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 uint32_t devopts[] = {
  78         SR_CONF_OSCILLOSCOPE,
  79         SR_CONF_LIMIT_FRAMES | SR_CONF_GET | SR_CONF_SET,
  80         SR_CONF_TRIGGER_SOURCE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
  81         SR_CONF_TIMEBASE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
  82         SR_CONF_NUM_HDIV | SR_CONF_GET,
  83         SR_CONF_TRIGGER_SLOPE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
  84         SR_CONF_HORIZ_TRIGGERPOS | SR_CONF_GET | SR_CONF_SET,
  85         SR_CONF_SAMPLERATE | SR_CONF_GET,
  86 };
  87
  88 static const uint32_t analog_devopts[] = {
  89         SR_CONF_NUM_VDIV | SR_CONF_GET,
  90         SR_CONF_COUPLING | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
  91         SR_CONF_VDIV | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
  92 };
  93
  94 static const char *coupling_options[] = {
  95         "A1M", // AC with 1 MOhm termination
  96         "D50", // DC with 50 Ohm termination
  97         "D1M", // DC with 1 MOhm termination
  98         "GND",
  99         "OVL",
 100         NULL,
 101 };
 102
 103 static const char *scope_trigger_slopes[] = {
 104         "POS",
 105         "NEG",
 106         NULL,
 107 };
 108
 109 static const char *trigger_sources[] = {
 110         "C1",
 111         "C2",
 112         "C3",
 113         "C4",
 114         "LINE",
 115         "EXT",
 116         NULL,
 117 };
 118
 119 static const struct sr_rational timebases[] = {
 120         /* picoseconds */
 121         { 20, 1000000000000 },
 122         { 50, 1000000000000 },
 123         { 100, 1000000000000 },
 124         { 200, 1000000000000 },
 125         { 500, 1000000000000 },
 126         /* nanoseconds */
 127         { 1, 1000000000 },
 128         { 2, 1000000000 },
 129         { 5, 1000000000 },
 130         { 10, 1000000000 },
 131         { 20, 1000000000 },
 132         { 50, 1000000000 },
 133         { 100, 1000000000 },
 134         { 200, 1000000000 },
 135         { 500, 1000000000 },
 136         /* microseconds */
 137         { 1, 1000000 },
 138         { 2, 1000000 },
 139         { 5, 1000000 },
 140         { 10, 1000000 },
 141         { 20, 1000000 },
 142         { 50, 1000000 },
 143         { 100, 1000000 },
 144         { 200, 1000000 },
 145         { 500, 1000000 },
 146         /* milliseconds */
 147         { 1, 1000 },
 148         { 2, 1000 },
 149         { 5, 1000 },
 150         { 10, 1000 },
 151         { 20, 1000 },
 152         { 50, 1000 },
 153         { 100, 1000 },
 154         { 200, 1000 },
 155         { 500, 1000 },
 156         /* seconds */
 157         { 1, 1 },
 158         { 2, 1 },
 159         { 5, 1 },
 160         { 10, 1 },
 161         { 20, 1 },
 162         { 50, 1 },
 163         { 100, 1 },
 164         { 200, 1 },
 165         { 500, 1 },
 166         { 1000, 1 },
 167 };
 168
 169 static const struct sr_rational vdivs[] = {
 170         /* millivolts */
 171         { 1, 1000 },
 172         { 2, 1000 },
 173         { 5, 1000 },
 174         { 10, 1000 },
 175         { 20, 1000 },
 176         { 50, 1000 },
 177         { 100, 1000 },
 178         { 200, 1000 },
 179         { 500, 1000 },
 180         /* volts */
 181         { 1, 1 },
 182         { 2, 1 },
 183         { 5, 1 },
 184         { 10, 1 },
 185         { 20, 1 },
 186         { 50, 1 },
 187 };
 188
 189 static const char *scope_analog_channel_names[] = {
 190         "CH1",
 191         "CH2",
 192         "CH3",
 193         "CH4",
 194 };
 195
 196 static const struct scope_config scope_models[] = {
 197         {
 198                 .name = { "WP7000", "WP7100", "WP7200", "WP7300" },
 199
 200                 .analog_channels = 4,
 201                 .analog_names = &scope_analog_channel_names,
 202
 203                 .devopts = &devopts,
 204                 .num_devopts = ARRAY_SIZE(devopts),
 205
 206                 .analog_devopts = &analog_devopts,
 207                 .num_analog_devopts = ARRAY_SIZE(analog_devopts),
 208
 209                 .coupling_options = &coupling_options,
 210                 .trigger_sources = &trigger_sources,
 211                 .trigger_slopes = &scope_trigger_slopes,
 212
 213                 .timebases = timebases,
 214                 .num_timebases = ARRAY_SIZE(timebases),
 215
 216                 .vdivs = vdivs,
 217                 .num_vdivs = ARRAY_SIZE(vdivs),
 218
 219                 .num_xdivs = 10,
 220                 .num_ydivs = 8,
 221         },
 222 };
 223
 224 static void scope_state_dump(const struct scope_config *config,
 225                              struct scope_state *state)
 226 {
 227         unsigned int i;
 228         char *tmp;
 229
 230         for (i = 0; i < config->analog_channels; i++) {
 231                 tmp = sr_voltage_string(config->vdivs[state->analog_channels[i].vdiv].p,
 232                                         config->vdivs[state->analog_channels[i].vdiv].q);
 233                 sr_info("State of analog channel %d -> %s : %s (coupling) %s (vdiv) %2.2e (offset)",
 234                         i + 1, state->analog_channels[i].state ? "On" : "Off",
 235                         (*config->coupling_options)[state->analog_channels[i].coupling],
 236                         tmp, state->analog_channels[i].vertical_offset);
 237         }
 238
 239         tmp = sr_period_string(config->timebases[state->timebase].p,
 240                                 config->timebases[state->timebase].q);
 241         sr_info("Current timebase: %s", tmp);
 242         g_free(tmp);
 243
 244         tmp = sr_samplerate_string(state->sample_rate);
 245         sr_info("Current samplerate: %s", tmp);
 246         g_free(tmp);
 247
 248         sr_info("Current trigger: %s (source), %s (slope) %.2f (offset)",
 249                 (*config->trigger_sources)[state->trigger_source],
 250                 (*config->trigger_slopes)[state->trigger_slope],
 251                 state->horiz_triggerpos);
 252 }
 253
 254 static int scope_state_get_array_option(const char *resp,
 255                                         const char *(*array)[], int *result)
 256 {
 257         unsigned int i;
 258
 259         for (i = 0; (*array)[i]; i++) {
 260                 if (!g_strcmp0(resp, (*array)[i])) {
 261                         *result = i;
 262                         return SR_OK;
 263                 }
 264         }
 265
 266         return SR_ERR;
 267 }
 268
 269 /**
 270  * This function takes a value of the form "2.000E-03" and returns the index
 271  * of an array where a matching pair was found.
 272  *
 273  * @param value The string to be parsed.
 274  * @param array The array of s/f pairs.
 275  * @param array_len The number of pairs in the array.
 276  * @param result The index at which a matching pair was found.
 277  *
 278  * @return SR_ERR on any parsing error, SR_OK otherwise.
 279  */
 280 static int array_float_get(gchar *value, const struct sr_rational *aval,
 281                 int array_len, unsigned int *result)
 282 {
 283         struct sr_rational rval;
 284
 285         if (sr_parse_rational(value, &rval) != SR_OK)
 286                 return SR_ERR;
 287
 288         for (int i = 0; i < array_len; i++) {
 289                 if (sr_rational_eq(&rval, aval + i)) {
 290                         *result = i;
 291                         return SR_OK;
 292                 }
 293         }
 294
 295         return SR_ERR;
 296 }
 297
 298 static int analog_channel_state_get(struct sr_scpi_dev_inst *scpi,
 299                                     const struct scope_config *config,
 300                                     struct scope_state *state)
 301 {
 302         unsigned int i, j;
 303         char command[MAX_COMMAND_SIZE];
 304         char *tmp_str;
 305
 306         for (i = 0; i < config->analog_channels; i++) {
 307                 g_snprintf(command, sizeof(command), "C%d:TRACE?", i + 1);
 308
 309                 if (sr_scpi_get_bool(scpi, command,
 310                                 &state->analog_channels[i].state) != SR_OK)
 311                         return SR_ERR;
 312
 313                 g_snprintf(command, sizeof(command), "C%d:VDIV?", i + 1);
 314
 315                 if (sr_scpi_get_string(scpi, command, &tmp_str) != SR_OK)
 316                         return SR_ERR;
 317
 318                 if (array_float_get(tmp_str, vdivs, ARRAY_SIZE(vdivs), &j) != SR_OK) {
 319                         g_free(tmp_str);
 320                         sr_err("Could not determine array index for vertical div scale.");
 321                         return SR_ERR;
 322                 }
 323
 324                 g_free(tmp_str);
 325                 state->analog_channels[i].vdiv = j;
 326
 327                 g_snprintf(command, sizeof(command), "C%d:OFFSET?", i + 1);
 328
 329                 if (sr_scpi_get_float(scpi, command, &state->analog_channels[i].vertical_offset) != SR_OK)
 330                         return SR_ERR;
 331
 332                 g_snprintf(command, sizeof(command), "C%d:COUPLING?", i + 1);
 333
 334                 if (sr_scpi_get_string(scpi, command, &tmp_str) != SR_OK)
 335                         return SR_ERR;
 336
 337
 338                 if (scope_state_get_array_option(tmp_str, config->coupling_options,
 339                                  &state->analog_channels[i].coupling) != SR_OK)
 340                         return SR_ERR;
 341
 342                 g_free(tmp_str);
 343         }
 344
 345         return SR_OK;
 346 }
 347
 348 SR_PRIV int lecroy_xstream_update_sample_rate(const struct sr_dev_inst *sdi)
 349 {
 350         struct dev_context *devc;
 351         struct scope_state *state;
 352         const struct scope_config *config;
 353         float memsize, timediv;
 354
 355         devc = sdi->priv;
 356         state = devc->model_state;
 357         config = devc->model_config;
 358
 359         if (sr_scpi_get_float(sdi->conn, "MEMORY_SIZE?", &memsize) != SR_OK)
 360                 return SR_ERR;
 361
 362         if (sr_scpi_get_float(sdi->conn, "TIME_DIV?", &timediv) != SR_OK)
 363                 return SR_ERR;
 364
 365         state->sample_rate = 1 / ((timediv * config->num_xdivs) / memsize);
 366
 367         return SR_OK;
 368 }
 369
 370 SR_PRIV int lecroy_xstream_state_get(struct sr_dev_inst *sdi)
 371 {
 372         struct dev_context *devc;
 373         struct scope_state *state;
 374         const struct scope_config *config;
 375         unsigned int i;
 376         char *tmp_str, *tmp_str2, *tmpp, *p, *key;
 377         char command[MAX_COMMAND_SIZE];
 378         char *trig_source = NULL;
 379
 380         devc = sdi->priv;
 381         config = devc->model_config;
 382         state = devc->model_state;
 383
 384         sr_info("Fetching scope state");
 385
 386         if (analog_channel_state_get(sdi->conn, config, state) != SR_OK)
 387                 return SR_ERR;
 388
 389         if (sr_scpi_get_string(sdi->conn, "TIME_DIV?", &tmp_str) != SR_OK)
 390                 return SR_ERR;
 391
 392         if (array_float_get(tmp_str, timebases, ARRAY_SIZE(timebases), &i) != SR_OK) {
 393                 g_free(tmp_str);
 394                 sr_err("Could not determine array index for timbase scale.");
 395                 return SR_ERR;
 396         }
 397         g_free(tmp_str);
 398         state->timebase = i;
 399
 400         if (sr_scpi_get_string(sdi->conn, "TRIG_SELECT?", &tmp_str) != SR_OK)
 401                 return SR_ERR;
 402
 403         key = tmpp = NULL;
 404         tmp_str2 = tmp_str;
 405         i = 0;
 406         while ((p = strtok_r(tmp_str2, ",", &tmpp))) {
 407                 tmp_str2 = NULL;
 408                 if (i == 0) {
 409                         /* trigger type */
 410                 } else if (i & 1) {
 411                         key = p;
 412                         /* key */
 413                 } else if (!(i & 1)) {
 414                         if (!strcmp(key, "SR"))
 415                                 trig_source = p;
 416                 }
 417                 i++;
 418         }
 419
 420         if (!trig_source || scope_state_get_array_option(trig_source, config->trigger_sources, &state->trigger_source) != SR_OK)
 421                 return SR_ERR;
 422
 423         g_snprintf(command, sizeof(command), "%s:TRIG_SLOPE?", trig_source);
 424         if (sr_scpi_get_string(sdi->conn, command, &tmp_str) != SR_OK)
 425                 return SR_ERR;
 426
 427         if (scope_state_get_array_option(tmp_str,
 428                 config->trigger_slopes, &state->trigger_slope) != SR_OK)
 429                 return SR_ERR;
 430
 431         if (sr_scpi_get_float(sdi->conn, "TRIG_DELAY?", &state->horiz_triggerpos) != SR_OK)
 432                 return SR_ERR;
 433
 434         if (lecroy_xstream_update_sample_rate(sdi) != SR_OK)
 435                 return SR_ERR;
 436
 437         sr_info("Fetching finished.");
 438
 439         scope_state_dump(config, state);
 440
 441         return SR_OK;
 442 }
 443
 444 static struct scope_state *scope_state_new(const struct scope_config *config)
 445 {
 446         struct scope_state *state;
 447
 448         state = g_malloc0(sizeof(struct scope_state));
 449         state->analog_channels = g_malloc0_n(config->analog_channels,
 450                         sizeof(struct analog_channel_state));
 451         return state;
 452 }
 453
 454 SR_PRIV void lecroy_xstream_state_free(struct scope_state *state)
 455 {
 456         g_free(state->analog_channels);
 457         g_free(state);
 458 }
 459
 460 SR_PRIV int lecroy_xstream_init_device(struct sr_dev_inst *sdi)
 461 {
 462         char command[MAX_COMMAND_SIZE];
 463         int model_index;
 464         unsigned int i, j;
 465         struct sr_channel *ch;
 466         struct dev_context *devc;
 467         gboolean channel_enabled;
 468
 469         devc = sdi->priv;
 470         model_index = -1;
 471
 472         /* Find the exact model. */
 473         for (i = 0; i < ARRAY_SIZE(scope_models); i++) {
 474                 for (j = 0; scope_models[i].name[j]; j++) {
 475                         if (!strcmp(sdi->model, scope_models[i].name[j])) {
 476                                 model_index = i;
 477                                 break;
 478                         }
 479                 }
 480                 if (model_index != -1)
 481                         break;
 482         }
 483
 484         if (model_index == -1) {
 485                 sr_dbg("Unsupported LeCroy device.");
 486                 return SR_ERR_NA;
 487         }
 488
 489         devc->analog_groups = g_malloc0(sizeof(struct sr_channel_group*) *
 490                                 scope_models[model_index].analog_channels);
 491
 492         /* Add analog channels. */
 493         for (i = 0; i < scope_models[model_index].analog_channels; i++) {
 494                 g_snprintf(command, sizeof(command), "C%d:TRACE?", i + 1);
 495
 496                 if (sr_scpi_get_bool(sdi->conn, command, &channel_enabled) != SR_OK)
 497                         return SR_ERR;
 498
 499                 g_snprintf(command, sizeof(command), "C%d:VDIV?", i + 1);
 500
 501                 ch = sr_channel_new(sdi, i, SR_CHANNEL_ANALOG, channel_enabled,
 502                            (*scope_models[model_index].analog_names)[i]);
 503
 504                 devc->analog_groups[i] = g_malloc0(sizeof(struct sr_channel_group));
 505
 506                 devc->analog_groups[i]->name = g_strdup(
 507                         (char *)(*scope_models[model_index].analog_names)[i]);
 508                 devc->analog_groups[i]->channels = g_slist_append(NULL, ch);
 509
 510                 sdi->channel_groups = g_slist_append(sdi->channel_groups,
 511                                                    devc->analog_groups[i]);
 512         }
 513
 514         devc->model_config = &scope_models[model_index];
 515         devc->frame_limit = 0;
 516
 517         if (!(devc->model_state = scope_state_new(devc->model_config)))
 518                 return SR_ERR_MALLOC;
 519
 520         /* Set the desired response mode. */
 521         sr_scpi_send(sdi->conn, "COMM_HEADER OFF,WORD,BIN");
 522
 523         return SR_OK;
 524 }
 525
 526 static int lecroy_waveform_2_x_to_analog(GByteArray *data,
 527                                          struct lecroy_wavedesc *desc,
 528                                          struct sr_datafeed_analog *analog)
 529 {
 530         struct sr_analog_encoding *encoding = analog->encoding;
 531         struct sr_analog_meaning *meaning = analog->meaning;
 532         struct sr_analog_spec *spec = analog->spec;
 533         float *data_float;
 534         int16_t *waveform_data;
 535         unsigned int i, num_samples;
 536
 537         data_float = g_malloc(desc->version_2_x.wave_array_count * sizeof(float));
 538         num_samples = desc->version_2_x.wave_array_count;
 539
 540         waveform_data = (int16_t *)(data->data +
 541                                     + desc->version_2_x.wave_descriptor_length
 542                                     + desc->version_2_x.user_text_len);
 543
 544         for (i = 0; i < num_samples; i++)
 545                 data_float[i] = (float)waveform_data[i]
 546                         * desc->version_2_x.vertical_gain
 547                         + desc->version_2_x.vertical_offset;
 548
 549         analog->data = data_float;
 550         analog->num_samples = num_samples;
 551
 552         encoding->unitsize = sizeof(float);
 553         encoding->is_signed = TRUE;
 554         encoding->is_float = TRUE;
 555         encoding->is_bigendian = FALSE;
 556         encoding->scale.p = 1;
 557         encoding->scale.q = 1;
 558         encoding->offset.p = 0;
 559         encoding->offset.q = 1;
 560
 561         encoding->digits = 6;
 562         encoding->is_digits_decimal = FALSE;
 563
 564         if (strcmp(desc->version_2_x.vertunit, "A")) {
 565                 meaning->mq = SR_MQ_CURRENT;
 566                 meaning->unit = SR_UNIT_AMPERE;
 567         } else {
 568                 /* Default to voltage. */
 569                 meaning->mq = SR_MQ_VOLTAGE;
 570                 meaning->unit = SR_UNIT_VOLT;
 571         }
 572
 573         meaning->mqflags = 0;
 574         spec->spec_digits = 3;
 575
 576         return SR_OK;
 577 }
 578
 579 static int lecroy_waveform_to_analog(GByteArray *data,
 580                                      struct sr_datafeed_analog *analog)
 581 {
 582         struct lecroy_wavedesc *desc;
 583
 584         if (data->len < sizeof(struct lecroy_wavedesc))
 585                 return SR_ERR;
 586
 587         desc = (struct lecroy_wavedesc *)data->data;
 588
 589         if (!strncmp(desc->template_name, "LECROY_2_2", 16) ||
 590             !strncmp(desc->template_name, "LECROY_2_3", 16)) {
 591                 return lecroy_waveform_2_x_to_analog(data, desc, analog);
 592         }
 593
 594         sr_err("Waveformat template '%.16s' not supported.",
 595                desc->template_name);
 596
 597         return SR_ERR;
 598 }
 599
 600 SR_PRIV int lecroy_xstream_receive_data(int fd, int revents, void *cb_data)
 601 {
 602         struct sr_channel *ch;
 603         struct sr_dev_inst *sdi;
 604         struct dev_context *devc;
 605         struct sr_datafeed_packet packet;
 606         GByteArray *data;
 607         struct sr_datafeed_analog analog;
 608         struct sr_analog_encoding encoding;
 609         struct sr_analog_meaning meaning;
 610         struct sr_analog_spec spec;
 611         char buf[8];
 612
 613         (void)fd;
 614         (void)revents;
 615
 616         data = NULL;
 617
 618         if (!(sdi = cb_data))
 619                 return TRUE;
 620
 621         if (!(devc = sdi->priv))
 622                 return TRUE;
 623
 624         ch = devc->current_channel->data;
 625
 626         /*
 627          * Send "frame begin" packet upon reception of data for the
 628          * first enabled channel.
 629          */
 630         if (devc->current_channel == devc->enabled_channels) {
 631                 packet.type = SR_DF_FRAME_BEGIN;
 632                 sr_session_send(sdi, &packet);
 633         }
 634
 635         if (ch->type != SR_CHANNEL_ANALOG)
 636                 return SR_ERR;
 637
 638         /* Pass on the received data of the channel(s). */
 639         if (sr_scpi_read_data(sdi->conn, buf, 4) != 4) {
 640                 sr_err("Reading header failed.");
 641                 return TRUE;
 642         }
 643
 644         if (sr_scpi_get_block(sdi->conn, NULL, &data) != SR_OK) {
 645                 if (data)
 646                         g_byte_array_free(data, TRUE);
 647                 return TRUE;
 648         }
 649
 650         analog.encoding = &encoding;
 651         analog.meaning = &meaning;
 652         analog.spec = &spec;
 653
 654         if (lecroy_waveform_to_analog(data, &analog) != SR_OK)
 655                 return SR_ERR;
 656
 657         meaning.channels = g_slist_append(NULL, ch);
 658         packet.payload = &analog;
 659         packet.type = SR_DF_ANALOG;
 660         sr_session_send(sdi, &packet);
 661
 662         g_byte_array_free(data, TRUE);
 663         data = NULL;
 664
 665         g_slist_free(meaning.channels);
 666         g_free(analog.data);
 667
 668         /*
 669          * Advance to the next enabled channel. When data for all enabled
 670          * channels was received, then flush potentially queued logic data,
 671          * and send the "frame end" packet.
 672          */
 673         if (devc->current_channel->next) {
 674                 devc->current_channel = devc->current_channel->next;
 675                 lecroy_xstream_request_data(sdi);
 676                 return TRUE;
 677         }
 678
 679         packet.type = SR_DF_FRAME_END;
 680         sr_session_send(sdi, &packet);
 681
 682         /*
 683          * End of frame was reached. Stop acquisition after the specified
 684          * number of frames, or continue reception by starting over at
 685          * the first enabled channel.
 686          */
 687         if (++devc->num_frames == devc->frame_limit) {
 688                 sdi->driver->dev_acquisition_stop(sdi);
 689         } else {
 690                 devc->current_channel = devc->enabled_channels;
 691                 lecroy_xstream_request_data(sdi);
 692         }
 693
 694         return TRUE;
 695 }