src/hardware/lecroy-xstream/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2017 Sven Schnelle <svens@stackframe.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <math.h>
  22 #include <stdlib.h>
  23 #include "scpi.h"
  24 #include "protocol.h"
  25
  26 struct lecroy_wavedesc_2_x {
  27         uint16_t comm_type;
  28         uint16_t comm_order; /* 1 - little endian */
  29         uint32_t wave_descriptor_length;
  30         uint32_t user_text_len;
  31         uint32_t res_desc1;
  32         uint32_t trigtime_array_length;
  33         uint32_t ris_time1_array_length;
  34         uint32_t res_array1;
  35         uint32_t wave_array1_length;
  36         uint32_t wave_array2_length;
  37         uint32_t wave_array3_length;
  38         uint32_t wave_array4_length;
  39         char instrument_name[16];
  40         uint32_t instrument_number;
  41         char trace_label[16];
  42         uint32_t reserved;
  43         uint32_t wave_array_count;
  44         uint32_t points_per_screen;
  45         uint32_t first_valid_point;
  46         uint32_t last_valid_point;
  47         uint32_t first_point;
  48         uint32_t sparsing_factor;
  49         uint32_t segment_index;
  50         uint32_t subarray_count;
  51         uint32_t sweeps_per_acq;
  52         uint16_t points_per_pair;
  53         uint16_t pair_offset;
  54         float vertical_gain;
  55         float vertical_offset;
  56         float max_value;
  57         float min_value;
  58         uint16_t nominal_bits;
  59         uint16_t nom_subarray_count;
  60         float horiz_interval;
  61         double horiz_offset;
  62         double pixel_offset;
  63         char vertunit[48];
  64         char horunit[48];
  65         uint32_t reserved1;
  66         double trigger_time;
  67 } __attribute__((packed));
  68
  69 struct lecroy_wavedesc {
  70         char descriptor_name[16];
  71         char template_name[16];
  72         union {
  73                 struct lecroy_wavedesc_2_x version_2_x;
  74         };
  75 } __attribute__((packed));
  76
  77 static const char *coupling_options[] = {
  78         "A1M", ///< AC with 1 MOhm termination
  79         "D50", ///< DC with 50 Ohm termination
  80         "D1M", ///< DC with 1 MOhm termination
  81         "GND",
  82         "OVL",
  83 };
  84
  85 static const char *scope_trigger_slopes[] = {
  86         "POS", "NEG",
  87 };
  88
  89 static const char *trigger_sources[] = {
  90         "C1", "C2", "C3", "C4", "LINE", "EXT",
  91 };
  92
  93 static const uint64_t timebases[][2] = {
  94         /* picoseconds */
  95         { 20, UINT64_C(1000000000000) },
  96         { 50, UINT64_C(1000000000000) },
  97         { 100, UINT64_C(1000000000000) },
  98         { 200, UINT64_C(1000000000000) },
  99         { 500, UINT64_C(1000000000000) },
 100         /* nanoseconds */
 101         { 1, 1000000000 },
 102         { 2, 1000000000 },
 103         { 5, 1000000000 },
 104         { 10, 1000000000 },
 105         { 20, 1000000000 },
 106         { 50, 1000000000 },
 107         { 100, 1000000000 },
 108         { 200, 1000000000 },
 109         { 500, 1000000000 },
 110         /* microseconds */
 111         { 1, 1000000 },
 112         { 2, 1000000 },
 113         { 5, 1000000 },
 114         { 10, 1000000 },
 115         { 20, 1000000 },
 116         { 50, 1000000 },
 117         { 100, 1000000 },
 118         { 200, 1000000 },
 119         { 500, 1000000 },
 120         /* milliseconds */
 121         { 1, 1000 },
 122         { 2, 1000 },
 123         { 5, 1000 },
 124         { 10, 1000 },
 125         { 20, 1000 },
 126         { 50, 1000 },
 127         { 100, 1000 },
 128         { 200, 1000 },
 129         { 500, 1000 },
 130         /* seconds */
 131         { 1, 1 },
 132         { 2, 1 },
 133         { 5, 1 },
 134         { 10, 1 },
 135         { 20, 1 },
 136         { 50, 1 },
 137         { 100, 1 },
 138         { 200, 1 },
 139         { 500, 1 },
 140         { 1000, 1 },
 141 };
 142
 143 static const uint64_t vdivs[][2] = {
 144         /* millivolts */
 145         { 1, 1000 },
 146         { 2, 1000 },
 147         { 5, 1000 },
 148         { 10, 1000 },
 149         { 20, 1000 },
 150         { 50, 1000 },
 151         { 100, 1000 },
 152         { 200, 1000 },
 153         { 500, 1000 },
 154         /* volts */
 155         { 1, 1 },
 156         { 2, 1 },
 157         { 5, 1 },
 158         { 10, 1 },
 159         { 20, 1 },
 160         { 50, 1 },
 161 };
 162
 163 static const char *scope_analog_channel_names[] = {
 164         "CH1", "CH2", "CH3", "CH4",
 165 };
 166
 167 static const struct scope_config scope_models[] = {
 168         {
 169                  /* Default config */
 170                 .name = {NULL},
 171
 172                 .analog_channels = 4,
 173                 .analog_names = &scope_analog_channel_names,
 174
 175                 .coupling_options = &coupling_options,
 176                 .num_coupling_options = ARRAY_SIZE(coupling_options),
 177
 178                 .trigger_sources = &trigger_sources,
 179                 .num_trigger_sources = ARRAY_SIZE(trigger_sources),
 180
 181                 .trigger_slopes = &scope_trigger_slopes,
 182                 .num_trigger_slopes = ARRAY_SIZE(scope_trigger_slopes),
 183
 184                 .timebases = &timebases,
 185                 .num_timebases = ARRAY_SIZE(timebases),
 186
 187                 .vdivs = &vdivs,
 188                 .num_vdivs = ARRAY_SIZE(vdivs),
 189
 190                 .num_xdivs = 10,
 191                 .num_ydivs = 8,
 192         },
 193 };
 194
 195 static void scope_state_dump(const struct scope_config *config,
 196                 struct scope_state *state)
 197 {
 198         unsigned int i;
 199         char *tmp;
 200
 201         for (i = 0; i < config->analog_channels; i++) {
 202                 tmp = sr_voltage_string((*config->vdivs)[state->analog_channels[i].vdiv][0],
 203                                 (*config->vdivs)[state->analog_channels[i].vdiv][1]);
 204                 sr_info("State of analog channel %d -> %s : %s (coupling) %s (vdiv) %2.2e (offset)",
 205                                 i + 1, state->analog_channels[i].state ? "On" : "Off",
 206                                 (*config->coupling_options)[state->analog_channels[i].coupling],
 207                                 tmp, state->analog_channels[i].vertical_offset);
 208         }
 209
 210         tmp = sr_period_string((*config->timebases)[state->timebase][0],
 211                         (*config->timebases)[state->timebase][1]);
 212         sr_info("Current timebase: %s", tmp);
 213         g_free(tmp);
 214
 215         tmp = sr_samplerate_string(state->sample_rate);
 216         sr_info("Current samplerate: %s", tmp);
 217         g_free(tmp);
 218
 219         sr_info("Current trigger: %s (source), %s (slope) %.2f (offset)",
 220                         (*config->trigger_sources)[state->trigger_source],
 221                         (*config->trigger_slopes)[state->trigger_slope],
 222                         state->horiz_triggerpos);
 223 }
 224
 225 static int scope_state_get_array_option(const char *resp,
 226                 const char *(*array)[], unsigned int n, int *result)
 227 {
 228         unsigned int i;
 229
 230         for (i = 0; i < n; i++) {
 231                 if (!g_strcmp0(resp, (*array)[i])) {
 232                         *result = i;
 233                         return SR_OK;
 234                 }
 235         }
 236
 237         return SR_ERR;
 238 }
 239
 240 /**
 241  * This function takes a value of the form "2.000E-03" and returns the index
 242  * of an array where a matching pair was found.
 243  *
 244  * @param value The string to be parsed.
 245  * @param array The array of s/f pairs.
 246  * @param array_len The number of pairs in the array.
 247  * @param result The index at which a matching pair was found.
 248  *
 249  * @return SR_ERR on any parsing error, SR_OK otherwise.
 250  */
 251 static int array_float_get(gchar *value, const uint64_t array[][2],
 252                 int array_len, unsigned int *result)
 253 {
 254         struct sr_rational rval;
 255         struct sr_rational aval;
 256
 257         if (sr_parse_rational(value, &rval) != SR_OK)
 258                 return SR_ERR;
 259
 260         for (int i = 0; i < array_len; i++) {
 261                 sr_rational_set(&aval, array[i][0], array[i][1]);
 262                 if (sr_rational_eq(&rval, &aval)) {
 263                         *result = i;
 264                         return SR_OK;
 265                 }
 266         }
 267
 268         return SR_ERR;
 269 }
 270
 271 static int analog_channel_state_get(struct sr_scpi_dev_inst *scpi,
 272                 const struct scope_config *config, struct scope_state *state)
 273 {
 274         unsigned int i, j;
 275         char command[MAX_COMMAND_SIZE];
 276         char *tmp_str;
 277
 278         for (i = 0; i < config->analog_channels; i++) {
 279                 g_snprintf(command, sizeof(command), "C%d:TRACE?", i + 1);
 280
 281                 if (sr_scpi_get_bool(scpi, command,
 282                                 &state->analog_channels[i].state) != SR_OK)
 283                         return SR_ERR;
 284
 285                 g_snprintf(command, sizeof(command), "C%d:VDIV?", i + 1);
 286
 287                 if (sr_scpi_get_string(scpi, command, &tmp_str) != SR_OK)
 288                         return SR_ERR;
 289
 290                 if (array_float_get(tmp_str, ARRAY_AND_SIZE(vdivs), &j) != SR_OK) {
 291                         g_free(tmp_str);
 292                         sr_err("Could not determine array index for vertical div scale.");
 293                         return SR_ERR;
 294                 }
 295
 296                 g_free(tmp_str);
 297                 state->analog_channels[i].vdiv = j;
 298
 299                 g_snprintf(command, sizeof(command), "C%d:OFFSET?", i + 1);
 300
 301                 if (sr_scpi_get_float(scpi, command, &state->analog_channels[i].vertical_offset) != SR_OK)
 302                         return SR_ERR;
 303
 304                 g_snprintf(command, sizeof(command), "C%d:COUPLING?", i + 1);
 305
 306                 if (sr_scpi_get_string(scpi, command, &tmp_str) != SR_OK)
 307                         return SR_ERR;
 308
 309
 310                 if (scope_state_get_array_option(tmp_str, config->coupling_options,
 311                                  config->num_coupling_options,
 312                                  &state->analog_channels[i].coupling) != SR_OK)
 313                         return SR_ERR;
 314
 315                 g_free(tmp_str);
 316         }
 317
 318         return SR_OK;
 319 }
 320
 321 SR_PRIV int lecroy_xstream_channel_state_set(const struct sr_dev_inst *sdi,
 322                 const int ch_index, gboolean ch_state)
 323 {
 324         GSList *l;
 325         struct sr_channel *ch;
 326         struct dev_context *devc = NULL;
 327         struct scope_state *state;
 328         char command[MAX_COMMAND_SIZE];
 329         gboolean chan_found;
 330         int result;
 331
 332         result = SR_OK;
 333
 334         devc = sdi->priv;
 335         state = devc->model_state;
 336         chan_found = FALSE;
 337
 338         for (l = sdi->channels; l; l = l->next) {
 339                 ch = l->data;
 340
 341                 switch (ch->type) {
 342                 case SR_CHANNEL_ANALOG:
 343                         if (ch->index == ch_index) {
 344                                 g_snprintf(command, sizeof(command), "C%d:TRACE %s", ch_index + 1,
 345                                                 (ch_state ? "ON" : "OFF"));
 346                                 if ((sr_scpi_send(sdi->conn, command) != SR_OK ||
 347                                                 sr_scpi_get_opc(sdi->conn) != SR_OK)) {
 348                                         result = SR_ERR;
 349                                         break;
 350                                 }
 351
 352                                 ch->enabled = ch_state;
 353                                 state->analog_channels[ch->index].state = ch_state;
 354                                 chan_found = TRUE;
 355                                 break;
 356                         }
 357                         break;
 358                 default:
 359                         result = SR_ERR_NA;
 360                 }
 361         }
 362
 363         if ((result == SR_OK) && !chan_found)
 364                 result = SR_ERR_BUG;
 365
 366         return result;
 367 }
 368
 369 SR_PRIV int lecroy_xstream_update_sample_rate(const struct sr_dev_inst *sdi,
 370                 int num_of_samples)
 371 {
 372         struct dev_context *devc;
 373         struct scope_state *state;
 374         const struct scope_config *config;
 375         double time_div;
 376
 377         devc = sdi->priv;
 378         config = devc->model_config;
 379         state = devc->model_state;
 380
 381         if (sr_scpi_get_double(sdi->conn, "TIME_DIV?", &time_div) != SR_OK)
 382                 return SR_ERR;
 383
 384         state->sample_rate = num_of_samples / (time_div * config->num_xdivs);
 385
 386         return SR_OK;
 387 }
 388
 389 SR_PRIV int lecroy_xstream_state_get(struct sr_dev_inst *sdi)
 390 {
 391         struct dev_context *devc;
 392         struct scope_state *state;
 393         const struct scope_config *config;
 394         unsigned int i;
 395         char *tmp_str, *tmp_str2, *tmpp, *p, *key;
 396         char command[MAX_COMMAND_SIZE];
 397         char *trig_source = NULL;
 398
 399         devc = sdi->priv;
 400         config = devc->model_config;
 401         state = devc->model_state;
 402
 403         sr_info("Fetching scope state");
 404
 405         if (analog_channel_state_get(sdi->conn, config, state) != SR_OK)
 406                 return SR_ERR;
 407
 408         if (sr_scpi_get_string(sdi->conn, "TIME_DIV?", &tmp_str) != SR_OK)
 409                 return SR_ERR;
 410
 411         if (array_float_get(tmp_str, ARRAY_AND_SIZE(timebases), &i) != SR_OK) {
 412                 g_free(tmp_str);
 413                 sr_err("Could not determine array index for timbase scale.");
 414                 return SR_ERR;
 415         }
 416         g_free(tmp_str);
 417         state->timebase = i;
 418
 419         if (sr_scpi_get_string(sdi->conn, "TRIG_SELECT?", &tmp_str) != SR_OK)
 420                 return SR_ERR;
 421
 422         key = tmpp = NULL;
 423         tmp_str2 = tmp_str;
 424         i = 0;
 425         while ((p = strtok_r(tmp_str2, ",", &tmpp))) {
 426                 tmp_str2 = NULL;
 427                 if (i == 0) {
 428                         /* trigger type */
 429                 } else if (i & 1) {
 430                         key = p;
 431                         /* key */
 432                 } else if (!(i & 1)) {
 433                         if (!strcmp(key, "SR"))
 434                                 trig_source = p;
 435                 }
 436                 i++;
 437         }
 438         g_free(tmp_str);
 439
 440         if (!trig_source || scope_state_get_array_option(trig_source,
 441                         config->trigger_sources, config->num_trigger_sources,
 442                         &state->trigger_source) != SR_OK)
 443                 return SR_ERR;
 444
 445         g_snprintf(command, sizeof(command), "%s:TRIG_SLOPE?", trig_source);
 446         if (sr_scpi_get_string(sdi->conn, command, &tmp_str) != SR_OK)
 447                 return SR_ERR;
 448
 449         if (scope_state_get_array_option(tmp_str, config->trigger_slopes,
 450                         config->num_trigger_slopes, &state->trigger_slope) != SR_OK)
 451                 return SR_ERR;
 452         g_free(tmp_str);
 453
 454         if (sr_scpi_get_float(sdi->conn, "TRIG_DELAY?", &state->horiz_triggerpos) != SR_OK)
 455                 return SR_ERR;
 456
 457         sr_info("Fetching finished.");
 458
 459         scope_state_dump(config, state);
 460
 461         return SR_OK;
 462 }
 463
 464 static struct scope_state *scope_state_new(const struct scope_config *config)
 465 {
 466         struct scope_state *state;
 467
 468         state = g_malloc0(sizeof(struct scope_state));
 469         state->analog_channels = g_malloc0_n(config->analog_channels,
 470                         sizeof(struct analog_channel_state));
 471         return state;
 472 }
 473
 474 SR_PRIV void lecroy_xstream_state_free(struct scope_state *state)
 475 {
 476         g_free(state->analog_channels);
 477         g_free(state);
 478 }
 479
 480 SR_PRIV int lecroy_xstream_init_device(struct sr_dev_inst *sdi)
 481 {
 482         char command[MAX_COMMAND_SIZE];
 483         int model_index;
 484         unsigned int i, j;
 485         struct sr_channel *ch;
 486         struct dev_context *devc;
 487         gboolean channel_enabled;
 488
 489         devc = sdi->priv;
 490         model_index = -1;
 491
 492         /* Find the exact model. */
 493         for (i = 0; i < ARRAY_SIZE(scope_models); i++) {
 494                 for (j = 0; scope_models[i].name[j]; j++) {
 495                         if (!strcmp(sdi->model, scope_models[i].name[j])) {
 496                                 model_index = i;
 497                                 break;
 498                         }
 499                 }
 500                 if (model_index != -1)
 501                         break;
 502         }
 503
 504         if (model_index == -1) {
 505                 sr_dbg("Unknown LeCroy device, using default config.");
 506                 for (i = 0; i < ARRAY_SIZE(scope_models); i++)
 507                         if (scope_models[i].name[0] == NULL)
 508                                 model_index = i;
 509         }
 510
 511         /* Set the desired response and format modes. */
 512         sr_scpi_send(sdi->conn, "COMM_HEADER OFF");
 513         sr_scpi_send(sdi->conn, "COMM_FORMAT DEF9,WORD,BIN");
 514
 515         devc->analog_groups = g_malloc0(sizeof(struct sr_channel_group*) *
 516                                 scope_models[model_index].analog_channels);
 517
 518         /* Add analog channels. */
 519         for (i = 0; i < scope_models[model_index].analog_channels; i++) {
 520                 g_snprintf(command, sizeof(command), "C%d:TRACE?", i + 1);
 521
 522                 if (sr_scpi_get_bool(sdi->conn, command, &channel_enabled) != SR_OK)
 523                         return SR_ERR;
 524
 525                 g_snprintf(command, sizeof(command), "C%d:VDIV?", i + 1);
 526
 527                 ch = sr_channel_new(sdi, i, SR_CHANNEL_ANALOG, channel_enabled,
 528                         (*scope_models[model_index].analog_names)[i]);
 529
 530                 devc->analog_groups[i] = g_malloc0(sizeof(struct sr_channel_group));
 531
 532                 devc->analog_groups[i]->name = g_strdup(
 533                         (char *)(*scope_models[model_index].analog_names)[i]);
 534                 devc->analog_groups[i]->channels = g_slist_append(NULL, ch);
 535
 536                 sdi->channel_groups = g_slist_append(sdi->channel_groups,
 537                         devc->analog_groups[i]);
 538         }
 539
 540         devc->model_config = &scope_models[model_index];
 541         devc->frame_limit = 0;
 542         devc->model_state = scope_state_new(devc->model_config);
 543
 544         return SR_OK;
 545 }
 546
 547 static int lecroy_waveform_2_x_to_analog(GByteArray *data,
 548                 struct lecroy_wavedesc *desc, struct sr_datafeed_analog *analog)
 549 {
 550         struct sr_analog_encoding *encoding = analog->encoding;
 551         struct sr_analog_meaning *meaning = analog->meaning;
 552         struct sr_analog_spec *spec = analog->spec;
 553         float *data_float;
 554         int16_t *waveform_data;
 555         unsigned int i, num_samples;
 556
 557         data_float = g_malloc(desc->version_2_x.wave_array_count * sizeof(float));
 558         num_samples = desc->version_2_x.wave_array_count;
 559
 560         waveform_data = (int16_t*)(data->data +
 561                 + desc->version_2_x.wave_descriptor_length
 562                 + desc->version_2_x.user_text_len);
 563
 564         for (i = 0; i < num_samples; i++)
 565                 data_float[i] = (float)waveform_data[i]
 566                         * desc->version_2_x.vertical_gain
 567                         + desc->version_2_x.vertical_offset;
 568
 569         analog->data = data_float;
 570         analog->num_samples = num_samples;
 571
 572         encoding->unitsize = sizeof(float);
 573         encoding->is_signed = TRUE;
 574         encoding->is_float = TRUE;
 575         encoding->is_bigendian = FALSE;
 576         encoding->scale.p = 1;
 577         encoding->scale.q = 1;
 578         encoding->offset.p = 0;
 579         encoding->offset.q = 1;
 580
 581         encoding->digits = 6;
 582         encoding->is_digits_decimal = FALSE;
 583
 584         if (strcmp(desc->version_2_x.vertunit, "A")) {
 585                 meaning->mq = SR_MQ_CURRENT;
 586                 meaning->unit = SR_UNIT_AMPERE;
 587         } else {
 588                 /* Default to voltage. */
 589                 meaning->mq = SR_MQ_VOLTAGE;
 590                 meaning->unit = SR_UNIT_VOLT;
 591         }
 592
 593         meaning->mqflags = 0;
 594         spec->spec_digits = 3;
 595
 596         return SR_OK;
 597 }
 598
 599 static int lecroy_waveform_to_analog(GByteArray *data,
 600                 struct sr_datafeed_analog *analog)
 601 {
 602         struct lecroy_wavedesc *desc;
 603
 604         if (data->len < sizeof(struct lecroy_wavedesc))
 605                 return SR_ERR;
 606
 607         desc = (struct lecroy_wavedesc*)data->data;
 608
 609         if (!strncmp(desc->template_name, "LECROY_2_2", 16) ||
 610             !strncmp(desc->template_name, "LECROY_2_3", 16)) {
 611                 return lecroy_waveform_2_x_to_analog(data, desc, analog);
 612         }
 613
 614         sr_err("Waveformat template '%.16s' not supported.", desc->template_name);
 615         return SR_ERR;
 616 }
 617
 618 SR_PRIV int lecroy_xstream_receive_data(int fd, int revents, void *cb_data)
 619 {
 620         char command[MAX_COMMAND_SIZE];
 621         struct sr_channel *ch;
 622         struct sr_dev_inst *sdi;
 623         struct dev_context *devc;
 624         struct scope_state *state;
 625         struct sr_datafeed_packet packet;
 626         GByteArray *data;
 627         struct sr_datafeed_analog analog;
 628         struct sr_analog_encoding encoding;
 629         struct sr_analog_meaning meaning;
 630         struct sr_analog_spec spec;
 631
 632         (void)fd;
 633         (void)revents;
 634
 635         if (!(sdi = cb_data))
 636                 return TRUE;
 637
 638         if (!(devc = sdi->priv))
 639                 return TRUE;
 640
 641         ch = devc->current_channel->data;
 642         state = devc->model_state;
 643
 644         if (ch->type != SR_CHANNEL_ANALOG)
 645                 return SR_ERR;
 646
 647         data = NULL;
 648         if (sr_scpi_get_block(sdi->conn, NULL, &data) != SR_OK) {
 649                 if (data)
 650                         g_byte_array_free(data, TRUE);
 651                 return TRUE;
 652         }
 653
 654         analog.encoding = &encoding;
 655         analog.meaning = &meaning;
 656         analog.spec = &spec;
 657
 658         if (lecroy_waveform_to_analog(data, &analog) != SR_OK)
 659                 return SR_ERR;
 660
 661         if (analog.num_samples == 0) {
 662                 g_free(analog.data);
 663                 g_byte_array_free(data, TRUE);
 664
 665                 /* No data available, we have to acquire data first. */
 666                 g_snprintf(command, sizeof(command), "ARM;WAIT;*OPC;C%d:WAVEFORM?", ch->index + 1);
 667                 sr_scpi_send(sdi->conn, command);
 668
 669                 state->sample_rate = 0;
 670                 return TRUE;
 671         } else {
 672                 /* Update sample rate if needed. */
 673                 if (state->sample_rate == 0)
 674                         if (lecroy_xstream_update_sample_rate(sdi, analog.num_samples) != SR_OK) {
 675                                 g_free(analog.data);
 676                                 g_byte_array_free(data, TRUE);
 677                                 return SR_ERR;
 678                         }
 679         }
 680
 681         /*
 682          * Send "frame begin" packet upon reception of data for the
 683          * first enabled channel.
 684          */
 685         if (devc->current_channel == devc->enabled_channels)
 686                 std_session_send_df_frame_begin(sdi);
 687
 688         meaning.channels = g_slist_append(NULL, ch);
 689         packet.payload = &analog;
 690         packet.type = SR_DF_ANALOG;
 691         sr_session_send(sdi, &packet);
 692
 693         g_byte_array_free(data, TRUE);
 694         data = NULL;
 695
 696         g_slist_free(meaning.channels);
 697         g_free(analog.data);
 698
 699         /*
 700          * Advance to the next enabled channel. When data for all enabled
 701          * channels was received, then flush potentially queued logic data,
 702          * and send the "frame end" packet.
 703          */
 704         if (devc->current_channel->next) {
 705                 devc->current_channel = devc->current_channel->next;
 706                 lecroy_xstream_request_data(sdi);
 707                 return TRUE;
 708         }
 709
 710         std_session_send_df_frame_end(sdi);
 711
 712         /*
 713          * End of frame was reached. Stop acquisition after the specified
 714          * number of frames, or continue reception by starting over at
 715          * the first enabled channel.
 716          */
 717         devc->num_frames++;
 718         if (devc->frame_limit && (devc->num_frames == devc->frame_limit)) {
 719                 sr_dev_acquisition_stop(sdi);
 720         } else {
 721                 devc->current_channel = devc->enabled_channels;
 722
 723                 /* Wait for trigger, then begin fetching data. */
 724                 g_snprintf(command, sizeof(command), "ARM;WAIT;*OPC");
 725                 sr_scpi_send(sdi->conn, command);
 726
 727                 lecroy_xstream_request_data(sdi);
 728         }
 729
 730         return TRUE;
 731 }