raspberrypi-pico: Fix serial comm parameters

[libsigrok.git] / src / hardware / raspberrypi-pico / api.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2022 Shawn Walker <ac0bi00@gmail.com>
 *
 * 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/>.
 */
//debug print levels are err/warn/info/dbg/spew
#include <config.h>
#include <fcntl.h>
#include <glib.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
#include "protocol.h"

//Baud rate is really a don't care because we run USB CDC, dtr must be 1.
//flow should be zero since we don't
//use xon/xoff
#define SERIALCOMM "115200/8n1/dtr=1/rts=0/flow=0"

static const uint32_t scanopts[] = {
	SR_CONF_CONN,		//Required OS name for the port, i.e. /dev/ttyACM0
	SR_CONF_SERIALCOMM,	//Optional config of the port, i.e. 115200/8n1
};

//PulseView reads a sample rate config list as a min, max and step.
//If step is 1 then it creates a 1,2,5,10 set of selects, as well as the max.
//If step is not 1, then it gives a place to enter any value, which gives the greatest flexibility
static const uint64_t samplerates[] = {
	SR_HZ(10),
	SR_MHZ(120),
	SR_HZ(2),
};

static const uint32_t drvopts[] = {
	SR_CONF_OSCILLOSCOPE,
	SR_CONF_LOGIC_ANALYZER,
};

//SW trigger requires this
static const int32_t trigger_matches[] = {
	SR_TRIGGER_ZERO,
	SR_TRIGGER_ONE,
	SR_TRIGGER_RISING,
	SR_TRIGGER_FALLING,
	SR_TRIGGER_EDGE,
};


static const uint32_t devopts[] = {
//CLI prefers LIMIT_SAMPLES to be a list of high,low
	SR_CONF_LIMIT_SAMPLES | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
	SR_CONF_TRIGGER_MATCH | SR_CONF_LIST,
	SR_CONF_CAPTURE_RATIO | SR_CONF_GET | SR_CONF_SET,
//pulseview needs a list return to allow sample rate setting
	SR_CONF_SAMPLERATE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
};

static struct sr_dev_driver raspberrypi_pico_driver_info;


static GSList *scan(struct sr_dev_driver *di, GSList * options)
{
	struct sr_config *src;
	struct sr_dev_inst *sdi;
	struct sr_serial_dev_inst *serial;
	struct dev_context *devc;
	struct sr_channel *ch;
	GSList *l;
	int num_read;
	unsigned int i;
	const char *conn, *serialcomm;
	char buf[32];
	int len;
	uint8_t num_a, num_d, a_size;
	gchar *channel_name;

	conn = serialcomm = NULL;
	for (l = options; l; l = l->next) {
		src = l->data;
		switch (src->key) {
		case SR_CONF_CONN:
			conn = g_variant_get_string(src->data, NULL);
			break;
		case SR_CONF_SERIALCOMM:
			serialcomm = g_variant_get_string(src->data, NULL);
			break;
		}
	}
	if (!conn)
		return NULL;

	if (!serialcomm)
		serialcomm = SERIALCOMM;

	serial = sr_serial_dev_inst_new(conn, serialcomm);
	sr_info("Opening %s.", conn);
	if (serial_open(serial, SERIAL_RDWR) != SR_OK) {
		sr_err("1st serial open fail");
		return NULL;
	}

	sr_info("Resetting device with *s at %s.", conn);
	send_serial_char(serial, '*');
	g_usleep(10000);
	//drain any inflight data
	do {
		sr_warn("Drain reads");
		len = serial_read_blocking(serial, buf, 32, 100);
		sr_warn("Drain reads done");
		if (len)
			sr_dbg("Dropping in flight serial data");
	} while (len > 0);


	//Send identify 
	num_read = send_serial_w_resp(serial, "i\n", buf, 17);
	if (num_read < 16) {
		sr_err("1st identify failed");
		serial_close(serial);
		g_usleep(100000);
		if (serial_open(serial, SERIAL_RDWR) != SR_OK) {
			sr_err("2st serial open fail");
			return NULL;
		}
		g_usleep(100000);
		sr_err("Send second *");
		send_serial_char(serial, '*');
		g_usleep(100000);
		num_read = send_serial_w_resp(serial, "i\n", buf, 17);
		if (num_read < 10) {
			sr_err("Second attempt failed");
			return NULL;
		}
	}
	//Expected ID response is SRPICO,AxxyDzz,VV 
	//where xx are number of analog channels, y is bytes per analog sample
	//and zz is number of digital channels, and VV is two digit version# which must be 00
	if ((num_read < 16)
	    || (strncmp(buf, "SRPICO,A", 8))
	    || (buf[11] != 'D')
	    || (buf[15] != '0')
	    || (buf[16] != '0')) {
		sr_err("ERROR:Bad response string %s %d", buf, num_read);
		return NULL;
	}
	a_size = buf[10] - '0';
	buf[10] = '\0';		//Null to end the str for atois
	buf[14] = '\0';		//Null to end the str for atois
	num_a = atoi(&buf[8]);
	num_d = atoi(&buf[12]);

	sdi = g_malloc0(sizeof(struct sr_dev_inst));
	sdi->status = SR_ST_INACTIVE;
	sdi->vendor = g_strdup("Raspberry Pi");
	sdi->model = g_strdup("PICO");
	sdi->version = g_strdup("00");
	sdi->conn = serial;
	sdi->driver = &raspberrypi_pico_driver_info;
	sdi->inst_type = SR_INST_SERIAL;
	sdi->serial_num = g_strdup("N/A");
	if (((num_a == 0) && (num_d == 0))
	    || (num_a > MAX_ANALOG_CHANNELS)
	    || (num_d > MAX_DIGITAL_CHANNELS)
	    || (a_size < 1)
	    || (a_size > 4)) {
		sr_err("ERROR: invalid channel config a %d d %d asz %d",
		       num_a, num_d, a_size);
		return NULL;
	}
	devc = g_malloc0(sizeof(struct dev_context));
	devc->a_size = a_size;
	//multiple bytes per analog sample not supported
	if ((num_a > 0) && (devc->a_size != 1)) {
		sr_err("Only Analog Size of 1 supported\n\r");
		return NULL;
	}
	devc->num_a_channels = num_a;
	devc->num_d_channels = num_d;
	devc->a_chan_mask = ((1 << num_a) - 1);
	devc->d_chan_mask = ((1 << num_d) - 1);
//The number of bytes that each digital sample in the buffers sent to the session. 
//All logical channels are packed together, where a slice of N channels takes roundup(N/8) bytes
//This never changes even if channels are disabled because PV expects disabled channels to still 
//be accounted for in the packing
	devc->dig_sample_bytes = ((devc->num_d_channels + 7) / 8);
	//These are the slice sizes of the data on the wire
	//1 7 bit field per byte
	devc->bytes_per_slice = (devc->num_a_channels * devc->a_size);
	if (devc->num_d_channels > 0) {
		// logic sent in groups of 7
		devc->bytes_per_slice += (devc->num_d_channels + 6) / 7;
	}
	sr_dbg("num channels a %d d %d bps %d dsb %d", num_a, num_d,
	       devc->bytes_per_slice, devc->dig_sample_bytes);
//Each analog channel is it's own group
//Digital are just channels
//Grouping of channels is rather arbitrary as parameters like sample rate and number of samples
//apply to all changes.  Analog channels do have a scale and offset, but that is applied
//without involvement of the session.
	devc->analog_groups = g_malloc0(sizeof(struct sr_channel_group *) *
					devc->num_a_channels);
	for (i = 0; i < devc->num_a_channels; i++) {
		channel_name = g_strdup_printf("A%d", i);
		//sdi, index, type, enabled,name
		ch = sr_channel_new(sdi, i, SR_CHANNEL_ANALOG, TRUE,
				    channel_name);
		devc->analog_groups[i] =
		    g_malloc0(sizeof(struct sr_channel_group));
		devc->analog_groups[i]->name = channel_name;
		devc->analog_groups[i]->channels =
		    g_slist_append(NULL, ch);
		sdi->channel_groups =
		    g_slist_append(sdi->channel_groups,
				   devc->analog_groups[i]);
	}

	if (devc->num_d_channels > 0) {
		for (i = 0; i < devc->num_d_channels; i++) {
			//Name digital channels starting at D2 to match pico board pin names
			channel_name = g_strdup_printf("D%d", i + 2);
			sr_channel_new(sdi, i, SR_CHANNEL_LOGIC, TRUE,
				       channel_name);
			g_free(channel_name);
		}

	}
	//In large sample usages we get the call to receive with large transfers.
	//Since the CDC serial implemenation can silenty lose data as it gets close to full, allocate
	//storage for a half buffer which in a worst case scenario has 2x ratio of transmitted bytes
	// to storage bytes. 
	//Note: The intent of making this buffer large is to prevent CDC serial buffer overflows.
	//However, it is likely that if the host is running slow (i.e. it's a raspberry pi model 3) that it becomes
	//compute bound and doesn't service CDC serial responses in time to not overflow the internal CDC buffers.
	//And thus no serial buffer is large enough.  But, it's only 256K....
	devc->serial_buffer_size = 256000;
	devc->buffer = NULL;
	sr_dbg("Setting serial buffer size: %i.",
	       devc->serial_buffer_size);
	devc->cbuf_wrptr = 0;
	//While slices are sent as a group of one sample across all channels, sigrok wants analog 
	//channel data sent as separate packets.  
	//Logical trace values are packed together.
	//A serial byte in normal mode never represent more than one sample so a 2x multiplier is plenty.
	//In D4 mode a serial byte can represents 100s of samples due to RLE, but process_D4 ensures that
	//it breaks up the rle_memset calls to prevent overflowing the sample buffer.
	//that it doesn't overflow the sample buffers.
	devc->sample_buf_size = devc->serial_buffer_size * 2;
	for (i = 0; i < devc->num_a_channels; i++) {
		devc->a_data_bufs[i] = NULL;
		devc->a_pretrig_bufs[i] = NULL;
	}
	devc->d_data_buf = NULL;
	devc->sample_rate = 5000;
	devc->capture_ratio = 10;
	devc->rxstate = RX_IDLE;
	sdi->priv = devc;
	//Set an initial value as various code relies on an inital value.
	devc->limit_samples = 1000;

	if (raspberrypi_pico_get_dev_cfg(sdi) != SR_OK) {
		return NULL;
	};

	sr_err("sr_err level logging enabled");
	sr_warn("sr_warn level logging enabled");
	sr_info("sr_info level logging enabled");
	sr_dbg("sr_dbg level logging enabled");
	sr_spew("sr_spew level logging enabled");
	serial_close(serial);
	return std_scan_complete(di, g_slist_append(NULL, sdi));

}



//Note that on the initial driver load we pull all values into local storage.
//Thus gets can return local data, but sets have to issue commands to device.
static int config_set(uint32_t key, GVariant * data,
		      const struct sr_dev_inst *sdi,
		      const struct sr_channel_group *cg)
{
	struct dev_context *devc;
	int ret;
	(void) cg;
	if (!sdi)
		return SR_ERR_ARG;
	devc = sdi->priv;
	ret = SR_OK;
	sr_dbg("Got config_set key %d \n", key);
	switch (key) {
	case SR_CONF_SAMPLERATE:
		devc->sample_rate = g_variant_get_uint64(data);
		sr_dbg("config_set sr %llu\n", devc->sample_rate);
		break;
	case SR_CONF_LIMIT_SAMPLES:
		devc->limit_samples = g_variant_get_uint64(data);
		sr_dbg("config_set slimit %lld\n", devc->limit_samples);
		break;
	case SR_CONF_CAPTURE_RATIO:
		devc->capture_ratio = g_variant_get_uint64(data);
		break;

	default:
		sr_err("ERROR:config_set undefine %d\n", key);
		ret = SR_ERR_NA;
	}

	return ret;
}

static int config_get(uint32_t key, GVariant ** data,
		      const struct sr_dev_inst *sdi,
		      const struct sr_channel_group *cg)
{
	struct dev_context *devc;
	sr_dbg("at config_get key %d", key);
	(void) cg;
	if (!sdi)
		return SR_ERR_ARG;

	devc = sdi->priv;
	switch (key) {
	case SR_CONF_SAMPLERATE:
		*data = g_variant_new_uint64(devc->sample_rate);
		sr_spew("sample rate get of %lld", devc->sample_rate);
		break;
	case SR_CONF_CAPTURE_RATIO:
		if (!sdi)
			return SR_ERR;
		devc = sdi->priv;
		*data = g_variant_new_uint64(devc->capture_ratio);
		break;
	case SR_CONF_LIMIT_SAMPLES:
		sr_spew("config_get limit_samples of %llu",
			devc->limit_samples);
		*data = g_variant_new_uint64(devc->limit_samples);
		break;
	default:
		sr_spew("unsupported cfg_get key %d", key);
		return SR_ERR_NA;
	}
	return SR_OK;
}

static int config_list(uint32_t key, GVariant ** data,
		       const struct sr_dev_inst *sdi,
		       const struct sr_channel_group *cg)
{
	(void) cg;
	//scan or device options are the only ones that can be called without a defined instance
	if ((key == SR_CONF_SCAN_OPTIONS)
	    || (key == SR_CONF_DEVICE_OPTIONS)) {
		return STD_CONFIG_LIST(key, data, sdi, cg, scanopts,
				       drvopts, devopts);
	}
	if (!sdi) {
		sr_err
		    ("ERROR:\n\r\n\r\n\r Call to config list with null sdi\n\r\n\r");
		return SR_ERR_ARG;
	}
	sr_dbg("start config_list with key %X\n", key);
	switch (key) {
//Pulseview in  pulseview/pv/toolbars/mainbar.cpp requires list support for frequencies as a triple
//of min,max,step.  If step is 1, then it proves a 1,2,5,10 select, but if not 1 it allows a spin box
	case SR_CONF_SAMPLERATE:
		sr_dbg("Return sample rate list");
		*data =
		    std_gvar_samplerates_steps(ARRAY_AND_SIZE
					       (samplerates));
		break;
//This must be set to get SW trigger support
	case SR_CONF_TRIGGER_MATCH:
		*data =
		    std_gvar_array_i32(ARRAY_AND_SIZE(trigger_matches));
		break;
	case SR_CONF_LIMIT_SAMPLES:
		//Really this limit is up to the memory capacity of the host,
		//and users that pick huge values deserve what they get.
		//But setting this limit to prevent really crazy things.
		*data = std_gvar_tuple_u64(1LL, 1000000000LL);
		sr_dbg("sr_config_list limit samples ");
		break;
	default:
		sr_dbg("reached default statement of config_list");

		return SR_ERR_NA;
	}

	return SR_OK;
}

static int dev_acquisition_start(const struct sr_dev_inst *sdi)
{
	struct sr_serial_dev_inst *serial;
	struct dev_context *devc;
	struct sr_channel *ch;
	struct sr_trigger *trigger;
	char tmpstr[20];
	GSList *l;
	int a_enabled = 0, d_enabled = 0, len;
	serial = sdi->conn;
	int i;
	devc = sdi->priv;
	sr_dbg("Enter acq start");
	sr_dbg("dsbstart %d", devc->dig_sample_bytes);
	devc->buffer = g_malloc(devc->serial_buffer_size);
	if (!(devc->buffer)) {
		sr_err("ERROR:serial buffer malloc fail");
		return SR_ERR_MALLOC;
	}
	//Get device in idle state
	if (serial_drain(serial) != SR_OK) {
		sr_err("Initial Drain Failed\n\r");
		return SR_ERR;
	}
	send_serial_char(serial, '*');
	if (serial_drain(serial) != SR_OK) {
		sr_err("Second Drain Failed\n\r");
		return SR_ERR;
	}

	for (l = sdi->channels; l; l = l->next) {
		ch = l->data;
		sr_dbg("c %d enabled %d name %s\n", ch->index, ch->enabled,
		       ch->name);

		if (ch->name[0] == 'A') {
			devc->a_chan_mask &= ~(1 << ch->index);
			if (ch->enabled) {
				devc->a_chan_mask |=
				    (ch->enabled << ch->index);
				a_enabled++;
			}
//           sr_dbg("A%d en %d mask 0x%X",ch->index,ch->enabled,devc->a_chan_mask);

		}
		if (ch->name[0] == 'D') {
			devc->d_chan_mask &= ~(1 << ch->index);
			if (ch->enabled) {
				devc->d_chan_mask |=
				    (ch->enabled << ch->index);
				d_enabled++;
				//            sr_dbg("D%d en %d mask 0x%X",ch->index,ch->enabled,devc->d_chan_mask);
			}
		}
		sr_info("Channel enable masks D 0x%X A 0x%X",
			devc->d_chan_mask, devc->a_chan_mask);
		sprintf(tmpstr, "%c%d%d\n", ch->name[0], ch->enabled,
			ch->index);
		if (send_serial_w_ack(serial, tmpstr) != SR_OK) {
			sr_err("ERROR:Channel enable fail");
			return SR_ERR;
		} else {

		}
	}			//for all channels
	//ensure data channels are continuous
	int invalid = 0;
	for (i = 0; i < 32; i++) {
		if ((devc->d_chan_mask >> i) & 1) {
			if (invalid) {
				sr_err
				    ("Digital channel mask 0x%X not continous\n\r",
				     devc->d_chan_mask);
				return SR_ERR;
			}
		} else {
			invalid = 1;
		}
	}
	//recalculate bytes_per_slice.  
	devc->bytes_per_slice = (a_enabled * devc->a_size);

	for (i = 0; i < devc->num_d_channels; i += 7) {
		if (((devc->d_chan_mask) >> i) & (0x7F)) {
			(devc->bytes_per_slice)++;
		}
	}
	if ((a_enabled == 0) && (d_enabled == 0)) {
		sr_err("ERROR:No channels enabled");
		return SR_ERR;
	}
	sr_dbg("bps %d\n", devc->bytes_per_slice);

	//Apply sample rate limits
	//Save off the lower rate values which are hacked way of getting configs to the device
	uint8_t cfg_bits;
	cfg_bits = (devc->sample_rate % 10 & 0x6);	//Only bits 2&1 are used as cfg_bits
	devc->sample_rate -= cfg_bits;
	sr_warn("Capture device cfg_bits of 0x%X from sample rate %lld",
		cfg_bits, devc->sample_rate);
	if ((a_enabled == 3) && (devc->sample_rate > 166660)) {
		sr_err
		    ("ERROR:3 channel ADC sample rate dropped to 166.660khz");
		devc->sample_rate = 166660;
	}
	if ((a_enabled == 2) && (devc->sample_rate > 250000)) {
		sr_err
		    ("ERROR:2 channel ADC sample rate dropped to 250khz");
		devc->sample_rate = 250000;
	}
	if ((a_enabled == 1) && (devc->sample_rate > 500000)) {
		sr_err
		    ("ERROR:1 channel ADC sample rate dropped to 500khz");
		devc->sample_rate = 500000;
	}
	//Depending on channel configs, rates below 5ksps are possible
	//but such a low rate can easily stream and this eliminates a lot
	//of special cases.
	if (devc->sample_rate < 5000) {
		sr_err("Sample rate override to min of 5ksps");
		devc->sample_rate = 5000;
	}
	if (devc->sample_rate > 120000000) {
		sr_err("Sample rate override to max of 120Msps");
		devc->sample_rate = 12000000;
	}
	//It may take a very large number of samples to notice, but if digital and analog are enabled
	//and either PIO or ADC are fractional the samples will skew over time.
	//24Mhz is the max common divisor to the 120Mhz and 48Mhz ADC clock
	//so force an integer divisor to it.
	if ((a_enabled > 0) && (d_enabled > 0)) {
		if (24000000ULL % (devc->sample_rate)) {
			uint32_t commondivint =
			    24000000ULL / (devc->sample_rate);
			//Always increment the divisor so that we go down in frequency to avoid max sample rate issues
			commondivint++;
			devc->sample_rate = 24000000ULL / commondivint;
			//While the common divisor is an integer, that does not mean the resulting sample rate is, and
			//we want to keep the sample_rate divisible by 10 to support the cfg_bits
			while ((devc->sample_rate % 10)
			       && (commondivint < 4800)) {
				commondivint++;
				devc->sample_rate =
				    24000000ULL / commondivint;
				//sr_err(" sample rate of %llu div %u\n\r",devc->sample_rate,commondivint); 
			}
			//Make sure the divisor increement didn't make use go too low.
			if (devc->sample_rate < 5000) {
				devc->sample_rate = 50000;
			}
			sr_err
			    ("WARN: Forcing common integer divisor sample rate of %llu div %u\n\r",
			     devc->sample_rate, commondivint);
		}

	}
	//If we are only digital only or only analog print a warning that the 
	//fractional divisors aren't a true PLL fractional feedback loop and thus
	//could have sample to sample variation.
	if (a_enabled > 0) {
		if (48000000ULL % (devc->sample_rate * a_enabled)) {
			sr_warn
			    ("WARN: Non integer ADC divisor of 48Mhz clock for sample rate %llu may cause sample to sample variability.",
			     devc->sample_rate);
		}
	}
	if (d_enabled > 0) {
		if (120000000ULL % (devc->sample_rate)) {
			sr_warn
			    ("WARN: Non integer PIO divisor of 120Mhz for sample rate %llu may cause sample to sample variability.",
			     devc->sample_rate);
		}
	}

	//modulo 10 to add cfg_bits back in
	//All code above should create overrides that are multiples of 10, but add a check just in case.
	if (devc->sample_rate % 10) {
		sr_err("Output sample rate %llu not mod 10",
		       devc->sample_rate);
		devc->sample_rate = (devc->sample_rate / 10) * 10;
	}

	devc->sample_rate += cfg_bits;
	if (cfg_bits) {
		sr_warn
		    ("Embedding cfg_bits of 0x%X in sample_rate %lld\n\r",
		     cfg_bits, devc->sample_rate);
	}
	sprintf(&tmpstr[0], "R%llu\n", devc->sample_rate);
	if (send_serial_w_ack(serial, tmpstr) != SR_OK) {
		sr_err("Sample rate to device failed");
		return SR_ERR;
	}
	sprintf(tmpstr, "L%lld\n", devc->limit_samples);
	if (send_serial_w_ack(serial, tmpstr) != SR_OK) {
		sr_err("Sample limit to device failed");
		return SR_ERR;
	}


	devc->sent_samples = 0;
	devc->byte_cnt = 0;
	devc->bytes_avail = 0;
	devc->wrptr = 0;
	devc->cbuf_wrptr = 0;
	len =
	    serial_read_blocking(serial, devc->buffer,
				 devc->serial_buffer_size,
				 serial_timeout(serial, 4));
	if (len > 0) {
		sr_info("Pre-ARM drain had %d characters:", len);
		devc->buffer[len] = 0;
		sr_info("%s", devc->buffer);
	}

	for (i = 0; i < devc->num_a_channels; i++) {
		devc->a_data_bufs[i] =
		    g_malloc(devc->sample_buf_size * sizeof(float));
		if (!(devc->a_data_bufs[i])) {
			sr_err("ERROR:analog buffer malloc fail");
			return SR_ERR_MALLOC;
		}
	}
	if (devc->num_d_channels > 0) {
		devc->d_data_buf =
		    g_malloc(devc->sample_buf_size *
			     devc->dig_sample_bytes);
		if (!(devc->d_data_buf)) {
			sr_err("ERROR:logic buffer malloc fail");
			return SR_ERR_MALLOC;
		}
	}

	if ((trigger = sr_session_trigger_get(sdi->session))) {
		devc->pretrig_entries =
		    (devc->capture_ratio * devc->limit_samples) / 100;
		devc->stl =
		    soft_trigger_logic_new(sdi, trigger,
					   devc->pretrig_entries);
		if (!devc->stl)
			return SR_ERR_MALLOC;
		devc->trigger_fired = FALSE;
		if (devc->pretrig_entries > 0) {
			sr_dbg("Allocating pretrig buffers size %d",
			       devc->pretrig_entries);
			for (i = 0; i < devc->num_a_channels; i++) {
				if ((devc->a_chan_mask >> i) & 1) {
					devc->a_pretrig_bufs[i] =
					    g_malloc0(sizeof(float) *
						      devc->
						      pretrig_entries);
					if (!devc->a_pretrig_bufs[i]) {
						sr_err
						    ("ERROR:Analog pretrigger buffer malloc failure, disabling");
						devc->trigger_fired = TRUE;
					}
				}	//if chan_mask
			}	//for num_a_channels
		}		//if pre_trigger
		sr_info("Entering sw triggered mode");
		//post the receive before starting the device to ensure we are ready to receive data ASAP
		serial_source_add(sdi->session, serial, G_IO_IN, 200,
				  raspberrypi_pico_receive, (void *) sdi);
		sprintf(tmpstr, "C\n");
		if (send_serial_str(serial, tmpstr) != SR_OK)
			return SR_ERR;

	} else {
		devc->trigger_fired = TRUE;
		devc->pretrig_entries = 0;
		sr_info("Entering fixed sample mode");
		serial_source_add(sdi->session, serial, G_IO_IN, 200,
				  raspberrypi_pico_receive, (void *) sdi);
		sprintf(tmpstr, "F\n");
		if (send_serial_str(serial, tmpstr) != SR_OK)
			return SR_ERR;
	}
	std_session_send_df_header(sdi);

	sr_dbg("dsbstartend %d", devc->dig_sample_bytes);

	if (devc->trigger_fired)
		std_session_send_df_trigger(sdi);
	//Keep this at the end as we don't want to be RX_ACTIVE unless everything is ok
	devc->rxstate = RX_ACTIVE;

	return SR_OK;
}

//This function is called either by the protocol code if we reached all of the samples 
//or an error condition, and also by the user clicking stop in pulseview.
//It must always be called for any acquistion that was started to free memory.
static int dev_acquisition_stop(struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	struct sr_serial_dev_inst *serial;
	sr_dbg("****at dev_acquisition_stop");
	int len;
	devc = sdi->priv;
	serial = sdi->conn;

	std_session_send_df_end(sdi);
	//If we reached this while still active it is likely because the stop button was pushed 
	//in pulseview.
	//That is generally some kind of error condition, so we don't try to check the bytenct
	if (devc->rxstate == RX_ACTIVE) {
		sr_err("Reached dev_acquisition_stop in RX_ACTIVE");
	}
	if (devc->rxstate != RX_IDLE) {
		sr_err("Sending plus to stop device stream\n\r");
		send_serial_char(serial, '+');
	}
	//In case we get calls to receive force it to exit
	devc->rxstate = RX_IDLE;
	//drain data from device so that it doesn't confuse subsequent commands
	do {
		len =
		    serial_read_blocking(serial, devc->buffer,
					 devc->serial_buffer_size, 100);
		if (len)
			sr_err("Dropping %d device bytes\n\r", len);
	} while (len > 0);



	if (devc->buffer) {
		g_free(devc->buffer);
		devc->buffer = NULL;
	}

	for (int i = 0; i < devc->num_a_channels; i++) {
		if (devc->a_data_bufs[i]) {
			g_free(devc->a_data_bufs[i]);
			devc->a_data_bufs[i] = NULL;
		}
	}

	if (devc->d_data_buf) {
		g_free(devc->d_data_buf);
		devc->d_data_buf = NULL;
	}
	for (int i = 0; i < devc->num_a_channels; i++) {
		if (devc->a_pretrig_bufs[i])
			g_free(devc->a_pretrig_bufs[i]);
		devc->a_pretrig_bufs[i] = NULL;
	}

	serial = sdi->conn;
	serial_source_remove(sdi->session, serial);

	return SR_OK;
}

static struct sr_dev_driver raspberrypi_pico_driver_info = {
	.name = "raspberrypi-pico",
	.longname = "RaspberryPI PICO",
	.api_version = 1,
	.init = std_init,
	.cleanup = std_cleanup,
	.scan = scan,
	.dev_list = std_dev_list,
	.dev_clear = std_dev_clear,
	.config_get = config_get,
	.config_set = config_set,
	.config_list = config_list,
	.dev_open = std_serial_dev_open,
	.dev_close = std_serial_dev_close,
	.dev_acquisition_start = dev_acquisition_start,
	.dev_acquisition_stop = dev_acquisition_stop,
	.context = NULL,
};

SR_REGISTER_DEV_DRIVER(raspberrypi_pico_driver_info);