]> sigrok.org Git - libsigrok.git/commitdiff
scpi: Add helper functions for SCPI communication.
authorpoljar (Damir Jelić) <redacted>
Tue, 29 Oct 2013 11:15:47 +0000 (12:15 +0100)
committerUwe Hermann <redacted>
Tue, 3 Dec 2013 14:10:00 +0000 (15:10 +0100)
The Standard Commands for Programmable Instruments (SCPI) defines a standard
for syntax and commands to use in controlling programmable test and measurement
devices.

SCPI documentation:
http://www.ivifoundation.org/docs/scpi-99.pdf

This patch adds helper functions for sending SCPI commands, reading a SCPI
response and reading and parsing a SCPI "*IDN?" response.

hardware/common/Makefile.am
hardware/common/scpi.c [new file with mode: 0644]
libsigrok-internal.h

index de8f06c168baeaea23168a7287ed8ff4f18d3a3f..716436b75babb5f6ca3c5dcb9e0f9cc402a26c4f 100644 (file)
@@ -25,7 +25,7 @@ noinst_LTLIBRARIES = libsigrok_hw_common.la
 libsigrok_hw_common_la_SOURCES =
 
 if NEED_SERIAL
-libsigrok_hw_common_la_SOURCES += serial.c
+libsigrok_hw_common_la_SOURCES += serial.c scpi.c
 endif
 
 if NEED_USB
diff --git a/hardware/common/scpi.c b/hardware/common/scpi.c
new file mode 100644 (file)
index 0000000..d8f5a2b
--- /dev/null
@@ -0,0 +1,219 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2013 poljar (Damir Jelić) <poljarinho@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/>.
+ */
+
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+
+#include <glib.h>
+#include <string.h>
+
+/* Message logging helpers with subsystem-specific prefix string. */
+#define LOG_PREFIX "scpi: "
+#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
+#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
+#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
+#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
+#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
+
+#define SCPI_READ_RETRIES 100
+#define SCPI_READ_RETRY_TIMEOUT 10000
+
+/**
+ * Send a SCPI command.
+ *
+ * @param serial Previously initialized serial port structure.
+ * @param command The SCPI command to send to the device.
+ *
+ * @return SR_OK on success, SR_ERR on failure.
+ */
+SR_PRIV int sr_scpi_send(struct sr_serial_dev_inst *serial,
+                        const char *command)
+{
+       int len;
+       int out;
+       gchar *terminated_command;
+
+       terminated_command = g_strconcat(command, "\n", NULL);
+       len = strlen(terminated_command);
+
+       out = serial_write(serial, terminated_command,
+                          strlen(terminated_command));
+
+       g_free(terminated_command);
+
+       if (out != len) {
+               sr_dbg("Only sent %d/%d bytes of SCPI command: '%s'.", out,
+                      len, command);
+               return SR_ERR;
+       }
+
+       sr_spew("Successfully sent SCPI command: '%s'.", command);
+
+       return SR_OK;
+}
+
+/**
+ * Send a SCPI command, receive the reply and store the reply in scpi_response.
+ *
+ * @param serial Previously initialized serial port structure.
+ * @param command The SCPI command to send to the device (can be NULL).
+ * @param scpi_response Pointer where to store the scpi response.
+ *
+ * @return SR_OK upon fetching a full SCPI response, SR_ERR upon fetching a
+ * incomplete or no response. The allocated response must be freed by the caller
+ * in the case of a full response as well in the case of an incomplete.
+ */
+SR_PRIV int sr_scpi_get_string(struct sr_serial_dev_inst *serial,
+                                const char *command, char **scpi_response)
+{
+       int len;
+       int ret;
+       char buf[256];
+       unsigned int i;
+       GString *response;
+
+       if (command)
+               if (sr_scpi_send(serial, command) != SR_OK)
+                       return SR_ERR;
+
+       response = g_string_sized_new(1024);
+
+       for (i = 0; i <= SCPI_READ_RETRIES; i++) {
+               while ((len = serial_read(serial, buf, sizeof(buf))) > 0)
+                       response = g_string_append_len(response, buf, len);
+
+               if (response->len > 0 &&
+                   response->str[response->len-1] == '\n') {
+                       sr_spew("Fetched full SCPI response");
+                       break;
+               }
+
+               g_usleep(SCPI_READ_RETRY_TIMEOUT);
+       }
+
+       if (response->len == 0) {
+               sr_dbg("No SCPI response received");
+               g_string_free(response, TRUE);
+               *scpi_response = NULL;
+               return SR_ERR;
+
+       } else if (response->str[response->len-1] == '\n') {
+               /*
+                * The SCPI response contains a LF ('\n') at the end and we
+                * don't need this so replace it with a '\0' and decrement
+                * the length.
+                */
+               response->str[--response->len] = '\0';
+               ret = SR_OK;
+
+       } else {
+               sr_warn("Incomplete SCPI response received!");
+               ret = SR_ERR;
+       }
+
+       /* Minor optimization: steal the string instead of copying. */
+       *scpi_response = response->str;
+
+       /* A SCPI response can be quite large, print at most 50 characters */
+       sr_dbg("SCPI response for command %s received (length %d): '%.50s'",
+              command, response->len, response->str);
+
+       g_string_free(response, FALSE);
+
+       return ret;
+}
+
+/**
+ * Send the *IDN? SCPI command, receive the reply, parse it and store the
+ * reply as a sr_scpi_hw_info structure in the supplied scpi_response pointer.
+ *
+ * @param serial Previously initialized serial port structure.
+ * @param scpi_response Pointer where to store the hw_info structure.
+ *
+ * @return SR_OK upon success, SR_ERR on failure.
+ * The hw_info structure must be freed by the caller with sr_scpi_hw_info_free().
+ */
+SR_PRIV int sr_scpi_get_hw_id(struct sr_serial_dev_inst *serial,
+                             struct sr_scpi_hw_info **scpi_response)
+{
+       int num_tokens;
+       char *response;
+       gchar **tokens;
+
+       struct sr_scpi_hw_info *hw_info;
+
+       response = NULL;
+       tokens = NULL;
+
+       if (sr_scpi_get_string(serial, SCPI_CMD_IDN, &response) != SR_OK)
+               if (!response)
+                       return SR_ERR;
+
+       /*
+        * The response to a '*IDN?' is specified by the SCPI spec. It contains
+        * a comma-separated list containing the manufacturer name, instrument
+        * model, serial number of the instrument and the firmware version.
+        */
+       tokens = g_strsplit(response, ",", 0);
+
+       for (num_tokens = 0; tokens[num_tokens] != NULL; num_tokens++);
+
+       if (num_tokens != 4) {
+               sr_dbg("IDN response not according to spec: %80.s", response);
+               g_strfreev(tokens);
+               g_free(response);
+               return SR_ERR;
+       }
+       g_free(response);
+
+       hw_info = g_try_malloc(sizeof(struct sr_scpi_hw_info));
+       if (!hw_info) {
+               g_strfreev(tokens);
+               return SR_ERR_MALLOC;
+       }
+
+       hw_info->manufacturer = g_strdup(tokens[0]);
+       hw_info->model = g_strdup(tokens[1]);
+       hw_info->serial_number = g_strdup(tokens[2]);
+       hw_info->firmware_version = g_strdup(tokens[3]);
+
+       g_strfreev(tokens);
+
+       *scpi_response = hw_info;
+
+       return SR_OK;
+}
+
+/**
+ * Free a sr_scpi_hw_info struct.
+ *
+ * @param hw_info Pointer to the struct to free.
+ *
+ * This function is safe to call with a NULL pointer.
+ */
+SR_PRIV void sr_scpi_hw_info_free(struct sr_scpi_hw_info *hw_info)
+{
+       if (hw_info) {
+               g_free(hw_info->manufacturer);
+               g_free(hw_info->model);
+               g_free(hw_info->serial_number);
+               g_free(hw_info->firmware_version);
+               g_free(hw_info);
+       }
+}
index 358d555951281a7ea00304f8fafd7f3521ec873d..be0114d68dab81d5ae84955fbf857abab7ccb753 100644 (file)
@@ -238,6 +238,54 @@ SR_PRIV GSList *sr_usb_find(libusb_context *usb_ctx, const char *conn);
 SR_PRIV int sr_usb_open(libusb_context *usb_ctx, struct sr_usb_dev_inst *usb);
 #endif
 
+/*--- hardware/common/scpi.c ------------------------------------------------*/
+
+#ifdef HAVE_LIBSERIALPORT
+
+#define SCPI_CMD_IDN "*IDN?"
+#define SCPI_CMD_OPC "*OPC?"
+
+enum {
+       SCPI_CMD_SET_TRIGGER_SOURCE,
+       SCPI_CMD_SET_TIMEBASE,
+       SCPI_CMD_SET_VERTICAL_DIV,
+       SCPI_CMD_SET_TRIGGER_SLOPE,
+       SCPI_CMD_SET_COUPLING,
+       SCPI_CMD_SET_HORIZ_TRIGGERPOS,
+       SCPI_CMD_GET_ANALOG_CHAN_STATE,
+       SCPI_CMD_GET_DIG_CHAN_STATE,
+       SCPI_CMD_GET_TIMEBASE,
+       SCPI_CMD_GET_VERTICAL_DIV,
+       SCPI_CMD_GET_VERTICAL_OFFSET,
+       SCPI_CMD_GET_TRIGGER_SOURCE,
+       SCPI_CMD_GET_HORIZ_TRIGGERPOS,
+       SCPI_CMD_GET_TRIGGER_SLOPE,
+       SCPI_CMD_GET_COUPLING,
+       SCPI_CMD_SET_ANALOG_CHAN_STATE,
+       SCPI_CMD_SET_DIG_CHAN_STATE,
+       SCPI_CMD_GET_DIG_POD_STATE,
+       SCPI_CMD_SET_DIG_POD_STATE,
+       SCPI_CMD_GET_ANALOG_DATA,
+       SCPI_CMD_GET_DIG_DATA,
+};
+
+struct sr_scpi_hw_info {
+       char *manufacturer;
+       char *model;
+       char *serial_number;
+       char *firmware_version;
+};
+
+SR_PRIV int sr_scpi_send(struct sr_serial_dev_inst *serial,
+                        const char *command);
+SR_PRIV int sr_scpi_get_string(struct sr_serial_dev_inst *serial,
+                              const char *command, char **scpi_response);
+SR_PRIV int sr_scpi_get_hw_id(struct sr_serial_dev_inst *serial,
+                             struct sr_scpi_hw_info **scpi_reponse);
+SR_PRIV void sr_scpi_hw_info_free(struct sr_scpi_hw_info *hw_info);
+
+#endif
+
 /*--- hardware/common/dmm/es51922.c -----------------------------------------*/
 
 #define ES51922_PACKET_SIZE 14