hp-3457a: Implement basic configuration and sampling

KNOWN ISSUES:
- When sampling with 100 NPLC, the poll function will timeout a few
times before the first sample is acquired. Increasing the timeout
passed to sr_scpi_source_add() will cause all the other commands to
be processed slowly, producing a sampling rate of about one sample
every ten seconds.
- Support for plug-in cards (44491A and 44492A) is not implemented.
- Support for AC, AC+DC and four-wire resistance measurements is not
implemented.
- Support for configuring the frequency measurement source is not
implemented.

src/hardware/hp-3457a/api.c

@@ -18,10 +18,121 @@
  */
 
 #include <config.h>
+#include <scpi.h>
+#include <string.h>
 #include "protocol.h"
 
+static const uint32_t scanopts[] = {
+	SR_CONF_CONN,
+};
+
+static const uint32_t drvopts[] = {
+	SR_CONF_MULTIMETER,
+};
+
+static const uint32_t devopts[] = {
+	SR_CONF_CONTINUOUS | SR_CONF_SET,
+	SR_CONF_LIMIT_SAMPLES | SR_CONF_SET,
+	SR_CONF_MEASURED_QUANTITY | SR_CONF_SET,
+	SR_CONF_ADC_POWERLINE_CYCLES | SR_CONF_SET | SR_CONF_GET,
+};
+
 SR_PRIV struct sr_dev_driver hp_3457a_driver_info;
 
+static int create_front_channel(struct sr_dev_inst *sdi, int chan_idx)
+{
+	struct sr_channel *channel;
+	struct sr_channel_group *front;
+
+	channel = sr_channel_new(sdi, chan_idx++, SR_CHANNEL_ANALOG,
+				 TRUE, "Front");
+
+	front = g_malloc0(sizeof(*front));
+	front->name = g_strdup("Front");
+	front->channels = g_slist_append(front->channels, channel);
+	sdi->channel_groups = g_slist_append(sdi->channel_groups, front);
+
+	return chan_idx;
+}
+
+static int create_rear_channels(struct sr_dev_inst *sdi, int chan_idx,
+				 const struct rear_card_info *card)
+{
+	(void) sdi;
+
+	/* When card is NULL, we couldn't identify the type of card. */
+	if (!card)
+		return chan_idx;
+
+	/* TODO: Create channel descriptor for plug-in cards here. */
+	return chan_idx;
+}
+
+static gchar *get_revision(struct sr_scpi_dev_inst *scpi)
+{
+	int ret, major, minor;
+	GArray *rev_numbers;
+
+	/* Report a version of '0.0' if we can't parse the response. */
+	major = minor = 0;
+
+	ret = sr_scpi_get_floatv(scpi, "REV?", &rev_numbers);
+	if ((ret == SR_OK) && (rev_numbers->len >= 2)) {
+		major = (int)g_array_index(rev_numbers, float, 0);
+		minor = (int)g_array_index(rev_numbers, float, 1);
+	}
+
+	g_array_free(rev_numbers, TRUE);
+
+	return g_strdup_printf("%d.%d", major, minor);
+}
+
+static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
+{
+	int ret, idx;
+	char *response;
+	struct sr_dev_inst *sdi;
+	struct dev_context *devc;
+
+	/*
+	 * This command ensures we receive an EOI after every response, so that
+	 * we don't wait the entire timeout after the response is received.
+	 */
+	if (sr_scpi_send(scpi, "END ALWAYS") != SR_OK)
+		return NULL;
+
+	ret = sr_scpi_get_string(scpi, "ID?", &response);
+	if ((ret != SR_OK) || !response)
+		return NULL;
+
+	if (strcmp(response, "HP3457A"))
+		return NULL;
+
+	g_free(response);
+
+	devc = g_malloc0(sizeof(struct dev_context));
+	sdi = g_malloc0(sizeof(struct sr_dev_inst));
+	sdi->vendor = g_strdup("Hewlett-Packard");
+	sdi->model = g_strdup("3457A");
+	sdi->version = get_revision(scpi);
+	sdi->conn = scpi;
+	sdi->driver = &hp_3457a_driver_info;
+	sdi->inst_type = SR_INST_SCPI;
+	sdi->priv = devc;
+
+	/* There is no way to probe the measurement mode. It must be set. */
+	devc->measurement_mq = 0;
+	devc->measurement_unit = 0;
+
+	/* Probe rear card option and create channels accordingly (TODO). */
+	devc->rear_card = hp_3457a_probe_rear_card(scpi);
+	idx = 0;
+	idx = create_front_channel(sdi, idx);
+	create_rear_channels(sdi, idx, devc->rear_card);
+
+	return sdi;
+}
+
 static int init(struct sr_dev_driver *di, struct sr_context *sr_ctx)
 {
 	return std_init(sr_ctx, di, LOG_PREFIX);
@@ -29,19 +140,7 @@ static int init(struct sr_dev_driver *di, struct sr_context *sr_ctx)
 
 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 {
-	struct drv_context *drvc;
+	return sr_scpi_scan(di->context, options, probe_device);
-	GSList *devices;
-
-	(void)options;
-
-	devices = NULL;
-	drvc = di->context;
-	drvc->instances = NULL;
-
-	/* TODO: scan for devices, either based on a SR_CONF_CONN option
-	 * or on a USB scan. */
-
-	return devices;
 }
 
 static GSList *dev_list(const struct sr_dev_driver *di)
@@ -54,11 +153,39 @@ static int dev_clear(const struct sr_dev_driver *di)
 	return std_dev_clear(di, NULL);
 }
 
+/*
+ * We need to set the HP 3457A to a known state, and there are quite a number
+ * of knobs to tweak. Here's a brief explanation of what's going on. For more
+ * details, print out and consult the user manual.
+ *   PRESET
+ *     Set the instrument to a pre-determined state. This is easier and faster
+ *     than sending a few dozen commands. Some of the PRESET defaults include
+ *     ASCII output format, and synchronous triggering. See user manual for
+ *     more details.
+ *
+ * After the PRESET command, the instrument is in a known state, and only those
+ * parameters for which the default is unsuitable are modified:
+ *   INBUF ON
+ *     Enable the HP-IB input buffer. This allows the instrument to release the
+ *     HP-IB bus before processing the command, and increases throughput on
+ *     GPIB buses with more than one device.
+ *   TRIG HOLD
+ *     Do not trigger new measurements until instructed to do so.
+ */
 static int dev_open(struct sr_dev_inst *sdi)
 {
-	(void)sdi;
+	struct sr_scpi_dev_inst *scpi = sdi->conn;
+	struct dev_context *devc;
 
-	/* TODO: get handle from sdi->conn and open it. */
+	if (sr_scpi_open(scpi) != SR_OK)
+		return SR_ERR;
+
+	devc=sdi->priv;
+
+	sr_scpi_send(scpi, "PRESET");
+	sr_scpi_send(scpi, "INBUF ON");
+	sr_scpi_send(scpi, "TRIG HOLD");
+	sr_scpi_get_float(scpi, "NPLC?", &devc->nplc);
 
 	sdi->status = SR_ST_ACTIVE;
 
@@ -67,9 +194,15 @@ static int dev_open(struct sr_dev_inst *sdi)
 
 static int dev_close(struct sr_dev_inst *sdi)
 {
-	(void)sdi;
+	struct sr_scpi_dev_inst *scpi = sdi->conn;
 
-	/* TODO: get handle from sdi->conn and close it. */
+	if (sdi->status != SR_ST_ACTIVE)
+		return SR_ERR_DEV_CLOSED;
+
+	/* Switch back to auto-triggering. */
+	sr_scpi_send(scpi, "TRIG AUTO");
+
+	sr_scpi_close(scpi);
 
 	sdi->status = SR_ST_INACTIVE;
 
@@ -78,25 +211,24 @@ static int dev_close(struct sr_dev_inst *sdi)
 
 static int cleanup(const struct sr_dev_driver *di)
 {
-	dev_clear(di);
+	return dev_clear(di);
-
-	/* TODO: free other driver resources, if any. */
-
-	return SR_OK;
 }
 
 static int config_get(uint32_t key, GVariant **data,
 	const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
 {
 	int ret;
+	struct dev_context *devc;
 
-	(void)sdi;
-	(void)data;
 	(void)cg;
 
+	devc = sdi->priv;
+
 	ret = SR_OK;
 	switch (key) {
-	/* TODO */
+	case SR_CONF_ADC_POWERLINE_CYCLES:
+		*data = g_variant_new_double(devc->nplc);
+		break;
 	default:
 		return SR_ERR_NA;
 	}
@@ -105,19 +237,35 @@ static int config_get(uint32_t key, GVariant **data,
 }
 
 static int config_set(uint32_t key, GVariant *data,
-	const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
+		      const struct sr_dev_inst *sdi,
+		      const struct sr_channel_group *cg)
 {
 	int ret;
+	enum sr_mq mq;
+	struct dev_context *devc;
+	GVariant *tuple_child;
 
-	(void)data;
 	(void)cg;
 
 	if (sdi->status != SR_ST_ACTIVE)
 		return SR_ERR_DEV_CLOSED;
 
+	devc = sdi->priv;
+
 	ret = SR_OK;
 	switch (key) {
-	/* TODO */
+	case SR_CONF_LIMIT_SAMPLES:
+		devc->limit_samples = g_variant_get_uint64(data);
+		break;
+	case SR_CONF_MEASURED_QUANTITY:
+		tuple_child = g_variant_get_child_value(data, 0);
+		mq = g_variant_get_uint32(tuple_child);
+		ret = hp_3457a_set_mq(sdi, mq);
+		g_variant_unref(tuple_child);
+		break;
+	case SR_CONF_ADC_POWERLINE_CYCLES:
+		ret = hp_3457a_set_nplc(sdi, g_variant_get_double(data));
+		break;
 	default:
 		ret = SR_ERR_NA;
 	}
@@ -130,30 +278,72 @@ static int config_list(uint32_t key, GVariant **data,
 {
 	int ret;
 
-	(void)sdi;
+	if (key == SR_CONF_SCAN_OPTIONS) {
-	(void)data;
+		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
-	(void)cg;
+			scanopts, ARRAY_SIZE(scanopts), sizeof(uint32_t));
+		return SR_OK;
+	} else if ((key == SR_CONF_DEVICE_OPTIONS) && !sdi) {
+		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
+			drvopts, ARRAY_SIZE(drvopts), sizeof(uint32_t));
+		return SR_OK;
+	} else if ((key == SR_CONF_DEVICE_OPTIONS) && !cg) {
+		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
+			devopts, ARRAY_SIZE(devopts), sizeof(uint32_t));
+		return SR_OK;
+	}
+
+	/* From here on, we're only concerned with channel group config. */
+	if (!cg)
+		return SR_ERR_NA;
+
+	/*
+	 * TODO: Implement channel group configuration when adding support for
+	 * plug-in cards.
+	 */
 
 	ret = SR_OK;
 	switch (key) {
-	/* TODO */
 	default:
-		return SR_ERR_NA;
+		ret = SR_ERR_NA;
 	}
 
 	return ret;
 }
 
+/*
+ * TRIG SGL
+ *   Trigger the first measurement, then hold. We can't let the instrument
+ *   auto-trigger because we read several registers to make a complete
+ *   reading. If the instrument were auto-triggering, we could get the
+ *   reading for sample N, but a new measurement is made and when we read the
+ *   HIRES register, it contains data for sample N+1. This would produce
+ *   wrong readings.
+ */
 static int dev_acquisition_start(const struct sr_dev_inst *sdi, void *cb_data)
 {
-	(void)sdi;
+	int ret;
+	struct sr_scpi_dev_inst *scpi;
+	struct dev_context *devc;
+
 	(void)cb_data;
 
 	if (sdi->status != SR_ST_ACTIVE)
 		return SR_ERR_DEV_CLOSED;
 
-	/* TODO: configure hardware, reset acquisition state, set up
+	scpi = sdi->conn;
-	 * callbacks and send header packet. */
+	devc = sdi->priv;
+
+	ret = sr_scpi_source_add(sdi->session, scpi, G_IO_IN, 100,
+				 hp_3457a_receive_data, (void *)sdi);
+	if (ret != SR_OK)
+		return ret;
+
+	std_session_send_df_header(sdi, LOG_PREFIX);
+
+	/* Start first measurement. */
+	sr_scpi_send(scpi, "TRIG SGL");
+	devc->acq_state = ACQ_TRIGGERED_MEASUREMENT;
+	devc->num_samples = 0;
 
 	return SR_OK;
 }
@@ -165,8 +355,6 @@ static int dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
 	if (sdi->status != SR_ST_ACTIVE)
 		return SR_ERR_DEV_CLOSED;
 
-	/* TODO: stop acquisition. */
-
 	return SR_OK;
 }
 

src/hardware/hp-3457a/protocol.c

@@ -18,14 +18,251 @@
  */
 
 #include <config.h>
+#include <math.h>
+#include <scpi.h>
 #include "protocol.h"
 
+/*
+ * Currently, only DC voltage and current are supported, as switching to AC or
+ * AC+DC requires mq flags, which is not yet implemented.
+ * Four-wire resistance measurements are not implemented (See "OHMF" command).
+ * The source for the frequency measurement can be either AC voltage, AC+DC
+ * voltage, AC current, or AC+DC current. Configuring this is not yet
+ * supported. For details, see "FSOURCE" command.
+ */
+static const struct {
+	enum sr_mq mq;
+	enum sr_unit unit;
+	const char *cmd;
+} sr_mq_to_cmd_map[] = {
+	{ SR_MQ_VOLTAGE, SR_UNIT_VOLT, "DCV" },
+	{ SR_MQ_CURRENT, SR_UNIT_AMPERE, "DCI" },
+	{ SR_MQ_RESISTANCE, SR_UNIT_OHM, "OHM" },
+	{ SR_MQ_FREQUENCY, SR_UNIT_HERTZ, "FREQ" },
+};
+
+static const struct rear_card_info rear_card_parameters[] = {
+	{
+		.type = REAR_TERMINALS,
+		.card_id = 0,
+		.name = "Rear terminals",
+		.cg_name = "rear",
+	}, {
+		.type = HP_44491A,
+		.card_id = 44491,
+		.name = "44491A Armature Relay Multiplexer",
+		.cg_name = "44491a",
+	}, {
+		.type = HP_44492A,
+		.card_id = 44492,
+		.name = "44492A Reed Relay Multiplexer",
+		.cg_name = "44492a",
+	}
+};
+
+SR_PRIV int hp_3457a_set_mq(const struct sr_dev_inst *sdi, enum sr_mq mq)
+{
+	int ret;
+	size_t i;
+	struct sr_scpi_dev_inst *scpi = sdi->conn;
+	struct dev_context *devc = sdi->priv;
+
+	for (i = 0; i < ARRAY_SIZE(sr_mq_to_cmd_map); i++) {
+		if (sr_mq_to_cmd_map[i].mq != mq)
+			continue;
+		ret = sr_scpi_send(scpi, sr_mq_to_cmd_map[i].cmd);
+		if (ret == SR_OK) {
+			devc->measurement_mq = sr_mq_to_cmd_map[i].mq;
+			devc->measurement_unit = sr_mq_to_cmd_map[i].unit;
+		}
+		return ret;
+	}
+
+	return SR_ERR_NA;
+}
+
+SR_PRIV const struct rear_card_info *hp_3457a_probe_rear_card(struct sr_scpi_dev_inst *scpi)
+{
+	size_t i;
+	float card_fval;
+	unsigned int card_id;
+	const struct rear_card_info *rear_card = NULL;
+
+	if (sr_scpi_get_float(scpi, "OPT?", &card_fval) != SR_OK)
+		return NULL;
+
+	card_id = (unsigned int)card_fval;
+
+	for (i = 0; i < ARRAY_SIZE(rear_card_parameters); i++) {
+		if (rear_card_parameters[i].card_id == card_id) {
+			rear_card = rear_card_parameters + i;
+			break;
+		}
+	}
+
+	if (!rear_card)
+		return NULL;
+
+	sr_info("Found %s.", rear_card->name);
+
+	return rear_card;
+}
+
+SR_PRIV int hp_3457a_set_nplc(const struct sr_dev_inst *sdi, float nplc)
+{
+	int ret;
+	struct sr_scpi_dev_inst *scpi = sdi->conn;
+	struct dev_context *devc = sdi->priv;
+
+	if ((nplc < 1E-6) || (nplc > 100))
+		return SR_ERR_ARG;
+
+	/* Only need one digit of precision here. */
+	ret = sr_scpi_send(scpi, "NPLC %.0E", nplc);
+
+	/*
+	 * The instrument only has a few valid NPLC setting, so get back the
+	 * one which was selected.
+	 */
+	sr_scpi_get_float(scpi, "NPLC?", &devc->nplc);
+
+	return ret;
+}
+
+/* HIRES register only contains valid data with 10 or more powerline cycles. */
+static int is_highres_enabled(struct dev_context *devc)
+{
+	return (devc->nplc >= 10.0);
+}
+
+static void retrigger_measurement(struct sr_scpi_dev_inst *scpi,
+				  struct dev_context *devc)
+{
+	sr_scpi_send(scpi, "?");
+	devc->acq_state = ACQ_TRIGGERED_MEASUREMENT;
+}
+
+static void request_hires(struct sr_scpi_dev_inst *scpi,
+			  struct dev_context *devc)
+{
+	sr_scpi_send(scpi, "RMATH HIRES");
+	devc->acq_state = ACQ_REQUESTED_HIRES;
+}
+
+static void request_range(struct sr_scpi_dev_inst *scpi,
+			  struct dev_context *devc)
+{
+	sr_scpi_send(scpi, "RANGE?");
+	devc->acq_state = ACQ_REQUESTED_RANGE;
+}
+
+/*
+ * Calculate the number of leading zeroes in the measurement.
+ *
+ * Depending on the range and measurement, a reading may not have eight digits
+ * of resolution. For example, on a 30V range:
+ *    : 10.000000 V has 8 significant digits
+ *    :  9.999999 V has 7 significant digits
+ *    :  0.999999 V has 6 significant digits
+ *
+ * The number of significant digits is determined based on the range in which
+ * the measurement was taken:
+ *    1. By taking the base 10 logarithm of the range, and converting that to
+ *       an integer, we can get the minimum reading which has a full resolution
+ *       reading. Raising 10 to the integer power gives the full resolution.
+ *       Ex: For 30 V range, a full resolution reading is 10.000000.
+ *    2. A ratio is taken between the full resolution reading and the
+ *       measurement. Since the full resolution reading is a power of 10,
+ *       for every leading zero, this ratio will be slightly higher than a
+ *       power of 10. For example, for 10 V full resolution:
+ *          : 10.000000 V, ratio = 1.0000000
+ *          :  9.999999 V, ratio = 1.0000001
+ *          :  0.999999 V, ratio = 10.000001
+ *    3. The ratio is rounded up to prevent loss of precision in the next step.
+ *    4. The base 10 logarithm of the ratio is taken, then rounded up. This
+ *       gives the number of leading zeroes in the measurement.
+ *       For example, for 10 V full resolution:
+ *          : 10.000000 V, ceil(1.0000000) =  1, log10 = 0.00; 0 leading zeroes
+ *          :  9.999999 V, ceil(1.0000001) =  2, log10 = 0.30; 1 leading zero
+ *          :  0.999999 V, ceil(10.000001) = 11, log10 = 1.04, 2 leading zeroes
+ *    5. The number of leading zeroes is subtracted from the maximum number of
+ *       significant digits, 8, at 7 1/2 digits resolution.
+ *       For a 10 V full resolution reading, this gives:
+ *          : 10.000000 V, 0 leading zeroes => 8 significant digits
+ *          :  9.999999 V, 1 leading zero   => 7 significant digits
+ *          :  0.999999 V, 2 leading zeroes => 6 significant digits
+ *
+ * Single precision floating point numbers can achieve about 16 million counts,
+ * but in high resolution mode we can get as much as 30 million counts. As a
+ * result, these calculations must be done with double precision
+ * (the HP 3457A is a very precise instrument).
+ */
+static int calculate_num_zero_digits(double measurement, double range)
+{
+	int zero_digits;
+	double min_full_res_reading, log10_range, full_res_ratio;
+
+	log10_range = log10(range);
+	min_full_res_reading = pow(10, (int)log10_range);
+	if (measurement > min_full_res_reading) {
+		zero_digits = 0;
+	} else if (measurement == 0.0) {
+		zero_digits = 0;
+	} else {
+		full_res_ratio = min_full_res_reading / measurement;
+		zero_digits = ceil(log10(ceil(full_res_ratio)));
+	}
+
+	return zero_digits;
+}
+
+static void acq_send_measurement(struct sr_dev_inst *sdi)
+{
+	double hires_measurement;
+	int zero_digits, num_digits;
+	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 = sdi->priv;
+
+	hires_measurement = devc->base_measurement;
+	if (is_highres_enabled(devc))
+		hires_measurement += devc->hires_register;
+
+	/* Figure out how many of the digits are significant. */
+	num_digits = is_highres_enabled(devc) ? 8 : 7;
+	zero_digits = calculate_num_zero_digits(hires_measurement,
+						devc->measurement_range);
+	num_digits = num_digits - zero_digits;
+
+	packet.type = SR_DF_ANALOG;
+	packet.payload = &analog;
+
+	sr_analog_init(&analog, &encoding, &meaning, &spec, num_digits);
+	encoding.unitsize = sizeof(double);
+
+	meaning.channels = sdi->channels;
+
+	analog.num_samples = 1;
+	analog.data = &hires_measurement;
+
+	meaning.mq = devc->measurement_mq;
+	meaning.unit = devc->measurement_unit;
+
+	sr_session_send(sdi, &packet);
+}
+
 SR_PRIV int hp_3457a_receive_data(int fd, int revents, void *cb_data)
 {
-	const struct sr_dev_inst *sdi;
+	int ret;
+	struct sr_scpi_dev_inst *scpi;
 	struct dev_context *devc;
+	struct sr_dev_inst *sdi = cb_data;
 
 	(void)fd;
+	(void)revents;
 
 	if (!(sdi = cb_data))
 		return TRUE;
@@ -33,8 +270,55 @@ SR_PRIV int hp_3457a_receive_data(int fd, int revents, void *cb_data)
 	if (!(devc = sdi->priv))
 		return TRUE;
 
-	if (revents == G_IO_IN) {
+	scpi = sdi->conn;
-		/* TODO */
+
+	switch (devc->acq_state) {
+	case ACQ_TRIGGERED_MEASUREMENT:
+		ret = sr_scpi_get_double(scpi, NULL, &devc->base_measurement);
+		if (ret != SR_OK) {
+			retrigger_measurement(scpi, devc);
+			return TRUE;
+		}
+
+		if (is_highres_enabled(devc))
+			request_hires(scpi, devc);
+		else
+			request_range(scpi, devc);
+
+		break;
+	case ACQ_REQUESTED_HIRES:
+		ret = sr_scpi_get_double(scpi, NULL, &devc->hires_register);
+		if (ret != SR_OK) {
+			retrigger_measurement(scpi, devc);
+			return TRUE;
+		}
+		request_range(scpi, devc);
+		break;
+	case ACQ_REQUESTED_RANGE:
+		ret = sr_scpi_get_double(scpi, NULL, &devc->measurement_range);
+		if (ret != SR_OK) {
+			retrigger_measurement(scpi, devc);
+			return TRUE;
+		}
+		devc->acq_state = ACQ_GOT_MEASUREMENT;
+		break;
+	default:
+		return FALSE;
+	}
+
+	if (devc->acq_state == ACQ_GOT_MEASUREMENT)
+		acq_send_measurement(sdi);
+
+	if (devc->limit_samples && (devc->num_samples >= devc->limit_samples)) {
+		sdi->driver->dev_acquisition_stop(sdi, cb_data);
+		return FALSE;
+	}
+
+	/* Got more to go. */
+	if (devc->acq_state == ACQ_GOT_MEASUREMENT) {
+		/* Retrigger */
+		devc->num_samples++;
+		retrigger_measurement(scpi, devc);
 	}
 
 	return TRUE;

src/hardware/hp-3457a/protocol.h

@@ -21,24 +21,56 @@
 #define LIBSIGROK_HARDWARE_HP_3457A_PROTOCOL_H
 
 #include <stdint.h>
-#include <glib.h>
-#include <libsigrok/libsigrok.h>
 #include "libsigrok-internal.h"
 
 #define LOG_PREFIX "hp-3457a"
 
+/* Information about the rear card option currently installed. */
+enum card_type {
+	CARD_UNKNOWN,
+	REAR_TERMINALS,
+	HP_44491A,
+	HP_44492A,
+};
+
+struct rear_card_info {
+	unsigned int card_id;
+	enum card_type type;
+	const char *name;
+	const char *cg_name;
+};
+
+/* Possible states in an acquisition. */
+enum acquisition_state {
+	ACQ_TRIGGERED_MEASUREMENT,
+	ACQ_REQUESTED_HIRES,
+	ACQ_REQUESTED_RANGE,
+	ACQ_GOT_MEASUREMENT,
+};
+
 /** Private, per-device-instance driver context. */
 struct dev_context {
 	/* Model-specific information */
+	/* Information about rear card option, or NULL if unknown */
+	const struct rear_card_info *rear_card;
 
 	/* Acquisition settings */
+	enum sr_mq measurement_mq;
+	enum sr_unit measurement_unit;
+	uint64_t limit_samples;
+	float nplc;
 
 	/* Operational state */
-
+	enum acquisition_state acq_state;
-	/* Temporary state across callbacks */
+	uint64_t num_samples;
-
+	double base_measurement;
+	double hires_register;
+	double measurement_range;
 };
 
+SR_PRIV const struct rear_card_info *hp_3457a_probe_rear_card(struct sr_scpi_dev_inst *scpi);
 SR_PRIV int hp_3457a_receive_data(int fd, int revents, void *cb_data);
+SR_PRIV int hp_3457a_set_mq(const struct sr_dev_inst *sdi, enum sr_mq mq);
+SR_PRIV int hp_3457a_set_nplc(const struct sr_dev_inst *sdi, float nplc);
 
 #endif