[libsigrok.git] / src / hardware / korad-kaxxxxp / protocol.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2015 Hannu Vuolasaho <vuokkosetae@gmail.com>
 * Copyright (C) 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 "protocol.h"

#define REQ_TIMEOUT_MS 500
#define DEVICE_PROCESSING_TIME_MS 80

SR_PRIV int korad_kaxxxxp_send_cmd(struct sr_serial_dev_inst *serial,
				const char *cmd)
{
	int ret;

	sr_dbg("Sending '%s'.", cmd);
	if ((ret = serial_write_blocking(serial, cmd, strlen(cmd), 0)) < 0) {
		sr_err("Error sending command: %d.", ret);
		return ret;
	}

	return ret;
}

SR_PRIV int korad_kaxxxxp_read_chars(struct sr_serial_dev_inst *serial,
				int count, char *buf)
{
	int ret, received, turns;

	received = 0;
	turns = 0;

	do {
		if ((ret = serial_read_blocking(serial, buf + received,
				count - received,
				serial_timeout(serial, count))) < 0) {
			sr_err("Error %d reading %d bytes from device.",
			       ret, count);
			return ret;
		}
		received += ret;
		turns++;
	} while ((received < count) && (turns < 100));

	buf[count] = 0;

	sr_spew("Received: '%s'.", buf);

	return ret;
}

static void give_device_time_to_process(struct dev_context *devc)
{
	int64_t sleeping_time;

	sleeping_time = devc->req_sent_at + (DEVICE_PROCESSING_TIME_MS * 1000);
	sleeping_time -= g_get_monotonic_time();

	if (sleeping_time > 0) {
		g_usleep(sleeping_time);
		sr_spew("Sleeping for processing %" PRIi64 " usec", sleeping_time);
	}
}

SR_PRIV int korad_kaxxxxp_set_value(struct sr_serial_dev_inst *serial,
				int target, struct dev_context *devc)
{
	char *msg;
	const char *cmd;
	float value;
	int ret;

	g_mutex_lock(&devc->rw_mutex);
	give_device_time_to_process(devc);

	switch (target) {
	case KAXXXXP_CURRENT:
	case KAXXXXP_VOLTAGE:
	case KAXXXXP_STATUS:
		sr_err("Can't set measurable parameter %d.", target);
		g_mutex_unlock(&devc->rw_mutex);
		return SR_ERR;
	case KAXXXXP_CURRENT_LIMIT:
		cmd = "ISET1:%05.3f";
		value = devc->set_current_limit;
		break;
	case KAXXXXP_VOLTAGE_TARGET:
		cmd = "VSET1:%05.2f";
		value = devc->set_voltage_target;
		break;
	case KAXXXXP_OUTPUT:
		cmd = "OUT%01.0f";
		value = (devc->set_output_enabled) ? 1 : 0;
		/* Set value back to recognize changes */
		devc->output_enabled = devc->set_output_enabled;
		break;
	case KAXXXXP_BEEP:
		cmd = "BEEP%01.0f";
		value = (devc->set_beep_enabled) ? 1 : 0;
		break;
	case KAXXXXP_OCP:
		cmd = "OCP%01.0f";
		value = (devc->set_ocp_enabled) ? 1 : 0;
		/* Set value back to recognize changes */
		devc->ocp_enabled = devc->set_ocp_enabled;
		break;
	case KAXXXXP_OVP:
		cmd = "OVP%01.0f";
		value = (devc->set_ovp_enabled) ? 1 : 0;
		/* Set value back to recognize changes */
		devc->ovp_enabled = devc->set_ovp_enabled;
		break;
	case KAXXXXP_SAVE:
		cmd = "SAV%01.0f";
		if (devc->program < 1 || devc->program > 5) {
			sr_err("Only programs 1-5 supported and %d isn't "
			       "between them.", devc->program);
			g_mutex_unlock(&devc->rw_mutex);
			return SR_ERR;
		}
		value = devc->program;
		break;
	case KAXXXXP_RECALL:
		cmd = "RCL%01.0f";
		if (devc->program < 1 || devc->program > 5) {
			sr_err("Only programs 1-5 supported and %d isn't "
			       "between them.", devc->program);
			g_mutex_unlock(&devc->rw_mutex);
			return SR_ERR;
		}
		value = devc->program;
		break;
	default:
		sr_err("Don't know how to set %d.", target);
		g_mutex_unlock(&devc->rw_mutex);
		return SR_ERR;
	}

	msg = g_malloc0(20 + 1);
	if (cmd)
		sr_snprintf_ascii(msg, 20, cmd, value);

	ret = korad_kaxxxxp_send_cmd(serial, msg);
	devc->req_sent_at = g_get_monotonic_time();
	g_free(msg);

	g_mutex_unlock(&devc->rw_mutex);

	return ret;
}

SR_PRIV int korad_kaxxxxp_get_value(struct sr_serial_dev_inst *serial,
				int target, struct dev_context *devc)
{
	int ret, count;
	char reply[6];
	float *value;
	char status_byte;

	g_mutex_lock(&devc->rw_mutex);
	give_device_time_to_process(devc);

	value = NULL;
	count = 5;

	switch (target) {
	case KAXXXXP_CURRENT:
		/* Read current from device. */
		ret = korad_kaxxxxp_send_cmd(serial, "IOUT1?");
		value = &(devc->current);
		break;
	case KAXXXXP_CURRENT_LIMIT:
		/* Read set current from device. */
		ret = korad_kaxxxxp_send_cmd(serial, "ISET1?");
		value = &(devc->current_limit);
		break;
	case KAXXXXP_VOLTAGE:
		/* Read voltage from device. */
		ret = korad_kaxxxxp_send_cmd(serial, "VOUT1?");
		value = &(devc->voltage);
		break;
	case KAXXXXP_VOLTAGE_TARGET:
		/* Read set voltage from device. */
		ret = korad_kaxxxxp_send_cmd(serial, "VSET1?");
		value = &(devc->voltage_target);
		break;
	case KAXXXXP_STATUS:
	case KAXXXXP_OUTPUT:
	case KAXXXXP_OCP:
	case KAXXXXP_OVP:
		/* Read status from device. */
		ret = korad_kaxxxxp_send_cmd(serial, "STATUS?");
		count = 1;
		break;
	default:
		sr_err("Don't know how to query %d.", target);
		g_mutex_unlock(&devc->rw_mutex);
		return SR_ERR;
	}

	devc->req_sent_at = g_get_monotonic_time();

	if ((ret = korad_kaxxxxp_read_chars(serial, count, reply)) < 0) {
		g_mutex_unlock(&devc->rw_mutex);
		return ret;
	}

	reply[count] = 0;

	if (value) {
		sr_atof_ascii((const char *)&reply, value);
		sr_dbg("value: %f", *value);
	} else {
		/* We have status reply. */
		status_byte = reply[0];
		/* Constant current */
		devc->cc_mode[0] = !(status_byte & (1 << 0)); /* Channel one */
		devc->cc_mode[1] = !(status_byte & (1 << 1)); /* Channel two */
		/*
		 * Tracking
		 * status_byte & ((1 << 2) | (1 << 3))
		 * 00 independent 01 series 11 parallel
		 */
		devc->beep_enabled = (1 << 4);
		devc->ocp_enabled = (status_byte & (1 << 5));
		devc->output_enabled = (status_byte & (1 << 6));
		/* Velleman LABPS3005 quirk */
		if (devc->output_enabled)
			devc->ovp_enabled = (status_byte & (1 << 7));
		sr_dbg("Status: 0x%02x", status_byte);
		sr_spew("Status: CH1: constant %s CH2: constant %s. "
			"Tracking would be %s. Device is "
			"%s and %s. Buttons are %s. Output is %s "
			"and extra bit is %s.",
			(status_byte & (1 << 0)) ? "voltage" : "current",
			(status_byte & (1 << 1)) ? "voltage" : "current",
			(status_byte & (1 << 2)) ? "parallel" : "series",
			(status_byte & (1 << 3)) ? "tracking" : "independent",
			(status_byte & (1 << 4)) ? "beeping" : "silent",
			(status_byte & (1 << 5)) ? "locked" : "unlocked",
			(status_byte & (1 << 6)) ? "enabled" : "disabled",
			(status_byte & (1 << 7)) ? "true" : "false");
	}

	/* Read the sixth byte from ISET? BUG workaround. */
	if (target == KAXXXXP_CURRENT_LIMIT)
		serial_read_blocking(serial, &status_byte, 1, 10);

	g_mutex_unlock(&devc->rw_mutex);

	return ret;
}

SR_PRIV int korad_kaxxxxp_get_all_values(struct sr_serial_dev_inst *serial,
				struct dev_context *devc)
{
	int ret, target;

	for (target = KAXXXXP_CURRENT;
			target <= KAXXXXP_STATUS; target++) {
		if ((ret = korad_kaxxxxp_get_value(serial, target, devc)) < 0)
			return ret;
	}

	return ret;
}

static void next_measurement(struct dev_context *devc)
{
	switch (devc->acquisition_target) {
	case KAXXXXP_CURRENT:
		devc->acquisition_target = KAXXXXP_VOLTAGE;
		break;
	case KAXXXXP_VOLTAGE:
		devc->acquisition_target = KAXXXXP_STATUS;
		break;
	case KAXXXXP_STATUS:
		devc->acquisition_target = KAXXXXP_CURRENT;
		break;
	default:
		devc->acquisition_target = KAXXXXP_CURRENT;
		sr_err("Invalid target for next acquisition.");
	}
}

SR_PRIV int korad_kaxxxxp_receive_data(int fd, int revents, void *cb_data)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	struct sr_serial_dev_inst *serial;
	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;
	GSList *l;

	(void)fd;
	(void)revents;

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

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

	serial = sdi->conn;

	/* Get the value. */
	korad_kaxxxxp_get_value(serial, devc->acquisition_target, devc);

	/* Note: digits/spec_digits will be overridden later. */
	sr_analog_init(&analog, &encoding, &meaning, &spec, 0);

	/* Send the value forward. */
	packet.type = SR_DF_ANALOG;
	packet.payload = &analog;
	analog.num_samples = 1;
	l = g_slist_copy(sdi->channels);
	if (devc->acquisition_target == KAXXXXP_CURRENT) {
		l = g_slist_remove_link(l, g_slist_nth(l, 0));
		analog.meaning->channels = l;
		analog.meaning->mq = SR_MQ_CURRENT;
		analog.meaning->unit = SR_UNIT_AMPERE;
		analog.meaning->mqflags = SR_MQFLAG_DC;
		analog.encoding->digits = 3;
		analog.spec->spec_digits = 3;
		analog.data = &devc->current;
		sr_session_send(sdi, &packet);
	} else if (devc->acquisition_target == KAXXXXP_VOLTAGE) {
		l = g_slist_remove_link(l, g_slist_nth(l, 1));
		analog.meaning->channels = l;
		analog.meaning->mq = SR_MQ_VOLTAGE;
		analog.meaning->unit = SR_UNIT_VOLT;
		analog.meaning->mqflags = SR_MQFLAG_DC;
		analog.encoding->digits = 2;
		analog.spec->spec_digits = 2;
		analog.data = &devc->voltage;
		sr_session_send(sdi, &packet);
		sr_sw_limits_update_samples_read(&devc->limits, 1);
	}
	next_measurement(devc);

	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) 2015 Hannu Vuolasaho <vuokkosetae@gmail.com>
	5	* Copyright (C) 2018 Frank Stettner <frank-stettner@gmx.net>
	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
	21	#include <config.h>
	22	#include "protocol.h"
	23
	24	#define REQ_TIMEOUT_MS 500
	25	#define DEVICE_PROCESSING_TIME_MS 80
	26
	27	SR_PRIV int korad_kaxxxxp_send_cmd(struct sr_serial_dev_inst *serial,
	28	const char *cmd)
	29	{
	30	int ret;
	31
	32	sr_dbg("Sending '%s'.", cmd);
	33	if ((ret = serial_write_blocking(serial, cmd, strlen(cmd), 0)) < 0) {
	34	sr_err("Error sending command: %d.", ret);
	35	return ret;
	36	}
	37
	38	return ret;
	39	}
	40
	41	SR_PRIV int korad_kaxxxxp_read_chars(struct sr_serial_dev_inst *serial,
	42	int count, char *buf)
	43	{
	44	int ret, received, turns;
	45
	46	received = 0;
	47	turns = 0;
	48
	49	do {
	50	if ((ret = serial_read_blocking(serial, buf + received,
	51	count - received,
	52	serial_timeout(serial, count))) < 0) {
	53	sr_err("Error %d reading %d bytes from device.",
	54	ret, count);
	55	return ret;
	56	}
	57	received += ret;
	58	turns++;
	59	} while ((received < count) && (turns < 100));
	60
	61	buf[count] = 0;
	62
	63	sr_spew("Received: '%s'.", buf);
	64
	65	return ret;
	66	}
	67
	68	static void give_device_time_to_process(struct dev_context *devc)
	69	{
	70	int64_t sleeping_time;
	71
	72	sleeping_time = devc->req_sent_at + (DEVICE_PROCESSING_TIME_MS * 1000);
	73	sleeping_time -= g_get_monotonic_time();
	74
	75	if (sleeping_time > 0) {
	76	g_usleep(sleeping_time);
	77	sr_spew("Sleeping for processing %" PRIi64 " usec", sleeping_time);
	78	}
	79	}
	80
	81	SR_PRIV int korad_kaxxxxp_set_value(struct sr_serial_dev_inst *serial,
	82	int target, struct dev_context *devc)
	83	{
	84	char *msg;
	85	const char *cmd;
	86	float value;
	87	int ret;
	88
	89	g_mutex_lock(&devc->rw_mutex);
	90	give_device_time_to_process(devc);
	91
	92	switch (target) {
	93	case KAXXXXP_CURRENT:
	94	case KAXXXXP_VOLTAGE:
	95	case KAXXXXP_STATUS:
	96	sr_err("Can't set measurable parameter %d.", target);
	97	g_mutex_unlock(&devc->rw_mutex);
	98	return SR_ERR;
	99	case KAXXXXP_CURRENT_LIMIT:
	100	cmd = "ISET1:%05.3f";
	101	value = devc->set_current_limit;
	102	break;
	103	case KAXXXXP_VOLTAGE_TARGET:
	104	cmd = "VSET1:%05.2f";
	105	value = devc->set_voltage_target;
	106	break;
	107	case KAXXXXP_OUTPUT:
	108	cmd = "OUT%01.0f";
	109	value = (devc->set_output_enabled) ? 1 : 0;
	110	/* Set value back to recognize changes */
	111	devc->output_enabled = devc->set_output_enabled;
	112	break;
	113	case KAXXXXP_BEEP:
	114	cmd = "BEEP%01.0f";
	115	value = (devc->set_beep_enabled) ? 1 : 0;
	116	break;
	117	case KAXXXXP_OCP:
	118	cmd = "OCP%01.0f";
	119	value = (devc->set_ocp_enabled) ? 1 : 0;
	120	/* Set value back to recognize changes */
	121	devc->ocp_enabled = devc->set_ocp_enabled;
	122	break;
	123	case KAXXXXP_OVP:
	124	cmd = "OVP%01.0f";
	125	value = (devc->set_ovp_enabled) ? 1 : 0;
	126	/* Set value back to recognize changes */
	127	devc->ovp_enabled = devc->set_ovp_enabled;
	128	break;
	129	case KAXXXXP_SAVE:
	130	cmd = "SAV%01.0f";
	131	if (devc->program < 1 \|\| devc->program > 5) {
	132	sr_err("Only programs 1-5 supported and %d isn't "
	133	"between them.", devc->program);
	134	g_mutex_unlock(&devc->rw_mutex);
	135	return SR_ERR;
	136	}
	137	value = devc->program;
	138	break;
	139	case KAXXXXP_RECALL:
	140	cmd = "RCL%01.0f";
	141	if (devc->program < 1 \|\| devc->program > 5) {
	142	sr_err("Only programs 1-5 supported and %d isn't "
	143	"between them.", devc->program);
	144	g_mutex_unlock(&devc->rw_mutex);
	145	return SR_ERR;
	146	}
	147	value = devc->program;
	148	break;
	149	default:
	150	sr_err("Don't know how to set %d.", target);
	151	g_mutex_unlock(&devc->rw_mutex);
	152	return SR_ERR;
	153	}
	154
	155	msg = g_malloc0(20 + 1);
	156	if (cmd)
	157	sr_snprintf_ascii(msg, 20, cmd, value);
	158
	159	ret = korad_kaxxxxp_send_cmd(serial, msg);
	160	devc->req_sent_at = g_get_monotonic_time();
	161	g_free(msg);
	162
	163	g_mutex_unlock(&devc->rw_mutex);
	164
	165	return ret;
	166	}
	167
	168	SR_PRIV int korad_kaxxxxp_get_value(struct sr_serial_dev_inst *serial,
	169	int target, struct dev_context *devc)
	170	{
	171	int ret, count;
	172	char reply[6];
	173	float *value;
	174	char status_byte;
	175
	176	g_mutex_lock(&devc->rw_mutex);
	177	give_device_time_to_process(devc);
	178
	179	value = NULL;
	180	count = 5;
	181
	182	switch (target) {
	183	case KAXXXXP_CURRENT:
	184	/* Read current from device. */
	185	ret = korad_kaxxxxp_send_cmd(serial, "IOUT1?");
	186	value = &(devc->current);
	187	break;
	188	case KAXXXXP_CURRENT_LIMIT:
	189	/* Read set current from device. */
	190	ret = korad_kaxxxxp_send_cmd(serial, "ISET1?");
	191	value = &(devc->current_limit);
	192	break;
	193	case KAXXXXP_VOLTAGE:
	194	/* Read voltage from device. */
	195	ret = korad_kaxxxxp_send_cmd(serial, "VOUT1?");
	196	value = &(devc->voltage);
	197	break;
	198	case KAXXXXP_VOLTAGE_TARGET:
	199	/* Read set voltage from device. */
	200	ret = korad_kaxxxxp_send_cmd(serial, "VSET1?");
	201	value = &(devc->voltage_target);
	202	break;
	203	case KAXXXXP_STATUS:
	204	case KAXXXXP_OUTPUT:
	205	case KAXXXXP_OCP:
	206	case KAXXXXP_OVP:
	207	/* Read status from device. */
	208	ret = korad_kaxxxxp_send_cmd(serial, "STATUS?");
	209	count = 1;
	210	break;
	211	default:
	212	sr_err("Don't know how to query %d.", target);
	213	g_mutex_unlock(&devc->rw_mutex);
	214	return SR_ERR;
	215	}
	216
	217	devc->req_sent_at = g_get_monotonic_time();
	218
	219	if ((ret = korad_kaxxxxp_read_chars(serial, count, reply)) < 0) {
	220	g_mutex_unlock(&devc->rw_mutex);
	221	return ret;
	222	}
	223
	224	reply[count] = 0;
	225
	226	if (value) {
	227	sr_atof_ascii((const char *)&reply, value);
	228	sr_dbg("value: %f", *value);
	229	} else {
	230	/* We have status reply. */
	231	status_byte = reply[0];
	232	/* Constant current */
	233	devc->cc_mode[0] = !(status_byte & (1 << 0)); /* Channel one */
	234	devc->cc_mode[1] = !(status_byte & (1 << 1)); /* Channel two */
	235	/*
	236	* Tracking
	237	* status_byte & ((1 << 2) \| (1 << 3))
	238	* 00 independent 01 series 11 parallel
	239	*/
	240	devc->beep_enabled = (1 << 4);
	241	devc->ocp_enabled = (status_byte & (1 << 5));
	242	devc->output_enabled = (status_byte & (1 << 6));
	243	/* Velleman LABPS3005 quirk */
	244	if (devc->output_enabled)
	245	devc->ovp_enabled = (status_byte & (1 << 7));
	246	sr_dbg("Status: 0x%02x", status_byte);
	247	sr_spew("Status: CH1: constant %s CH2: constant %s. "
	248	"Tracking would be %s. Device is "
	249	"%s and %s. Buttons are %s. Output is %s "
	250	"and extra bit is %s.",
	251	(status_byte & (1 << 0)) ? "voltage" : "current",
	252	(status_byte & (1 << 1)) ? "voltage" : "current",
	253	(status_byte & (1 << 2)) ? "parallel" : "series",
	254	(status_byte & (1 << 3)) ? "tracking" : "independent",
	255	(status_byte & (1 << 4)) ? "beeping" : "silent",
	256	(status_byte & (1 << 5)) ? "locked" : "unlocked",
	257	(status_byte & (1 << 6)) ? "enabled" : "disabled",
	258	(status_byte & (1 << 7)) ? "true" : "false");
	259	}
	260
	261	/* Read the sixth byte from ISET? BUG workaround. */
	262	if (target == KAXXXXP_CURRENT_LIMIT)
	263	serial_read_blocking(serial, &status_byte, 1, 10);
	264
	265	g_mutex_unlock(&devc->rw_mutex);
	266
	267	return ret;
	268	}
	269
	270	SR_PRIV int korad_kaxxxxp_get_all_values(struct sr_serial_dev_inst *serial,
	271	struct dev_context *devc)
	272	{
	273	int ret, target;
	274
	275	for (target = KAXXXXP_CURRENT;
	276	target <= KAXXXXP_STATUS; target++) {
	277	if ((ret = korad_kaxxxxp_get_value(serial, target, devc)) < 0)
	278	return ret;
	279	}
	280
	281	return ret;
	282	}
	283
	284	static void next_measurement(struct dev_context *devc)
	285	{
	286	switch (devc->acquisition_target) {
	287	case KAXXXXP_CURRENT:
	288	devc->acquisition_target = KAXXXXP_VOLTAGE;
	289	break;
	290	case KAXXXXP_VOLTAGE:
	291	devc->acquisition_target = KAXXXXP_STATUS;
	292	break;
	293	case KAXXXXP_STATUS:
	294	devc->acquisition_target = KAXXXXP_CURRENT;
	295	break;
	296	default:
	297	devc->acquisition_target = KAXXXXP_CURRENT;
	298	sr_err("Invalid target for next acquisition.");
	299	}
	300	}
	301
	302	SR_PRIV int korad_kaxxxxp_receive_data(int fd, int revents, void *cb_data)
	303	{
	304	struct sr_dev_inst *sdi;
	305	struct dev_context *devc;
	306	struct sr_serial_dev_inst *serial;
	307	struct sr_datafeed_packet packet;
	308	struct sr_datafeed_analog analog;
	309	struct sr_analog_encoding encoding;
	310	struct sr_analog_meaning meaning;
	311	struct sr_analog_spec spec;
	312	GSList *l;
	313
	314	(void)fd;
	315	(void)revents;
	316
	317	if (!(sdi = cb_data))
	318	return TRUE;
	319
	320	if (!(devc = sdi->priv))
	321	return TRUE;
	322
	323	serial = sdi->conn;
	324
	325	/* Get the value. */
	326	korad_kaxxxxp_get_value(serial, devc->acquisition_target, devc);
	327
	328	/* Note: digits/spec_digits will be overridden later. */
	329	sr_analog_init(&analog, &encoding, &meaning, &spec, 0);
	330
	331	/* Send the value forward. */
	332	packet.type = SR_DF_ANALOG;
	333	packet.payload = &analog;
	334	analog.num_samples = 1;
	335	l = g_slist_copy(sdi->channels);
	336	if (devc->acquisition_target == KAXXXXP_CURRENT) {
	337	l = g_slist_remove_link(l, g_slist_nth(l, 0));
	338	analog.meaning->channels = l;
	339	analog.meaning->mq = SR_MQ_CURRENT;
	340	analog.meaning->unit = SR_UNIT_AMPERE;
	341	analog.meaning->mqflags = SR_MQFLAG_DC;
	342	analog.encoding->digits = 3;
	343	analog.spec->spec_digits = 3;
	344	analog.data = &devc->current;
	345	sr_session_send(sdi, &packet);
	346	} else if (devc->acquisition_target == KAXXXXP_VOLTAGE) {
	347	l = g_slist_remove_link(l, g_slist_nth(l, 1));
	348	analog.meaning->channels = l;
	349	analog.meaning->mq = SR_MQ_VOLTAGE;
	350	analog.meaning->unit = SR_UNIT_VOLT;
	351	analog.meaning->mqflags = SR_MQFLAG_DC;
	352	analog.encoding->digits = 2;
	353	analog.spec->spec_digits = 2;
	354	analog.data = &devc->voltage;
	355	sr_session_send(sdi, &packet);
	356	sr_sw_limits_update_samples_read(&devc->limits, 1);
	357	}
	358	next_measurement(devc);
	359
	360	if (sr_sw_limits_check(&devc->limits))
	361	sr_dev_acquisition_stop(sdi);
	362
	363	return TRUE;
	364	}