demo: Get/Set amplitude while data acquisition is running.

src/hardware/demo/api.c

@@ -33,9 +33,6 @@
 #define DEFAULT_LOGIC_PATTERN			PATTERN_SIGROK
 
 #define DEFAULT_NUM_ANALOG_CHANNELS		4
-#define DEFAULT_ANALOG_ENCODING_DIGITS	4
-#define DEFAULT_ANALOG_SPEC_DIGITS		4
-#define DEFAULT_ANALOG_AMPLITUDE		10
 
 /* Note: No spaces allowed because of sigrok-cli. */
 static const char *logic_pattern_str[] = {
@@ -165,6 +162,13 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 	/* Analog channels, channel groups and pattern generators. */
 	devc->ch_ag = g_hash_table_new(g_direct_hash, g_direct_equal);
 	if (num_analog_channels > 0) {
+		/*
+		 * Have the waveform for analog patterns pre-generated. It's
+		 * supposed to be periodic, so the generator just needs to
+		 * access the prepared sample data (DDS style).
+		 */
+		demo_generate_analog_pattern(devc);
+
 		pattern = 0;
 		/* An "Analog" channel group with all analog channels in it. */
 		acg = g_malloc0(sizeof(struct sr_channel_group));
@@ -190,6 +194,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 			ag->mq_flags = SR_MQFLAG_DC;
 			ag->unit = SR_UNIT_VOLT;
 			ag->amplitude = DEFAULT_ANALOG_AMPLITUDE;
+			ag->offset = DEFAULT_ANALOG_OFFSET;
 			sr_analog_init(&ag->packet, &ag->encoding, &ag->meaning, &ag->spec, 2);
 			ag->packet.meaning->channels = cg->channels;
 			ag->packet.meaning->mq = ag->mq;
@@ -197,7 +202,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 			ag->packet.meaning->unit = ag->unit;
 			ag->packet.encoding->digits = DEFAULT_ANALOG_ENCODING_DIGITS;
 			ag->packet.spec->spec_digits = DEFAULT_ANALOG_SPEC_DIGITS;
-			ag->packet.data = ag->pattern_data;
+			ag->packet.data = devc->analog_patterns[pattern];
 			ag->pattern = pattern;
 			ag->avg_val = 0.0f;
 			ag->num_avgs = 0;
@@ -472,8 +477,6 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
 	struct sr_channel *ch;
 	int bitpos;
 	uint8_t mask;
-	GHashTableIter iter;
-	void *value;
 	struct sr_trigger *trigger;
 
 	devc = sdi->priv;
@@ -539,15 +542,6 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
 		devc->first_partial_logic_index,
 		devc->first_partial_logic_mask);
 
-	/*
-	 * Have the waveform for analog patterns pre-generated. It's
-	 * supposed to be periodic, so the generator just needs to
-	 * access the prepared sample data (DDS style).
-	 */
-	g_hash_table_iter_init(&iter, devc->ch_ag);
-	while (g_hash_table_iter_next(&iter, NULL, &value))
-		demo_generate_analog_pattern(value, devc->cur_samplerate);
-
 	sr_session_source_add(sdi->session, -1, 0, 100,
 			demo_prepare_data, (struct sr_dev_inst *)sdi);
 

src/hardware/demo/protocol.c

@@ -173,77 +173,75 @@ static const uint8_t pattern_squid[128][128 / 8] = {
 	{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, },
 };
 
-SR_PRIV void demo_generate_analog_pattern(struct analog_gen *ag, uint64_t sample_rate)
+SR_PRIV void demo_generate_analog_pattern(struct dev_context *devc)
 {
 	double t, frequency;
-	float value;
+	float amplitude, offset;
+	struct analog_pattern *pattern;
 	unsigned int num_samples, i;
+	float value;
 	int last_end;
 
-	sr_dbg("Generating %s pattern.", analog_pattern_str[ag->pattern]);
-
 	num_samples = ANALOG_BUFSIZE / sizeof(float);
+	frequency = (double) devc->cur_samplerate / ANALOG_SAMPLES_PER_PERIOD;
+	amplitude = DEFAULT_ANALOG_AMPLITUDE;
+	offset = DEFAULT_ANALOG_OFFSET;
 
-	switch (ag->pattern) {
+	/* FIXME we actually need only one period. A ringbuffer would be
-	case PATTERN_SQUARE:
+	 * useful here. */
-		value = ag->amplitude;
+	/* Make sure the number of samples we put out is an integer
-		last_end = 0;
+	 * multiple of our period size */
-		for (i = 0; i < num_samples; i++) {
-			if (i % 5 == 0)
-				value = -value;
-			if (i % 10 == 0)
-				last_end = i;
-			ag->pattern_data[i] = value;
-		}
-		ag->num_samples = last_end;
-		break;
-	case PATTERN_SINE:
-		frequency = (double) sample_rate / ANALOG_SAMPLES_PER_PERIOD;
 
-		/* Make sure the number of samples we put out is an integer
+	/* PATTERN_SQUARE */
-		 * multiple of our period size */
+	sr_dbg("Generating %s pattern.", analog_pattern_str[PATTERN_SQUARE]);
-		/* FIXME we actually need only one period. A ringbuffer would be
+	pattern = g_malloc(sizeof(struct analog_pattern));
-		 * useful here. */
+	value = amplitude;
-		while (num_samples % ANALOG_SAMPLES_PER_PERIOD != 0)
+	last_end = 0;
-			num_samples--;
+	for (i = 0; i < num_samples; i++) {
-
+		if (i % 5 == 0)
-		for (i = 0; i < num_samples; i++) {
+			value = -value;
-			t = (double) i / (double) sample_rate;
+		if (i % 10 == 0)
-			ag->pattern_data[i] = ag->amplitude *
+			last_end = i;
-						sin(2 * G_PI * frequency * t);
+		pattern->data[i] = value + offset;
-		}
-
-		ag->num_samples = num_samples;
-		break;
-	case PATTERN_TRIANGLE:
-		frequency = (double) sample_rate / ANALOG_SAMPLES_PER_PERIOD;
-
-		while (num_samples % ANALOG_SAMPLES_PER_PERIOD != 0)
-			num_samples--;
-
-		for (i = 0; i < num_samples; i++) {
-			t = (double) i / (double) sample_rate;
-			ag->pattern_data[i] = (2 * ag->amplitude / G_PI) *
-						asin(sin(2 * G_PI * frequency * t));
-		}
-
-		ag->num_samples = num_samples;
-		break;
-	case PATTERN_SAWTOOTH:
-		frequency = (double) sample_rate / ANALOG_SAMPLES_PER_PERIOD;
-
-		while (num_samples % ANALOG_SAMPLES_PER_PERIOD != 0)
-			num_samples--;
-
-		for (i = 0; i < num_samples; i++) {
-			t = (double) i / (double) sample_rate;
-			ag->pattern_data[i] = 2 * ag->amplitude *
-						((t * frequency) - floor(0.5f + t * frequency));
-		}
-
-		ag->num_samples = num_samples;
-		break;
 	}
+	pattern->num_samples = last_end;
+	devc->analog_patterns[PATTERN_SQUARE] = pattern;
+
+	/*  Readjusting num_samples for all other patterns */
+	while (num_samples % ANALOG_SAMPLES_PER_PERIOD != 0)
+		num_samples--;
+
+	/* PATTERN_SINE: */
+	sr_dbg("Generating %s pattern.", analog_pattern_str[PATTERN_SINE]);
+	pattern = g_malloc(sizeof(struct analog_pattern));
+	for (i = 0; i < num_samples; i++) {
+		t = (double) i / (double) devc->cur_samplerate;
+		pattern->data[i] = sin(2 * G_PI * frequency * t) * amplitude + offset;
+	}
+	pattern->num_samples = last_end;
+	devc->analog_patterns[PATTERN_SINE] = pattern;
+
+	/* PATTERN_TRIANGLE: */
+	sr_dbg("Generating %s pattern.", analog_pattern_str[PATTERN_TRIANGLE]);
+	pattern = g_malloc(sizeof(struct analog_pattern));
+	for (i = 0; i < num_samples; i++) {
+		t = (double) i / (double) devc->cur_samplerate;
+		pattern->data[i] = (2 / G_PI) * asin(sin(2 * G_PI * frequency * t)) *
+			amplitude + offset;
+	}
+	pattern->num_samples = last_end;
+	devc->analog_patterns[PATTERN_TRIANGLE] = pattern;
+
+	/* PATTERN_SAWTOOTH: */
+	sr_dbg("Generating %s pattern.", analog_pattern_str[PATTERN_SAWTOOTH]);
+	pattern = g_malloc(sizeof(struct analog_pattern));
+	for (i = 0; i < num_samples; i++) {
+		t = (double) i / (double) devc->cur_samplerate;
+		pattern->data[i] = 2 * ((t * frequency) - floor(0.5f + t * frequency)) *
+			amplitude + offset;
+	}
+	pattern->num_samples = last_end;
+	devc->analog_patterns[PATTERN_SAWTOOTH] = pattern;
 }
 
 static uint64_t encode_number_to_gray(uint64_t nr)
@@ -390,9 +388,12 @@ static void send_analog_packet(struct analog_gen *ag,
 {
 	struct sr_datafeed_packet packet;
 	struct dev_context *devc;
+	struct analog_pattern *pattern;
 	uint64_t sending_now, to_avg;
 	int ag_pattern_pos;
 	unsigned int i;
+	float amplitude, offset, value;
+	float *data;
 
 	if (!ag->ch || !ag->ch->enabled)
 		return;
@@ -401,6 +402,8 @@ static void send_analog_packet(struct analog_gen *ag,
 	packet.type = SR_DF_ANALOG;
 	packet.payload = &ag->packet;
 
+	pattern = devc->analog_patterns[ag->pattern];
+
 	ag->packet.meaning->channels = g_slist_append(NULL, ag->ch);
 	ag->packet.meaning->mq = ag->mq;
 	ag->packet.meaning->mqflags = ag->mq_flags;
@@ -476,22 +479,36 @@ static void send_analog_packet(struct analog_gen *ag,
 		ag->packet.meaning->unit = SR_UNIT_UNITLESS;
 
 	if (!devc->avg) {
-		ag_pattern_pos = analog_pos % ag->num_samples;
+		ag_pattern_pos = analog_pos % pattern->num_samples;
-		sending_now = MIN(analog_todo, ag->num_samples - ag_pattern_pos);
+		sending_now = MIN(analog_todo, pattern->num_samples - ag_pattern_pos);
-		ag->packet.data = ag->pattern_data + ag_pattern_pos;
+		if (ag->amplitude != DEFAULT_ANALOG_AMPLITUDE ||
+			ag->offset != DEFAULT_ANALOG_OFFSET) {
+
+			/* Amplitude or offset changed, modify each sample */
+			amplitude = ag->amplitude / DEFAULT_ANALOG_AMPLITUDE;
+			offset = ag->offset - DEFAULT_ANALOG_OFFSET;
+			data = ag->packet.data;
+			for (i = 0; i < sending_now; i++) {
+				data[i] = pattern->data[ag_pattern_pos + i] * amplitude + offset;
+			}
+		} else {
+			/* Amplitude and offset not changed, use the fast way */
+			ag->packet.data = pattern->data + ag_pattern_pos;
+		}
 		ag->packet.num_samples = sending_now;
 		sr_session_send(sdi, &packet);
 
 		/* Whichever channel group gets there first. */
 		*analog_sent = MAX(*analog_sent, sending_now);
 	} else {
-		ag_pattern_pos = analog_pos % ag->num_samples;
+		ag_pattern_pos = analog_pos % pattern->num_samples;
-		to_avg = MIN(analog_todo, ag->num_samples - ag_pattern_pos);
+		to_avg = MIN(analog_todo, pattern->num_samples - ag_pattern_pos);
+		amplitude = ag->amplitude / DEFAULT_ANALOG_AMPLITUDE;
+		offset = ag->offset - DEFAULT_ANALOG_OFFSET;
 
 		for (i = 0; i < to_avg; i++) {
-			ag->avg_val = (ag->avg_val +
+			value = *(pattern->data + ag_pattern_pos + i) * amplitude + offset;
-					*(ag->pattern_data +
+			ag->avg_val = (ag->avg_val + value) / 2;
-					  ag_pattern_pos + i)) / 2;
 			ag->num_avgs++;
 			/* Time to send averaged data? */
 			if ((devc->avg_samples > 0) && (ag->num_avgs >= devc->avg_samples))
@@ -499,7 +516,8 @@ static void send_analog_packet(struct analog_gen *ag,
 		}
 
 		if (devc->avg_samples == 0) {
-			/* We're averaging all the samples, so wait with
+			/*
+			 * We're averaging all the samples, so wait with
 			 * sending until the very end.
 			 */
 			*analog_sent = ag->num_avgs;

src/hardware/demo/protocol.h

@@ -38,6 +38,11 @@
 #define SAMPLES_PER_FRAME		1000UL
 #define DEFAULT_LIMIT_FRAMES		0
 
+#define DEFAULT_ANALOG_ENCODING_DIGITS	4
+#define DEFAULT_ANALOG_SPEC_DIGITS		4
+#define DEFAULT_ANALOG_AMPLITUDE		10
+#define DEFAULT_ANALOG_OFFSET			0.
+
 /* Logic patterns we can generate. */
 enum logic_pattern_type {
 	/**
@@ -92,6 +97,18 @@ enum analog_pattern_type {
 	PATTERN_SAWTOOTH,
 };
 
+static const char *analog_pattern_str[] = {
+	"square",
+	"sine",
+	"triangle",
+	"sawtooth",
+};
+
+struct analog_pattern {
+	float data[ANALOG_BUFSIZE];
+	unsigned int num_samples;
+};
+
 struct dev_context {
 	uint64_t cur_samplerate;
 	uint64_t limit_samples;
@@ -110,6 +127,7 @@ struct dev_context {
 	enum logic_pattern_type logic_pattern;
 	uint8_t logic_data[LOGIC_BUFSIZE];
 	/* Analog */
+	struct analog_pattern *analog_patterns[ARRAY_SIZE(analog_pattern_str)];
 	int32_t num_analog_channels;
 	GHashTable *ch_ag;
 	gboolean avg; /* True if averaging is enabled */
@@ -124,13 +142,6 @@ struct dev_context {
 	struct soft_trigger_logic *stl;
 };
 
-static const char *analog_pattern_str[] = {
-	"square",
-	"sine",
-	"triangle",
-	"sawtooth",
-};
-
 struct analog_gen {
 	struct sr_channel *ch;
 	enum sr_mq mq;
@@ -138,8 +149,7 @@ struct analog_gen {
 	enum sr_unit unit;
 	enum analog_pattern_type pattern;
 	float amplitude;
-	float pattern_data[ANALOG_BUFSIZE];
+	float offset;
-	unsigned int num_samples;
 	struct sr_datafeed_analog packet;
 	struct sr_analog_encoding encoding;
 	struct sr_analog_meaning meaning;
@@ -148,7 +158,7 @@ struct analog_gen {
 	unsigned int num_avgs; /* Number of samples averaged */
 };
 
-SR_PRIV void demo_generate_analog_pattern(struct analog_gen *ag, uint64_t sample_rate);
+SR_PRIV void demo_generate_analog_pattern(struct dev_context *devc);
 SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data);
 
 #endif