siglent-sds: Drop currently unused switch/case.

[libsigrok.git] / src / hardware / siglent-sds / protocol.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2016 mhooijboer <marchelh@gmail.com>
 * Copyright (C) 2012 Martin Ling <martin-git@earth.li>
 * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
 * Copyright (C) 2013 Mathias Grimmberger <mgri@zaphod.sax.de>
 *
 * 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/>.
 */

#define _GNU_SOURCE

#include <config.h>
#include <errno.h>
#include <glib.h>
#include <math.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
#include "scpi.h"
#include "protocol.h"

/* Set the next event to wait for in siglent_sds_receive(). */
static void siglent_sds_set_wait_event(struct dev_context *devc, enum wait_events event)
{
	if (event == WAIT_STOP) {
		devc->wait_status = 2;
	} else {
		devc->wait_status = 1;
		devc->wait_event = event;
	}
}

/*
 * Waiting for a event will return a timeout after 2 to 3 seconds in order
 * to not block the application.
 */
static int siglent_sds_event_wait(const struct sr_dev_inst *sdi)
{
	char *buf;
	long s;
	int out;
	struct dev_context *devc;
	time_t start;

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

	start = time(NULL);

	s = 10000; /* Sleep time for status refresh. */
	if (devc->wait_status == 1) {
		do {
			if (time(NULL) - start >= 3) {
				sr_dbg("Timeout waiting for trigger.");
				return SR_ERR_TIMEOUT;
			}

			if (sr_scpi_get_string(sdi->conn, ":INR?", &buf) != SR_OK)
				return SR_ERR;
			sr_atoi(buf, &out);
			g_usleep(s);
		} while (out == 0);

		sr_dbg("Device triggered.");

		if ((devc->timebase < 0.51) && (devc->timebase > 0.99e-6)) {
			/*
			 * Timebase * num hor. divs * 85(%) * 1e6(usecs) / 100
			 * -> 85 percent of sweep time
			 */
			s = (devc->timebase * devc->model->series->num_horizontal_divs * 1000);
			sr_spew("Sleeping for %ld usecs after trigger, "
				"to let the acq buffer in the device fill", s);
			g_usleep(s);
		}
	}
	if (devc->wait_status == 2) {
		do {
			if (time(NULL) - start >= 3) {
				sr_dbg("Timeout waiting for trigger.");
				return SR_ERR_TIMEOUT;
			}
			if (sr_scpi_get_string(sdi->conn, ":INR?", &buf) != SR_OK)
				return SR_ERR;
			sr_atoi(buf, &out);
			g_usleep(s);
		/* XXX
		 * Now this loop condition looks suspicious! A bitwise
		 * OR of a variable and a non-zero literal should be
		 * non-zero. Logical AND of several non-zero values
		 * should be non-zero. Are many parts of the condition
		 * not taking effect? Was some different condition meant
		 * to get encoded? This needs review, and adjustment.
		 */
		} while ((out | DEVICE_STATE_TRIG_RDY && out | DEVICE_STATE_DATA_ACQ) && out | DEVICE_STATE_STOPPED);
		sr_dbg("Device triggerd 2.");
		siglent_sds_set_wait_event(devc, WAIT_NONE);
	}

	return SR_OK;
}

static int siglent_sds_trigger_wait(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;

	if (!(devc = sdi->priv))
		return SR_ERR;
	return siglent_sds_event_wait(sdi);
}

/* Wait for scope to got to "Stop" in single shot mode. */
static int siglent_sds_stop_wait(const struct sr_dev_inst *sdi)
{
	return siglent_sds_event_wait(sdi);
}

/* Send a configuration setting. */
SR_PRIV int siglent_sds_config_set(const struct sr_dev_inst *sdi, const char *format, ...)
{
	va_list args;
	int ret;

	va_start(args, format);
	ret = sr_scpi_send_variadic(sdi->conn, format, args);
	va_end(args);

	return ret;
}

/* Start capturing a new frameset. */
SR_PRIV int siglent_sds_capture_start(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;

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

	switch (devc->model->series->protocol) {
	case SPO_MODEL:
		if (devc->data_source == DATA_SOURCE_SCREEN) {
			char *buf;
			int out;

			sr_dbg("Starting data capture for active frameset %" PRIu64 " of %" PRIu64,
				devc->num_frames + 1, devc->limit_frames);
			if (siglent_sds_config_set(sdi, "ARM") != SR_OK)
				return SR_ERR;
			if (sr_scpi_get_string(sdi->conn, ":INR?", &buf) != SR_OK)
				return SR_ERR;
			sr_atoi(buf, &out);
			if (out == DEVICE_STATE_TRIG_RDY) {
				siglent_sds_set_wait_event(devc, WAIT_TRIGGER);
			} else if (out == DEVICE_STATE_TRIG_RDY + 1) {
				sr_spew("Device triggered.");
				siglent_sds_set_wait_event(devc, WAIT_BLOCK);
				return SR_OK;
			} else {
				sr_spew("Device did not enter ARM mode.");
				return SR_ERR;
			}
		} else { /* TODO: Implement history retrieval. */
			unsigned int framecount;
			char buf[200];
			int ret;

			sr_dbg("Starting data capture for history frameset.");
			if (siglent_sds_config_set(sdi, "FPAR?") != SR_OK)
				return SR_ERR;
			ret = sr_scpi_read_data(sdi->conn, buf, 200);
			if (ret < 0) {
				sr_err("Read error while reading data header.");
				return SR_ERR;
			}
			memcpy(&framecount, buf + 40, 4);
			if (devc->limit_frames > framecount)
				sr_err("Frame limit higher than frames in buffer of device!");
			else if (devc->limit_frames == 0)
				devc->limit_frames = framecount;
			sr_dbg("Starting data capture for history frameset %" PRIu64 " of %" PRIu64,
				devc->num_frames + 1, devc->limit_frames);
			if (siglent_sds_config_set(sdi, "FRAM %i", devc->num_frames + 1) != SR_OK)
				return SR_ERR;
			if (siglent_sds_channel_start(sdi) != SR_OK)
				return SR_ERR;
			siglent_sds_set_wait_event(devc, WAIT_STOP);
		}
		break;
	case NON_SPO_MODEL:
		siglent_sds_set_wait_event(devc, WAIT_TRIGGER);
		break;
	}

	return SR_OK;
}

/* Start reading data from the current channel. */
SR_PRIV int siglent_sds_channel_start(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	struct sr_channel *ch;
	const char *s;

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

	ch = devc->channel_entry->data;

	sr_dbg("Starting reading data from channel %d.", ch->index + 1);

	s = (ch->type == SR_CHANNEL_LOGIC) ? "D%d:WF?" : "C%d:WF? ALL";
	if (sr_scpi_send(sdi->conn, s, ch->index + 1) != SR_OK)
		return SR_ERR;
	siglent_sds_set_wait_event(devc, WAIT_NONE);

	siglent_sds_set_wait_event(devc, WAIT_BLOCK);

	devc->num_channel_bytes = 0;
	devc->num_header_bytes = 0;
	devc->num_block_bytes = 0;

	return SR_OK;
}

/* Read the header of a data block. */
static int siglent_sds_read_header(struct sr_dev_inst *sdi)
{
	struct sr_scpi_dev_inst *scpi = sdi->conn;
	struct dev_context *devc = sdi->priv;
	char *buf = (char *)devc->buffer;
	int ret, desc_length;
	int block_offset = 15; /* Offset for descriptor block. */
	long data_length = 0;

	/* Read header from device. */
	ret = sr_scpi_read_data(scpi, buf, SIGLENT_HEADER_SIZE);
	if (ret < SIGLENT_HEADER_SIZE) {
		sr_err("Read error while reading data header.");
		return SR_ERR;
	}
	sr_dbg("Device returned %i bytes.", ret);
	devc->num_header_bytes += ret;
	buf += block_offset; /* Skip to start descriptor block. */

	/* Parse WaveDescriptor header. */
	memcpy(&desc_length, buf + 36, 4); /* Descriptor block length */
	memcpy(&data_length, buf + 60, 4); /* Data block length */

	devc->block_header_size = desc_length + 15;
	devc->num_samples = data_length;

	sr_dbg("Received data block header: '%s' -> block length %d.", buf, ret);

	return ret;
}

SR_PRIV int siglent_sds_receive(int fd, int revents, void *cb_data)
{
	struct sr_dev_inst *sdi;
	struct sr_scpi_dev_inst *scpi;
	struct dev_context *devc;
	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 sr_datafeed_logic logic;
	int len, i;
	struct sr_channel *ch;

	(void)fd;

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

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

	scpi = sdi->conn;

	if (!(revents == G_IO_IN || revents == 0))
		return TRUE;

	switch (devc->wait_event) {
	case WAIT_NONE:
		break;
	case WAIT_TRIGGER:
		if (siglent_sds_trigger_wait(sdi) != SR_OK)
			return TRUE;
		if (siglent_sds_channel_start(sdi) != SR_OK)
			return TRUE;
		return TRUE;
	case WAIT_BLOCK:
		if (siglent_sds_channel_start(sdi) != SR_OK)
			return TRUE;
		break;
	case WAIT_STOP:
		if (siglent_sds_stop_wait(sdi) != SR_OK)
			return TRUE;
		if (siglent_sds_channel_start(sdi) != SR_OK)
			return TRUE;
		return TRUE;
	default:
		sr_err("BUG: Unknown event target encountered.");
		break;
	}
	ch = devc->channel_entry->data;
	len = 0;

	if (devc->num_block_bytes == 0) {
		if (devc->memory_depth >= 14000000) {
			sr_err("Device memory depth is set to 14Mpts, so please be patient.");
			g_usleep(4900000); /* Sleep for large memory set. */
		}
		if (sr_scpi_read_begin(scpi) != SR_OK)
			return TRUE;
		sr_dbg("New block header expected.");
		len = siglent_sds_read_header(sdi);
		if (len == 0)
			/* Still reading the header. */
			return TRUE;
		if (len == -1) {
			sr_err("Read error, aborting capture.");
			packet.type = SR_DF_FRAME_END;
			sr_session_send(sdi, &packet);
			sdi->driver->dev_acquisition_stop(sdi);
			return TRUE;
		}
		devc->num_block_bytes = 0;
		devc->num_block_read = 0;
	}

	if (len == -1) {
		sr_err("Read error, aborting capture.");
		packet.type = SR_DF_FRAME_END;
		sr_session_send(sdi, &packet);
		sdi->driver->dev_acquisition_stop(sdi);
		return TRUE;
	}

	while (devc->num_block_bytes < devc->num_samples) {
		len = sr_scpi_read_data(scpi, (char *)devc->buffer, devc->num_samples);
		if (len == -1) {
			sr_err("Read error, aborting capture.");
			packet.type = SR_DF_FRAME_END;
			sr_session_send(sdi, &packet);
			sdi->driver->dev_acquisition_stop(sdi);
			return TRUE;
		}
		devc->num_block_read += 1;
		devc->num_block_bytes += len;
		if (devc->num_block_bytes >= devc->num_samples ) {
			/* Offset the data block buffer past the IEEE header and description header. */
			devc->buffer += devc->block_header_size;
			len = devc->num_samples;
		}
		sr_dbg("Received block: %i, %d bytes.", devc->num_block_read, len);
		if (ch->type == SR_CHANNEL_ANALOG) {
			float vdiv = devc->vdiv[ch->index];
			float offset = devc->vert_offset[ch->index];
			GArray *float_data;
			static GArray *data;
			float voltage, vdivlog;
			int digits;

			data = g_array_sized_new(FALSE, FALSE, sizeof(uint8_t), len);
			g_array_append_vals(data, devc->buffer, len);
			float_data = g_array_new(FALSE, FALSE, sizeof(float));
			for (i = 0; i < len; i++) {
				voltage = (float)g_array_index(data, int8_t, i) / 25;
				voltage = ((vdiv * voltage) - offset);
				g_array_append_val(float_data, voltage);
			}
			vdivlog = log10f(vdiv);
			digits = -(int) vdivlog + (vdivlog < 0.0);
			sr_analog_init(&analog, &encoding, &meaning, &spec, digits);
			analog.meaning->channels = g_slist_append(NULL, ch);
			analog.num_samples = float_data->len;
			analog.data = (float *)float_data->data;
			analog.meaning->mq = SR_MQ_VOLTAGE;
			analog.meaning->unit = SR_UNIT_VOLT;
			analog.meaning->mqflags = 0;
			packet.type = SR_DF_ANALOG;
			packet.payload = &analog;
			sr_session_send(sdi, &packet);
			g_slist_free(analog.meaning->channels);
			g_array_free(data, TRUE);
		} else {
			logic.length = len;
			logic.unitsize = 1;
			logic.data = devc->buffer;
			packet.type = SR_DF_LOGIC;
			packet.payload = &logic;
			sr_session_send(sdi, &packet);
		}

		if (devc->num_samples == devc->num_block_bytes) {
			sr_dbg("Transfer has been completed.");
			devc->num_header_bytes = 0;
			devc->num_block_bytes = 0;
			if (!sr_scpi_read_complete(scpi)) {
				sr_err("Read should have been completed.");
				packet.type = SR_DF_FRAME_END;
				sr_session_send(sdi, &packet);
				sdi->driver->dev_acquisition_stop(sdi);
				return TRUE;
			}
			devc->num_block_read = 0;
		} else {
			sr_dbg("%" PRIu64 " of %" PRIu64 " block bytes read.",
				devc->num_block_bytes, devc->num_samples);
		}
	}

	if (devc->channel_entry->next) {
		/* We got the frame for this channel, now get the next channel. */
		devc->channel_entry = devc->channel_entry->next;
		siglent_sds_channel_start(sdi);
	} else {
		/* Done with this frame. */
		packet.type = SR_DF_FRAME_END;
		sr_session_send(sdi, &packet);

		if (++devc->num_frames == devc->limit_frames) {
			/* Last frame, stop capture. */
			sdi->driver->dev_acquisition_stop(sdi);
		} else {
			/* Get the next frame, starting with the first channel. */
			devc->channel_entry = devc->enabled_channels;
			siglent_sds_capture_start(sdi);

			/* Start of next frame. */
			packet.type = SR_DF_FRAME_BEGIN;
			sr_session_send(sdi, &packet);
		}
	}

	return TRUE;
}

SR_PRIV int siglent_sds_get_dev_cfg(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	struct sr_channel *ch;
	char *cmd, *response;
	unsigned int i;
	int res, num_tokens;
	gchar **tokens;
        int len;
        float trigger_pos;

	devc = sdi->priv;

	/* Analog channel state. */
	for (i = 0; i < devc->model->analog_channels; i++) {
		cmd = g_strdup_printf("C%i:TRA?", i + 1);
		res = sr_scpi_get_bool(sdi->conn, cmd, &devc->analog_channels[i]);
		g_free(cmd);
		if (res != SR_OK)
			return SR_ERR;
		ch = g_slist_nth_data(sdi->channels, i);
		ch->enabled = devc->analog_channels[i];
	}
	sr_dbg("Current analog channel state:");
	for (i = 0; i < devc->model->analog_channels; i++)
		sr_dbg("CH%d %s", i + 1, devc->analog_channels[i] ? "On" : "Off");

	/* Digital channel state. */
	if (devc->model->has_digital) {
		gboolean status;

		sr_dbg("Check logic analyzer channel state.");
		devc->la_enabled = FALSE;
		cmd = g_strdup_printf("DGST?");
		res = sr_scpi_get_bool(sdi->conn, cmd, &status);
		g_free(cmd);
		if (res != SR_OK)
			return SR_ERR;
		sr_dbg("Logic analyzer status: %s", status ? "On" : "Off");
		if (status) {
			devc->la_enabled = TRUE;
			for (i = 0; i < ARRAY_SIZE(devc->digital_channels); i++) {
				cmd = g_strdup_printf("D%i:DGCH?", i);
				res = sr_scpi_get_bool(sdi->conn, cmd, &devc->digital_channels[i]);
				g_free(cmd);
				if (res != SR_OK)
					return SR_ERR;
				ch = g_slist_nth_data(sdi->channels, i + devc->model->analog_channels);
				ch->enabled = devc->digital_channels[i];
				sr_dbg("D%d: %s", i, devc->digital_channels[i] ? "On" : "Off");
			}
		} else {
			for (i = 0; i < ARRAY_SIZE(devc->digital_channels); i++) {
				ch = g_slist_nth_data(sdi->channels, i + devc->model->analog_channels);
				devc->digital_channels[i] = FALSE;
				ch->enabled = devc->digital_channels[i];
				sr_dbg("D%d: %s", i, devc->digital_channels[i] ? "On" : "Off");
			}
		}
	}

	/* Timebase. */
	if (sr_scpi_get_float(sdi->conn, ":TDIV?", &devc->timebase) != SR_OK)
		return SR_ERR;
	sr_dbg("Current timebase: %g.", devc->timebase);

	/* Probe attenuation. */
	for (i = 0; i < devc->model->analog_channels; i++) {
		cmd = g_strdup_printf("C%d:ATTN?", i + 1);
		res = sr_scpi_get_float(sdi->conn, cmd, &devc->attenuation[i]);
		g_free(cmd);
		if (res != SR_OK)
			return SR_ERR;
	}
	sr_dbg("Current probe attenuation:");
	for (i = 0; i < devc->model->analog_channels; i++)
		sr_dbg("CH%d %g", i + 1, devc->attenuation[i]);

	/* Vertical gain and offset. */
	if (siglent_sds_get_dev_cfg_vertical(sdi) != SR_OK)
		return SR_ERR;

	/* Coupling. */
	for (i = 0; i < devc->model->analog_channels; i++) {
		cmd = g_strdup_printf("C%d:CPL?", i + 1);
		res = sr_scpi_get_string(sdi->conn, cmd, &devc->coupling[i]);
		g_free(cmd);
		if (res != SR_OK)
			return SR_ERR;
	}

	sr_dbg("Current coupling:");
	for (i = 0; i < devc->model->analog_channels; i++)
		sr_dbg("CH%d %s", i + 1, devc->coupling[i]);

	/* Trigger source. */
	response = NULL;
	tokens = NULL;
	if (sr_scpi_get_string(sdi->conn, "TRSE?", &response) != SR_OK)
		return SR_ERR;
	tokens = g_strsplit(response, ",", 0);
	for (num_tokens = 0; tokens[num_tokens] != NULL; num_tokens++);
	if (num_tokens < 4) {
		sr_dbg("IDN response not according to spec: %80.s.", response);
		g_strfreev(tokens);
		g_free(response);
		return SR_ERR_DATA;
	}
	g_free(response);
	devc->trigger_source = g_strstrip(g_strdup(tokens[2]));
	sr_dbg("Current trigger source: %s.", devc->trigger_source);

	/* TODO: Horizontal trigger position. */
	response = "";
	trigger_pos = 0;
	if (sr_scpi_get_string(sdi->conn, g_strdup_printf("%s:TRDL?", devc->trigger_source), &response) != SR_OK)
		return SR_ERR;
	len = strlen(response);
	if (!g_ascii_strcasecmp(response + (len - 2), "us")) {
		trigger_pos = atof(response) / SR_GHZ(1);
		sr_dbg("Current trigger position us %s.", response);
	} else if (!g_ascii_strcasecmp(response + (len - 2), "ns")) {
		trigger_pos = atof(response) / SR_MHZ(1);
		sr_dbg("Current trigger position ms %s.", response);
	} else if (!g_ascii_strcasecmp(response + (len - 2), "ms")) {
		trigger_pos = atof(response) / SR_KHZ(1);
		sr_dbg("Current trigger position ns %s.", response);
	} else if (!g_ascii_strcasecmp(response + (len - 2), "s")) {
		trigger_pos = atof(response);
		sr_dbg("Current trigger position s %s.", response);
	};
	devc->horiz_triggerpos = trigger_pos;

	sr_dbg("Current horizontal trigger position %.10f", devc->horiz_triggerpos);

	/* Trigger slope. */
	cmd = g_strdup_printf("%s:TRSL?", devc->trigger_source);
	res = sr_scpi_get_string(sdi->conn, cmd, &devc->trigger_slope);
	g_free(cmd);
	if (res != SR_OK)
		return SR_ERR;
	sr_dbg("Current trigger slope: %s.", devc->trigger_slope);

	/* Trigger level. */
	cmd = g_strdup_printf("%s:TRLV?", devc->trigger_source);
	res = sr_scpi_get_float(sdi->conn, cmd, &devc->trigger_level);
	g_free(cmd);
	if (res != SR_OK)
		return SR_ERR;
	sr_dbg("Current trigger level: %g.", devc->trigger_level);
	return SR_OK;
}

SR_PRIV int siglent_sds_get_dev_cfg_vertical(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	char *cmd;
	unsigned int i;
	int res;

	devc = sdi->priv;

	/* Vertical gain. */
	for (i = 0; i < devc->model->analog_channels; i++) {
		cmd = g_strdup_printf("C%d:VDIV?", i + 1);
		res = sr_scpi_get_float(sdi->conn, cmd, &devc->vdiv[i]);
		g_free(cmd);
		if (res != SR_OK)
			return SR_ERR;
	}
	sr_dbg("Current vertical gain:");
	for (i = 0; i < devc->model->analog_channels; i++)
		sr_dbg("CH%d %g", i + 1, devc->vdiv[i]);

	/* Vertical offset. */
	for (i = 0; i < devc->model->analog_channels; i++) {
		cmd = g_strdup_printf("C%d:OFST?", i + 1);
		res = sr_scpi_get_float(sdi->conn, cmd, &devc->vert_offset[i]);
		g_free(cmd);
		if (res != SR_OK)
			return SR_ERR;
	}
	sr_dbg("Current vertical offset:");
	for (i = 0; i < devc->model->analog_channels; i++)
		sr_dbg("CH%d %g", i + 1, devc->vert_offset[i]);

	return SR_OK;
}

SR_PRIV int siglent_sds_get_dev_cfg_horizontal(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	char *cmd;
	int res;
	char *sample_points_string;
	float samplerate_scope, fvalue;

	devc = sdi->priv;
	cmd = g_strdup_printf("SANU? C1");
	res = sr_scpi_get_string(sdi->conn, cmd, &sample_points_string);
	g_free(cmd);
	samplerate_scope = 0;
	fvalue = 0;
	if (res != SR_OK)
		return SR_ERR;

	if (g_strstr_len(sample_points_string, -1, "Mpts") != NULL) {
		sample_points_string[strlen(sample_points_string) -4] = '\0';
		if (sr_atof_ascii(sample_points_string, &fvalue) != SR_OK) {
			sr_dbg("Invalid float converted from scope response.");
			return SR_ERR;
		}
		samplerate_scope = fvalue * 1000000;
	} else if (g_strstr_len(sample_points_string, -1, "Kpts") != NULL){
		sample_points_string[strlen(sample_points_string) -4] = '\0';
		if (sr_atof_ascii(sample_points_string, &fvalue) != SR_OK) {
			sr_dbg("Invalid float converted from scope response.");
			return SR_ERR;
		}
		samplerate_scope = fvalue * 10000;
	} else {
		samplerate_scope = fvalue;
	}
	g_free(sample_points_string);
	/* Get the timebase. */
	if (sr_scpi_get_float(sdi->conn, ":TDIV?", &devc->timebase) != SR_OK)
		return SR_ERR;
	sr_dbg("Current timebase: %g.", devc->timebase);
	devc->samplerate = samplerate_scope / (devc->timebase * devc->model->series->num_horizontal_divs);
	devc->memory_depth = samplerate_scope;
	return SR_OK;
}