sr_analog_encoding encoding;
	struct sr_analog_meaning meaning;
	struct sr_analog_spec spec;
	struct dev_context *devc;
	float f;

	devc = sdi->priv;

	packet.type = SR_DF_ANALOG;
	packet.payload = &analog;

	sr_analog_init(&analog, &encoding, &meaning, &spec, devc->enc_digits);

	/* TODO: Implement NAN, depending on counts, range and value. */
	f = devc->measurement;
	analog.num_samples = 1;
	analog.data = &f;

	encoding.unitsize = sizeof(float);
	encoding.is_float = TRUE;
	encoding.digits = devc->enc_digits;

	meaning.mq = devc->measurement_mq;
	meaning.mqflags = devc->acquisition_mq_flags;
	meaning.unit = devc->measurement_unit;
	meaning.channels = sdi->channels;

	spec.spec_digits = devc->spec_digits;

	sr_session_send(sdi, &packet);
}

SR_PRIV int hp_3478a_receive_data(int fd, int revents, void *cb_data)
{
	struct sr_scpi_dev_inst *scpi;
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	char status_register;

	(void)fd;
	(void)revents;

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

	scpi = sdi->conn;

	/*
	 * TODO: Wait for SRQ from the DMM when a new measurement is available.
	 *       For now, we don't wait for a SRQ, but just do a SPoll and
	 *       check the Data Ready bit (0x01).
	 *       This is necessary, because (1) reading a value will block the
	 *       bus until a measurement is available and (2) when switching
	 *       ranges, there could be a timeout.
	 */
	if (sr_scpi_gpib_spoll(scpi, &status_register) != SR_OK)
		return FALSE;
	if (!(((uint8_t)status_register) & 0x01))
		return TRUE;

	/* Get a reading from the DMM. */
	if (sr_scpi_get_double(scpi, NULL, &devc->measurement) != SR_OK)
		return FALSE;

	/* Check for overflow. */
	if (devc->measurement >= 9.998e+9)
		devc->measurement = INFINITY;

	/*
	 * This is necessary to get the actual range for the encoding digits.
	 * Must be called after reading the value, because it resets the
	 * status register!
	 */
	if (hp_3478a_get_status_bytes(sdi) != SR_OK)
		return FALSE;

	acq_send_measurement(sdi);
	sr_sw_limits_update_samples_read(&devc->limits, 1);

	if (sr_sw_limits_check(&devc->limits))
		sr_dev_acquisition_stop(sdi);

	return TRUE;
}
Commit	Line	Data
	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2017-2018 Frank Stettner <frank-stettner@gmx.net>
	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 <math.h>
	22	#include <stdlib.h>
	23	#include "scpi.h"
	24	#include "protocol.h"
	25
	26	static int set_mq_volt(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);
	27	static int set_mq_amp(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);
	28	static int set_mq_ohm(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags);
	29
	30	static const struct {
	31	enum sr_mq mq;
	32	int (set_mode)(struct sr_scpi_dev_inst scpi, enum sr_mqflag flags);
	33	} sr_mq_to_cmd_map[] = {
	34	{ SR_MQ_VOLTAGE, set_mq_volt },
	35	{ SR_MQ_CURRENT, set_mq_amp },
	36	{ SR_MQ_RESISTANCE, set_mq_ohm },
	37	};
	38
	39	static int set_mq_volt(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags)
	40	{
	41	if ((flags & SR_MQFLAG_AC) != SR_MQFLAG_AC &&
	42	(flags & SR_MQFLAG_DC) != SR_MQFLAG_DC)
	43	return SR_ERR_NA;
	44
	45	return sr_scpi_send(scpi, "%s",
	46	((flags & SR_MQFLAG_AC) == SR_MQFLAG_AC) ? "F2" : "F1");
	47	}
	48
	49	static int set_mq_amp(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags)
	50	{
	51	if ((flags & SR_MQFLAG_AC) != SR_MQFLAG_AC &&
	52	(flags & SR_MQFLAG_DC) != SR_MQFLAG_DC)
	53	return SR_ERR_NA;
	54
	55	return sr_scpi_send(scpi, "%s", (flags & SR_MQFLAG_AC) ? "F6" : "F5");
	56	}
	57
	58	static int set_mq_ohm(struct sr_scpi_dev_inst *scpi, enum sr_mqflag flags)
	59	{
	60	return sr_scpi_send(scpi, "%s",
	61	(flags & SR_MQFLAG_FOUR_WIRE) ? "F4" : "F3");
	62	}
	63
	64	SR_PRIV int hp_3478a_set_mq(const struct sr_dev_inst *sdi, enum sr_mq mq,
	65	enum sr_mqflag mq_flags)
	66	{
	67	int ret;
	68	size_t i;
	69	struct sr_scpi_dev_inst *scpi = sdi->conn;
	70	struct dev_context *devc = sdi->priv;
	71
	72	/* No need to send command if we're not changing measurement type. */
	73	if (devc->measurement_mq == mq &&
	74	((devc->measurement_mq_flags & mq_flags) == mq_flags))
	75	return SR_OK;
	76
	77	for (i = 0; i < ARRAY_SIZE(sr_mq_to_cmd_map); i++) {
	78	if (sr_mq_to_cmd_map[i].mq != mq)
	79	continue;
	80
	81	ret = sr_mq_to_cmd_map[i].set_mode(scpi, mq_flags);
	82	if (ret != SR_OK)
	83	return ret;
	84
	85	ret = hp_3478a_get_status_bytes(sdi);
	86	return ret;
	87	}
	88
	89	return SR_ERR_NA;
	90	}
	91
	92	SR_PRIV int hp_3478a_set_range(const struct sr_dev_inst *sdi, int range_exp)
	93	{
	94	int ret;
	95	struct sr_scpi_dev_inst *scpi = sdi->conn;
	96	struct dev_context *devc = sdi->priv;
	97
	98	/* No need to send command if we're not changing the range. */
	99	if (devc->range_exp == range_exp)
	100	return SR_OK;
	101
	102	/* -99 is a dummy exponent for auto ranging. */
	103	if (range_exp == -99)
	104	ret = sr_scpi_send(scpi, "RA");
	105	else
	106	ret = sr_scpi_send(scpi, "R%i", range_exp);
	107	if (ret != SR_OK)
	108	return ret;
	109
	110	return hp_3478a_get_status_bytes(sdi);
	111	}
	112
	113	SR_PRIV int hp_3478a_set_digits(const struct sr_dev_inst *sdi, uint8_t digits)
	114	{
	115	int ret;
	116	struct sr_scpi_dev_inst *scpi = sdi->conn;
	117	struct dev_context *devc = sdi->priv;
	118
	119	/* No need to send command if we're not changing the range. */
	120	if (devc->spec_digits == digits)
	121	return SR_OK;
	122
	123	/* digits are based on devc->spec_digits, so we have to substract 1 */
	124	ret = sr_scpi_send(scpi, "N%i", digits-1);
	125	if (ret != SR_OK)
	126	return ret;
	127
	128	return hp_3478a_get_status_bytes(sdi);
	129	}
	130
	131	static int parse_range_vdc(struct dev_context *devc, uint8_t range_byte)
	132	{
	133	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30MV) {
	134	devc->range_exp = -2;
	135	devc->enc_digits = devc->spec_digits - 2;
	136	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300MV) {
	137	devc->range_exp = -1;
	138	devc->enc_digits = devc->spec_digits - 3;
	139	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_3V) {
	140	devc->range_exp = 0;
	141	devc->enc_digits = devc->spec_digits - 1;
	142	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30V) {
	143	devc->range_exp = 1;
	144	devc->enc_digits = devc->spec_digits - 2;
	145	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300V) {
	146	devc->range_exp = 2;
	147	devc->enc_digits = devc->spec_digits - 3;
	148	} else
	149	return SR_ERR_DATA;
	150
	151	return SR_OK;
	152	}
	153
	154	static int parse_range_vac(struct dev_context *devc, uint8_t range_byte)
	155	{
	156	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300MV) {
	157	devc->range_exp = -1;
	158	devc->enc_digits = devc->spec_digits - 3;
	159	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_3V) {
	160	devc->range_exp = 0;
	161	devc->enc_digits = devc->spec_digits - 1;
	162	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_30V) {
	163	devc->range_exp = 1;
	164	devc->enc_digits = devc->spec_digits - 2;
	165	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300V) {
	166	devc->range_exp = 2;
	167	devc->enc_digits = devc->spec_digits - 3;
	168	} else
	169	return SR_ERR_DATA;
	170
	171	return SR_OK;
	172	}
	173
	174	static int parse_range_a(struct dev_context *devc, uint8_t range_byte)
	175	{
	176	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_300MA) {
	177	devc->range_exp = -1;
	178	devc->enc_digits = devc->spec_digits - 3;
	179	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_3A) {
	180	devc->range_exp = 0;
	181	devc->enc_digits = devc->spec_digits - 1;
	182	} else
	183	return SR_ERR_DATA;
	184
	185	return SR_OK;
	186	}
	187
	188	static int parse_range_ohm(struct dev_context *devc, uint8_t range_byte)
	189	{
	190	if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30R) {
	191	devc->range_exp = 1;
	192	devc->enc_digits = devc->spec_digits - 2;
	193	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300R) {
	194	devc->range_exp = 2;
	195	devc->enc_digits = devc->spec_digits - 3;
	196	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3KR) {
	197	devc->range_exp = 3;
	198	devc->enc_digits = devc->spec_digits - 1;
	199	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30KR) {
	200	devc->range_exp = 4;
	201	devc->enc_digits = devc->spec_digits - 2;
	202	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300KR) {
	203	devc->range_exp = 5;
	204	devc->enc_digits = devc->spec_digits - 3;
	205	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3MR) {
	206	devc->range_exp = 6;
	207	devc->enc_digits = devc->spec_digits - 1;
	208	} else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30MR) {
	209	devc->range_exp = 7;
	210	devc->enc_digits = devc->spec_digits - 2;
	211	} else
	212	return SR_ERR_DATA;
	213
	214	return SR_OK;
	215	}
	216
	217	static int parse_function_byte(struct dev_context *devc, uint8_t function_byte)
	218	{
	219	/* Digits / Resolution (spec_digits must be set before range parsing) */
	220	if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_5_5)
	221	devc->spec_digits = 6;
	222	else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_4_5)
	223	devc->spec_digits = 5;
	224	else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_3_5)
	225	devc->spec_digits = 4;
	226	else
	227	return SR_ERR_DATA;
	228
	229	/* Function + Range */
	230	devc->measurement_mq_flags = 0;
	231	devc->acquisition_mq_flags = 0;
	232	if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_VDC) {
	233	devc->measurement_mq = SR_MQ_VOLTAGE;
	234	devc->measurement_mq_flags \|= SR_MQFLAG_DC;
	235	devc->acquisition_mq_flags \|= SR_MQFLAG_DC;
	236	devc->measurement_unit = SR_UNIT_VOLT;
	237	parse_range_vdc(devc, function_byte);
	238	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_VAC) {
	239	devc->measurement_mq = SR_MQ_VOLTAGE;
	240	devc->measurement_mq_flags \|= SR_MQFLAG_AC;
	241	devc->acquisition_mq_flags \|= SR_MQFLAG_AC \| SR_MQFLAG_RMS;
	242	devc->measurement_unit = SR_UNIT_VOLT;
	243	parse_range_vac(devc, function_byte);
	244	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_2WR) {
	245	devc->measurement_mq = SR_MQ_RESISTANCE;
	246	devc->measurement_unit = SR_UNIT_OHM;
	247	parse_range_ohm(devc, function_byte);
	248	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_4WR) {
	249	devc->measurement_mq = SR_MQ_RESISTANCE;
	250	devc->measurement_mq_flags \|= SR_MQFLAG_FOUR_WIRE;
	251	devc->acquisition_mq_flags \|= SR_MQFLAG_FOUR_WIRE;
	252	devc->measurement_unit = SR_UNIT_OHM;
	253	parse_range_ohm(devc, function_byte);
	254	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_ADC) {
	255	devc->measurement_mq = SR_MQ_CURRENT;
	256	devc->measurement_mq_flags \|= SR_MQFLAG_DC;
	257	devc->acquisition_mq_flags \|= SR_MQFLAG_DC;
	258	devc->measurement_unit = SR_UNIT_AMPERE;
	259	parse_range_a(devc, function_byte);
	260	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_AAC) {
	261	devc->measurement_mq = SR_MQ_CURRENT;
	262	devc->measurement_mq_flags \|= SR_MQFLAG_AC;
	263	devc->acquisition_mq_flags \|= SR_MQFLAG_AC \| SR_MQFLAG_RMS;
	264	devc->measurement_unit = SR_UNIT_AMPERE;
	265	parse_range_a(devc, function_byte);
	266	} else if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_EXR) {
	267	devc->measurement_mq = SR_MQ_RESISTANCE;
	268	devc->measurement_unit = SR_UNIT_OHM;
	269	parse_range_ohm(devc, function_byte);
	270	}
	271
	272	return SR_OK;
	273	}
	274
	275	static int parse_status_byte(struct dev_context *devc, uint8_t status_byte)
	276	{
	277	devc->trigger = TRIGGER_UNDEFINED;
	278
	279	/* External Trigger */
	280	if ((status_byte & STATUS_EXT_TRIGGER) == STATUS_EXT_TRIGGER)
	281	devc->trigger = TRIGGER_EXTERNAL;
	282
	283	/* Cal RAM */
	284	if ((status_byte & STATUS_CAL_RAM) == STATUS_CAL_RAM)
	285	devc->calibration = TRUE;
	286	else
	287	devc->calibration = FALSE;
	288
	289	/* Front/Rear terminals */
	290	if ((status_byte & STATUS_FRONT_TERMINAL) == STATUS_FRONT_TERMINAL)
	291	devc->terminal = TERMINAL_FRONT;
	292	else
	293	devc->terminal = TERMINAL_REAR;
	294
	295	/* 50Hz / 60Hz */
	296	if ((status_byte & STATUS_50HZ) == STATUS_50HZ)
	297	devc->line = LINE_50HZ;
	298	else
	299	devc->line = LINE_60HZ;
	300
	301	/* Auto-Zero */
	302	if ((status_byte & STATUS_AUTO_ZERO) == STATUS_AUTO_ZERO)
	303	devc->auto_zero = TRUE;
	304	else
	305	devc->auto_zero = FALSE;
	306
	307	/* Auto-Range */
	308	if ((status_byte & STATUS_AUTO_RANGE) == STATUS_AUTO_RANGE) {
	309	devc->acquisition_mq_flags \|= SR_MQFLAG_AUTORANGE;
	310	devc->range_exp = -99;
	311	} else
	312	devc->acquisition_mq_flags &= ~SR_MQFLAG_AUTORANGE;
	313
	314	/* Internal trigger */
	315	if ((status_byte & STATUS_INT_TRIGGER) == STATUS_INT_TRIGGER)
	316	devc->trigger = TRIGGER_INTERNAL;
	317
	318	return SR_OK;
	319	}
	320
	321	static int parse_srq_byte(uint8_t sqr_byte)
	322	{
	323	(void)sqr_byte;
	324
	325	#if 0
	326	/* The ServiceReQuest register isn't used at the moment. */
	327
	328	/* PON SRQ */
	329	if ((sqr_byte & SRQ_POWER_ON) == SRQ_POWER_ON)
	330	sr_spew("Power On SRQ or clear msg received");
	331
	332	/* Cal failed SRQ */
	333	if ((sqr_byte & SRQ_CAL_FAILED) == SRQ_CAL_FAILED)
	334	sr_spew("CAL failed SRQ");
	335
	336	/* Keyboard SRQ */
	337	if ((sqr_byte & SRQ_KEYBORD) == SRQ_KEYBORD)
	338	sr_spew("Keyboard SRQ");
	339
	340	/* Hardware error SRQ */
	341	if ((sqr_byte & SRQ_HARDWARE_ERR) == SRQ_HARDWARE_ERR)
	342	sr_spew("Hardware error SRQ");
	343
	344	/* Syntax error SRQ */
	345	if ((sqr_byte & SRQ_SYNTAX_ERR) == SRQ_SYNTAX_ERR)
	346	sr_spew("Syntax error SRQ");
	347
	348	/* Every reading is available to the bus SRQ */
	349	if ((sqr_byte & SRQ_BUS_AVAIL) == SRQ_BUS_AVAIL)
	350	sr_spew("Every reading is available to the bus SRQ");
	351	#endif
	352
	353	return SR_OK;
	354	}
	355
	356	static int parse_error_byte(uint8_t error_byte)
	357	{
	358	int ret;
	359
	360	ret = SR_OK;
	361
	362	/* A/D link */
	363	if ((error_byte & ERROR_AD_LINK) == ERROR_AD_LINK) {
	364	sr_err("Failure in the A/D link");
	365	ret = SR_ERR;
	366	}
	367
	368	/* A/D Self Test */
	369	if ((error_byte & ERROR_AD_SELF_TEST) == ERROR_AD_SELF_TEST) {
	370	sr_err("A/D has failed its internal Self Test");
	371	ret = SR_ERR;
	372	}
	373
	374	/* A/D slope error */
	375	if ((error_byte & ERROR_AD_SLOPE) == ERROR_AD_SLOPE) {
	376	sr_err("There has been an A/D slope error");
	377	ret = SR_ERR;
	378	}
	379
	380	/* ROM Selt Test */
	381	if ((error_byte & ERROR_ROM_SELF_TEST) == ERROR_ROM_SELF_TEST) {
	382	sr_err("The ROM Self Test has failed");
	383	ret = SR_ERR;
	384	}
	385
	386	/* RAM Selt Test */
	387	if ((error_byte & ERROR_RAM_SELF_TEST) == ERROR_RAM_SELF_TEST) {
	388	sr_err("The RAM Self Test has failed");
	389	ret = SR_ERR;
	390	}
	391
	392	/* Selt Test */
	393	if ((error_byte & ERROR_SELF_TEST) == ERROR_SELF_TEST) {
	394	sr_err("Self Test: Any of the CAL RAM locations have bad "
	395	"checksums, or a range with a bad checksum is selected");
	396	ret = SR_ERR;
	397	}
	398
	399	return ret;
	400	}
	401
	402	SR_PRIV int hp_3478a_get_status_bytes(const struct sr_dev_inst *sdi)
	403	{
	404	int ret;
	405	char *response;
	406	uint8_t function_byte, status_byte, srq_byte, error_byte;
	407	struct sr_scpi_dev_inst *scpi = sdi->conn;
	408	struct dev_context *devc = sdi->priv;
	409
	410	ret = sr_scpi_get_string(scpi, "B", &response);
	411	if (ret != SR_OK)
	412	return ret;
	413
	414	if (!response)
	415	return SR_ERR;
	416
	417	function_byte = (uint8_t)response[0];
	418	status_byte = (uint8_t)response[1];
	419	srq_byte = (uint8_t)response[2];
	420	error_byte = (uint8_t)response[3];
	421
	422	g_free(response);
	423
	424	parse_function_byte(devc, function_byte);
	425	parse_status_byte(devc, status_byte);
	426	parse_srq_byte(srq_byte);
	427	ret = parse_error_byte(error_byte);
	428
	429	return ret;
	430	}
	431
	432	static void acq_send_measurement(struct sr_dev_inst *sdi)
	433	{
	434	struct sr_datafeed_packet packet;
	435	struct sr_datafeed_analog analog;
	436	struct sr_analog_encoding encoding;
	437	struct sr_analog_meaning meaning;
	438	struct sr_analog_spec spec;
	439	struct dev_context *devc;
	440	float f;
	441
	442	devc = sdi->priv;
	443
	444	packet.type = SR_DF_ANALOG;
	445	packet.payload = &analog;
	446
	447	sr_analog_init(&analog, &encoding, &meaning, &spec, devc->enc_digits);
	448
	449	/* TODO: Implement NAN, depending on counts, range and value. */
	450	f = devc->measurement;
	451	analog.num_samples = 1;
	452	analog.data = &f;
	453
	454	encoding.unitsize = sizeof(float);
	455	encoding.is_float = TRUE;
	456	encoding.digits = devc->enc_digits;
	457
	458	meaning.mq = devc->measurement_mq;
	459	meaning.mqflags = devc->acquisition_mq_flags;
	460	meaning.unit = devc->measurement_unit;
	461	meaning.channels = sdi->channels;
	462
	463	spec.spec_digits = devc->spec_digits;
	464
	465	sr_session_send(sdi, &packet);
	466	}
	467
	468	SR_PRIV int hp_3478a_receive_data(int fd, int revents, void *cb_data)
	469	{
	470	struct sr_scpi_dev_inst *scpi;
	471	struct sr_dev_inst *sdi;
	472	struct dev_context *devc;
	473	char status_register;
	474
	475	(void)fd;
	476	(void)revents;
	477
	478	if (!(sdi = cb_data) \|\| !(devc = sdi->priv))
	479	return TRUE;
	480
	481	scpi = sdi->conn;
	482
	483	/*
	484	* TODO: Wait for SRQ from the DMM when a new measurement is available.
	485	* For now, we don't wait for a SRQ, but just do a SPoll and
	486	* check the Data Ready bit (0x01).
	487	* This is necessary, because (1) reading a value will block the
	488	* bus until a measurement is available and (2) when switching
	489	* ranges, there could be a timeout.
	490	*/
	491	if (sr_scpi_gpib_spoll(scpi, &status_register) != SR_OK)
	492	return FALSE;
	493	if (!(((uint8_t)status_register) & 0x01))
	494	return TRUE;
	495
	496	/* Get a reading from the DMM. */
	497	if (sr_scpi_get_double(scpi, NULL, &devc->measurement) != SR_OK)
	498	return FALSE;
	499
	500	/* Check for overflow. */
	501	if (devc->measurement >= 9.998e+9)
	502	devc->measurement = INFINITY;
	503
	504	/*
	505	* This is necessary to get the actual range for the encoding digits.
	506	* Must be called after reading the value, because it resets the
	507	* status register!
	508	*/
	509	if (hp_3478a_get_status_bytes(sdi) != SR_OK)
	510	return FALSE;
	511
	512	acq_send_measurement(sdi);
	513	sr_sw_limits_update_samples_read(&devc->limits, 1);
	514
	515	if (sr_sw_limits_check(&devc->limits))
	516	sr_dev_acquisition_stop(sdi);
	517
	518	return TRUE;
	519	}