/* * This file is part of the libsigrok project. * * Copyright (C) 2012 Martin Ling * Copyright (C) 2013 Bert Vermeulen * Copyright (C) 2013 Mathias Grimmberger * * 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 . */ #include #include #include #include #include #include #include #include #include #include "libsigrok.h" #include "libsigrok-internal.h" #include "protocol.h" /* * This is a unified protocol driver for the DS1000 and DS2000 series. * * DS1000 support tested with a Rigol DS1102D. * * DS2000 support tested with a Rigol DS2072 using firmware version 01.01.00.02. * * The Rigol DS2000 series scopes try to adhere to the IEEE 488.2 (I think) * standard. If you want to read it - it costs real money... * * Every response from the scope has a linefeed appended because the * standard says so. In principle this could be ignored because sending the * next command clears the output queue of the scope. This driver tries to * avoid doing that because it may cause an error being generated inside the * scope and who knows what bugs the firmware has WRT this. * * Waveform data is transferred in a format called "arbitrary block program * data" specified in IEEE 488.2. See Agilents programming manuals for their * 2000/3000 series scopes for a nice description. * * Each data block from the scope has a header, e.g. "#900000001400". * The '#' marks the start of a block. * Next is one ASCII decimal digit between 1 and 9, this gives the number of * ASCII decimal digits following. * Last are the ASCII decimal digits giving the number of bytes (not * samples!) in the block. * * After this header as many data bytes as indicated follow. * * Each data block has a trailing linefeed too. */ static int parse_int(const char *str, int *ret) { char *e; long tmp; errno = 0; tmp = strtol(str, &e, 10); if (e == str || *e != '\0') { sr_dbg("Failed to parse integer: '%s'", str); return SR_ERR; } if (errno) { sr_dbg("Failed to parse integer: '%s', numerical overflow", str); return SR_ERR; } if (tmp > INT_MAX || tmp < INT_MIN) { sr_dbg("Failed to parse integer: '%s', value to large/small", str); return SR_ERR; } *ret = (int)tmp; return SR_OK; } /* Set the next event to wait for in rigol_ds_receive */ static void rigol_ds_set_wait_event(struct dev_context *devc, enum wait_events event) { if (event == WAIT_STOP) devc->wait_status = 2; else devc->wait_status = 1; devc->wait_event = event; } /* * Waiting for a event will return a timeout after 2 to 3 seconds in order * to not block the application. */ static int rigol_ds_event_wait(const struct sr_dev_inst *sdi, char status1, char status2) { char *buf; struct dev_context *devc; time_t start; if (!(devc = sdi->priv)) return SR_ERR; start = time(NULL); /* * Trigger status may return: * "TD" or "T'D" - triggered * "AUTO" - autotriggered * "RUN" - running * "WAIT" - waiting for trigger * "STOP" - stopped */ if (devc->wait_status == 1) { do { if (time(NULL) - start >= 3) { sr_dbg("Timeout waiting for trigger"); return SR_ERR_TIMEOUT; } if (sr_scpi_get_string(sdi->conn, ":TRIG:STAT?", &buf) != SR_OK) return SR_ERR; } while (buf[0] == status1 || buf[0] == status2); devc->wait_status = 2; } if (devc->wait_status == 2) { do { if (time(NULL) - start >= 3) { sr_dbg("Timeout waiting for trigger"); return SR_ERR_TIMEOUT; } if (sr_scpi_get_string(sdi->conn, ":TRIG:STAT?", &buf) != SR_OK) return SR_ERR; } while (buf[0] != status1 && buf[0] != status2); rigol_ds_set_wait_event(devc, WAIT_NONE); } return SR_OK; } /* * For live capture we need to wait for a new trigger event to ensure that * sample data is not returned twice. * * Unfortunately this will never really work because for sufficiently fast * timebases and trigger rates it just can't catch the status changes. * * What would be needed is a trigger event register with autoreset like the * Agilents have. The Rigols don't seem to have anything like this. * * The workaround is to only wait for the trigger when the timebase is slow * enough. Of course this means that for faster timebases sample data can be * returned multiple times, this effect is mitigated somewhat by sleeping * for about one sweep time in that case. */ static int rigol_ds_trigger_wait(const struct sr_dev_inst *sdi) { struct dev_context *devc; long s; if (!(devc = sdi->priv)) return SR_ERR; /* * If timebase < 50 msecs/DIV just sleep about one sweep time except * for really fast sweeps. */ if (devc->timebase < 0.0499) { if (devc->timebase > 0.99e-6) { /* * Timebase * num hor. divs * 85(%) * 1e6(usecs) / 100 * -> 85 percent of sweep time */ s = (devc->timebase * devc->model->series->num_horizontal_divs * 85e6) / 100L; sr_spew("Sleeping for %ld usecs instead of trigger-wait", s); g_usleep(s); } rigol_ds_set_wait_event(devc, WAIT_NONE); return SR_OK; } else { return rigol_ds_event_wait(sdi, 'T', 'A'); } } /* Wait for scope to got to "Stop" in single shot mode */ static int rigol_ds_stop_wait(const struct sr_dev_inst *sdi) { return rigol_ds_event_wait(sdi, 'S', 'S'); } /* Check that a single shot acquisition actually succeeded on the DS2000 */ static int rigol_ds_check_stop(const struct sr_dev_inst *sdi) { struct dev_context *devc; struct sr_probe *probe; int tmp; if (!(devc = sdi->priv)) return SR_ERR; probe = devc->channel_entry->data; if (devc->model->series->protocol <= PROTOCOL_V2) return SR_OK; if (rigol_ds_config_set(sdi, ":WAV:SOUR CHAN%d", probe->index + 1) != SR_OK) return SR_ERR; /* Check that the number of samples will be accepted */ if (rigol_ds_config_set(sdi, ":WAV:POIN %d", devc->analog_frame_size) != SR_OK) return SR_ERR; if (sr_scpi_get_int(sdi->conn, "*ESR?", &tmp) != SR_OK) return SR_ERR; /* * If we get an "Execution error" the scope went from "Single" to * "Stop" without actually triggering. There is no waveform * displayed and trying to download one will fail - the scope thinks * it has 1400 samples (like display memory) and the driver thinks * it has a different number of samples. * * In that case just try to capture something again. Might still * fail in interesting ways. * * Ain't firmware fun? */ if (tmp & 0x10) { sr_warn("Single shot acquisition failed, retrying..."); /* Sleep a bit, otherwise the single shot will often fail */ g_usleep(500000); rigol_ds_config_set(sdi, ":SING"); rigol_ds_set_wait_event(devc, WAIT_STOP); return SR_ERR; } return SR_OK; } /* Wait for enough data becoming available in scope output buffer */ static int rigol_ds_block_wait(const struct sr_dev_inst *sdi) { char *buf; struct dev_context *devc; time_t start; int len; if (!(devc = sdi->priv)) return SR_ERR; if (devc->model->series->protocol >= PROTOCOL_V3) { start = time(NULL); do { if (time(NULL) - start >= 3) { sr_dbg("Timeout waiting for data block"); return SR_ERR_TIMEOUT; } /* * The scope copies data really slowly from sample * memory to its output buffer, so try not to bother * it too much with SCPI requests but don't wait too * long for short sample frame sizes. */ g_usleep(devc->analog_frame_size < 15000 ? 100000 : 1000000); /* "READ,nnnn" (still working) or "IDLE,nnnn" (finished) */ if (sr_scpi_get_string(sdi->conn, ":WAV:STAT?", &buf) != SR_OK) return SR_ERR; if (parse_int(buf + 5, &len) != SR_OK) return SR_ERR; } while (buf[0] == 'R' && len < 1000000); } rigol_ds_set_wait_event(devc, WAIT_NONE); return SR_OK; } /* Send a configuration setting. */ SR_PRIV int rigol_ds_config_set(const struct sr_dev_inst *sdi, const char *format, ...) { struct dev_context *devc = sdi->priv; va_list args; int ret; va_start(args, format); ret = sr_scpi_send_variadic(sdi->conn, format, args); va_end(args); if (ret != SR_OK) return SR_ERR; if (devc->model->series->protocol == PROTOCOL_V2) { /* The DS1000 series needs this stupid delay, *OPC? doesn't work. */ sr_spew("delay %dms", 100); g_usleep(100000); return SR_OK; } else { return sr_scpi_get_opc(sdi->conn); } } /* Start capturing a new frameset */ SR_PRIV int rigol_ds_capture_start(const struct sr_dev_inst *sdi) { struct dev_context *devc; gchar *trig_mode; if (!(devc = sdi->priv)) return SR_ERR; sr_dbg("Starting data capture for frameset %lu of %lu", devc->num_frames + 1, devc->limit_frames); switch (devc->model->series->protocol) { case PROTOCOL_V1: rigol_ds_set_wait_event(devc, WAIT_TRIGGER); break; case PROTOCOL_V2: if (devc->data_source == DATA_SOURCE_LIVE) { if (rigol_ds_config_set(sdi, ":WAV:POIN:MODE NORMAL") != SR_OK) return SR_ERR; rigol_ds_set_wait_event(devc, WAIT_TRIGGER); } else { if (rigol_ds_config_set(sdi, ":STOP") != SR_OK) return SR_ERR; if (rigol_ds_config_set(sdi, ":WAV:POIN:MODE RAW") != SR_OK) return SR_ERR; if (sr_scpi_get_string(sdi->conn, ":TRIG:MODE?", &trig_mode) != SR_OK) return SR_ERR; if (rigol_ds_config_set(sdi, ":TRIG:%s:SWE SING", trig_mode) != SR_OK) return SR_ERR; if (rigol_ds_config_set(sdi, ":RUN") != SR_OK) return SR_ERR; rigol_ds_set_wait_event(devc, WAIT_STOP); } break; case PROTOCOL_V3: if (rigol_ds_config_set(sdi, ":WAV:FORM BYTE") != SR_OK) return SR_ERR; if (devc->data_source == DATA_SOURCE_LIVE) { if (rigol_ds_config_set(sdi, ":WAV:MODE NORM") != SR_OK) return SR_ERR; rigol_ds_set_wait_event(devc, WAIT_TRIGGER); } else { if (rigol_ds_config_set(sdi, ":WAV:MODE RAW") != SR_OK) return SR_ERR; if (rigol_ds_config_set(sdi, ":SING") != SR_OK) return SR_ERR; rigol_ds_set_wait_event(devc, WAIT_STOP); } break; } return SR_OK; } /* Start reading data from the current channel */ SR_PRIV int rigol_ds_channel_start(const struct sr_dev_inst *sdi) { struct dev_context *devc; struct sr_probe *probe; if (!(devc = sdi->priv)) return SR_ERR; probe = devc->channel_entry->data; sr_dbg("Starting reading data from channel %d", probe->index + 1); if (devc->model->series->protocol <= PROTOCOL_V2) { if (probe->type == SR_PROBE_LOGIC) { if (sr_scpi_send(sdi->conn, ":WAV:DATA? DIG") != SR_OK) return SR_ERR; } else { if (sr_scpi_send(sdi->conn, ":WAV:DATA? CHAN%d", probe->index + 1) != SR_OK) return SR_ERR; } rigol_ds_set_wait_event(devc, WAIT_NONE); } else { if (rigol_ds_config_set(sdi, ":WAV:SOUR CHAN%d", probe->index + 1) != SR_OK) return SR_ERR; if (devc->data_source != DATA_SOURCE_LIVE) { if (rigol_ds_config_set(sdi, ":WAV:RES") != SR_OK) return SR_ERR; if (rigol_ds_config_set(sdi, ":WAV:BEG") != SR_OK) return SR_ERR; } } rigol_ds_set_wait_event(devc, WAIT_BLOCK); devc->num_channel_bytes = 0; devc->num_header_bytes = 0; devc->num_block_bytes = 0; return SR_OK; } /* Read the header of a data block */ static int rigol_ds_read_header(struct sr_dev_inst *sdi) { struct sr_scpi_dev_inst *scpi = sdi->conn; struct dev_context *devc = sdi->priv; char *buf = (char *) devc->buffer; size_t header_length; int ret; /* Try to read the hashsign and length digit. */ if (devc->num_header_bytes < 2) { ret = sr_scpi_read_data(scpi, buf + devc->num_header_bytes, 2 - devc->num_header_bytes); if (ret < 0) { sr_err("Read error while reading data header."); return SR_ERR; } devc->num_header_bytes += ret; } if (devc->num_header_bytes < 2) return 0; if (buf[0] != '#' || !isdigit(buf[1]) || buf[1] == '0') { sr_err("Received invalid data block header '%c%c'.", buf[0], buf[1]); return SR_ERR; } header_length = 2 + buf[1] - '0'; /* Try to read the length. */ if (devc->num_header_bytes < header_length) { ret = sr_scpi_read_data(scpi, buf + devc->num_header_bytes, header_length - devc->num_header_bytes); if (ret < 0) { sr_err("Read error while reading data header."); return SR_ERR; } devc->num_header_bytes += ret; } if (devc->num_header_bytes < header_length) return 0; /* Read the data length. */ buf[header_length] = '\0'; if (parse_int(buf + 2, &ret) != SR_OK) { sr_err("Received invalid data block length '%s'.", buf + 2); return -1; } sr_dbg("Received data block header: '%s' -> block length %d", buf, ret); return ret; } SR_PRIV int rigol_ds_receive(int fd, int revents, void *cb_data) { struct sr_dev_inst *sdi; struct sr_scpi_dev_inst *scpi; struct dev_context *devc; struct sr_datafeed_packet packet; struct sr_datafeed_analog analog; struct sr_datafeed_logic logic; double vdiv, offset; int len, i, vref; struct sr_probe *probe; gsize expected_data_bytes; (void)fd; if (!(sdi = cb_data)) return TRUE; if (!(devc = sdi->priv)) return TRUE; scpi = sdi->conn; if (revents == G_IO_IN || revents == 0) { switch(devc->wait_event) { case WAIT_NONE: break; case WAIT_TRIGGER: if (rigol_ds_trigger_wait(sdi) != SR_OK) return TRUE; if (rigol_ds_channel_start(sdi) != SR_OK) return TRUE; return TRUE; case WAIT_BLOCK: if (rigol_ds_block_wait(sdi) != SR_OK) return TRUE; break; case WAIT_STOP: if (rigol_ds_stop_wait(sdi) != SR_OK) return TRUE; if (rigol_ds_check_stop(sdi) != SR_OK) return TRUE; if (rigol_ds_channel_start(sdi) != SR_OK) return TRUE; return TRUE; default: sr_err("BUG: Unknown event target encountered"); } probe = devc->channel_entry->data; expected_data_bytes = probe->type == SR_PROBE_ANALOG ? devc->analog_frame_size : devc->digital_frame_size; if (devc->num_block_bytes == 0) { if (devc->model->series->protocol >= PROTOCOL_V3) if (sr_scpi_send(sdi->conn, ":WAV:DATA?") != SR_OK) return TRUE; if (sr_scpi_read_begin(scpi) != SR_OK) return TRUE; if (devc->format == FORMAT_IEEE488_2) { sr_dbg("New block header expected"); len = rigol_ds_read_header(sdi); if (len == 0) /* Still reading the header. */ return TRUE; if (len == -1) { sr_err("Read error, aborting capture."); packet.type = SR_DF_FRAME_END; sr_session_send(cb_data, &packet); sdi->driver->dev_acquisition_stop(sdi, cb_data); return TRUE; } /* At slow timebases in live capture the DS2072 * sometimes returns "short" data blocks, with * apparently no way to get the rest of the data. * Discard these, the complete data block will * appear eventually. */ if (devc->data_source == DATA_SOURCE_LIVE && (unsigned)len < expected_data_bytes) { sr_dbg("Discarding short data block"); sr_scpi_read_data(scpi, (char *)devc->buffer, len + 1); return TRUE; } devc->num_block_bytes = len; } else { devc->num_block_bytes = expected_data_bytes; } devc->num_block_read = 0; } len = devc->num_block_bytes - devc->num_block_read; if (len > ACQ_BUFFER_SIZE) len = ACQ_BUFFER_SIZE; sr_dbg("Requesting read of %d bytes", len); len = sr_scpi_read_data(scpi, (char *)devc->buffer, len); if (len == -1) { sr_err("Read error, aborting capture."); packet.type = SR_DF_FRAME_END; sr_session_send(cb_data, &packet); sdi->driver->dev_acquisition_stop(sdi, cb_data); return TRUE; } sr_dbg("Received %d bytes.", len); devc->num_block_read += len; if (probe->type == SR_PROBE_ANALOG) { vref = devc->vert_reference[probe->index]; vdiv = devc->vdiv[probe->index] / 25.6; offset = devc->vert_offset[probe->index]; if (devc->model->series->protocol >= PROTOCOL_V3) for (i = 0; i < len; i++) devc->data[i] = ((int)devc->buffer[i] - vref) * vdiv - offset; else for (i = 0; i < len; i++) devc->data[i] = (128 - devc->buffer[i]) * vdiv - offset; analog.probes = g_slist_append(NULL, probe); analog.num_samples = len; analog.data = devc->data; analog.mq = SR_MQ_VOLTAGE; analog.unit = SR_UNIT_VOLT; analog.mqflags = 0; packet.type = SR_DF_ANALOG; packet.payload = &analog; sr_session_send(cb_data, &packet); g_slist_free(analog.probes); } else { logic.length = len; logic.unitsize = 2; logic.data = devc->buffer; packet.type = SR_DF_LOGIC; packet.payload = &logic; sr_session_send(cb_data, &packet); } if (devc->num_block_read == devc->num_block_bytes) { sr_dbg("Block has been completed"); if (devc->model->series->protocol >= PROTOCOL_V3) { /* Discard the terminating linefeed */ sr_scpi_read_data(scpi, (char *)devc->buffer, 1); } if (devc->format == FORMAT_IEEE488_2) { /* Prepare for possible next block */ devc->num_header_bytes = 0; devc->num_block_bytes = 0; if (devc->data_source != DATA_SOURCE_LIVE) rigol_ds_set_wait_event(devc, WAIT_BLOCK); } if (!sr_scpi_read_complete(scpi)) { sr_err("Read should have been completed"); packet.type = SR_DF_FRAME_END; sr_session_send(cb_data, &packet); sdi->driver->dev_acquisition_stop(sdi, cb_data); return TRUE; } devc->num_block_read = 0; } else { sr_dbg("%d of %d block bytes read", devc->num_block_read, devc->num_block_bytes); } devc->num_channel_bytes += len; if (devc->num_channel_bytes < expected_data_bytes) /* Don't have the full data for this channel yet, re-run. */ return TRUE; /* End of data for this channel. */ if (devc->model->series->protocol >= PROTOCOL_V3) { /* Signal end of data download to scope */ if (devc->data_source != DATA_SOURCE_LIVE) /* * This causes a query error, without it switching * to the next channel causes an error. Fun with * firmware... */ rigol_ds_config_set(sdi, ":WAV:END"); } if (probe->type == SR_PROBE_ANALOG && devc->channel_entry->next != NULL) { /* We got the frame for this analog channel, but * there's another analog channel. */ devc->channel_entry = devc->channel_entry->next; rigol_ds_channel_start(sdi); } else { /* Done with all analog channels in this frame. */ if (devc->enabled_digital_probes && devc->channel_entry != devc->enabled_digital_probes) { /* Now we need to get the digital data. */ devc->channel_entry = devc->enabled_digital_probes; rigol_ds_channel_start(sdi); } else { /* Done with this frame. */ packet.type = SR_DF_FRAME_END; sr_session_send(cb_data, &packet); if (++devc->num_frames == devc->limit_frames) { /* Last frame, stop capture. */ sdi->driver->dev_acquisition_stop(sdi, cb_data); } else { /* Get the next frame, starting with the first analog channel. */ if (devc->enabled_analog_probes) devc->channel_entry = devc->enabled_analog_probes; else devc->channel_entry = devc->enabled_digital_probes; rigol_ds_capture_start(sdi); /* Start of next frame. */ packet.type = SR_DF_FRAME_BEGIN; sr_session_send(cb_data, &packet); } } } } return TRUE; } SR_PRIV int rigol_ds_get_dev_cfg(const struct sr_dev_inst *sdi) { struct dev_context *devc; char *t_s, *cmd; unsigned int i; int res; devc = sdi->priv; /* Analog channel state. */ for (i = 0; i < devc->model->analog_channels; i++) { cmd = g_strdup_printf(":CHAN%d:DISP?", i + 1); res = sr_scpi_get_string(sdi->conn, cmd, &t_s); g_free(cmd); if (res != SR_OK) return SR_ERR; devc->analog_channels[i] = !strcmp(t_s, "ON") || !strcmp(t_s, "1"); } sr_dbg("Current analog channel state:"); for (i = 0; i < devc->model->analog_channels; i++) sr_dbg("CH%d %s", i + 1, devc->analog_channels[i] ? "on" : "off"); /* Digital channel state. */ if (devc->model->has_digital) { if (sr_scpi_get_string(sdi->conn, ":LA:DISP?", &t_s) != SR_OK) return SR_ERR; devc->la_enabled = !strcmp(t_s, "ON") ? TRUE : FALSE; sr_dbg("Logic analyzer %s, current digital channel state:", devc->la_enabled ? "enabled" : "disabled"); for (i = 0; i < 16; i++) { cmd = g_strdup_printf(":DIG%d:TURN?", i); res = sr_scpi_get_string(sdi->conn, cmd, &t_s); g_free(cmd); if (res != SR_OK) return SR_ERR; devc->digital_channels[i] = !strcmp(t_s, "ON") ? TRUE : FALSE; g_free(t_s); sr_dbg("D%d: %s", i, devc->digital_channels[i] ? "on" : "off"); } } /* Timebase. */ if (sr_scpi_get_float(sdi->conn, ":TIM:SCAL?", &devc->timebase) != SR_OK) return SR_ERR; sr_dbg("Current timebase %g", devc->timebase); /* Vertical gain. */ for (i = 0; i < devc->model->analog_channels; i++) { cmd = g_strdup_printf(":CHAN%d:SCAL?", i + 1); res = sr_scpi_get_float(sdi->conn, cmd, &devc->vdiv[i]); g_free(cmd); if (res != SR_OK) return SR_ERR; } sr_dbg("Current vertical gain:"); for (i = 0; i < devc->model->analog_channels; i++) sr_dbg("CH%d %g", i + 1, devc->vdiv[i]); sr_dbg("Current vertical reference:"); if (devc->model->series->protocol >= PROTOCOL_V3) { /* Vertical reference - not certain if this is the place to read it. */ for (i = 0; i < devc->model->analog_channels; i++) { if (rigol_ds_config_set(sdi, ":WAV:SOUR CHAN%d", i + 1) != SR_OK) return SR_ERR; if (sr_scpi_get_int(sdi->conn, ":WAV:YREF?", &devc->vert_reference[i]) != SR_OK) return SR_ERR; sr_dbg("CH%d %d", i + 1, devc->vert_reference[i]); } } /* Vertical offset. */ for (i = 0; i < devc->model->analog_channels; i++) { cmd = g_strdup_printf(":CHAN%d:OFFS?", i + 1); res = sr_scpi_get_float(sdi->conn, cmd, &devc->vert_offset[i]); g_free(cmd); if (res != SR_OK) return SR_ERR; } sr_dbg("Current vertical offset:"); for (i = 0; i < devc->model->analog_channels; i++) sr_dbg("CH%d %g", i + 1, devc->vert_offset[i]); /* Coupling. */ for (i = 0; i < devc->model->analog_channels; i++) { cmd = g_strdup_printf(":CHAN%d:COUP?", i + 1); res = sr_scpi_get_string(sdi->conn, cmd, &devc->coupling[i]); g_free(cmd); if (res != SR_OK) return SR_ERR; } sr_dbg("Current coupling:"); for (i = 0; i < devc->model->analog_channels; i++) sr_dbg("CH%d %s", i + 1, devc->coupling[i]); /* Trigger source. */ if (sr_scpi_get_string(sdi->conn, ":TRIG:EDGE:SOUR?", &devc->trigger_source) != SR_OK) return SR_ERR; sr_dbg("Current trigger source %s", devc->trigger_source); /* Horizontal trigger position. */ if (sr_scpi_get_float(sdi->conn, ":TIM:OFFS?", &devc->horiz_triggerpos) != SR_OK) return SR_ERR; sr_dbg("Current horizontal trigger position %g", devc->horiz_triggerpos); /* Trigger slope. */ if (sr_scpi_get_string(sdi->conn, ":TRIG:EDGE:SLOP?", &devc->trigger_slope) != SR_OK) return SR_ERR; sr_dbg("Current trigger slope %s", devc->trigger_slope); return SR_OK; }