scpi-dmm: Gracefully handle meters that lack OPC command.

[libsigrok.git] / src / hardware / scpi-dmm / api.c

diff --git a/src/hardware/scpi-dmm/api.c b/src/hardware/scpi-dmm/api.c
index 7867ebc2acd48b336e47a6efd9c591a7ec607550..c6753860b866a072443e9221acd04179bd48ebe9 100644 (file)
--- a/src/hardware/scpi-dmm/api.c
+++ b/src/hardware/scpi-dmm/api.c
@@ -168,42 +168,42 @@ SR_PRIV const struct scpi_dmm_model models[] = {
                1, 5, cmdset_agilent, ARRAY_AND_SIZE(mqopts_agilent_34405a),
                scpi_dmm_get_meas_agilent,
                ARRAY_AND_SIZE(devopts_generic),
-               0,
+               0, 0,
        },
        {
                "Agilent", "34410A",
                1, 6, cmdset_hp, ARRAY_AND_SIZE(mqopts_agilent_34405a),
                scpi_dmm_get_meas_agilent,
                ARRAY_AND_SIZE(devopts_generic),
-               0,
+               0, 0,
        },
        {
                "GW", "GDM8251A",
                1, 6, cmdset_gwinstek, ARRAY_AND_SIZE(mqopts_gwinstek_gdm8200a),
                scpi_dmm_get_meas_gwinstek,
                ARRAY_AND_SIZE(devopts_generic),
-               1000 * 2500,
+               1000 * 2500, 0,
        },
        {
                "GW", "GDM8255A",
                1, 6, cmdset_gwinstek, ARRAY_AND_SIZE(mqopts_gwinstek_gdm8200a),
                scpi_dmm_get_meas_gwinstek,
                ARRAY_AND_SIZE(devopts_generic),
-               1000 * 2500,
+               1000 * 2500, 0,
        },
        {
                "GWInstek", "GDM9060",
                1, 6, cmdset_gwinstek_906x, ARRAY_AND_SIZE(mqopts_gwinstek_gdm906x),
                scpi_dmm_get_meas_agilent,
                ARRAY_AND_SIZE(devopts_generic),
-               0,
+               0, 0,
        },
        {
                "GWInstek", "GDM9061",
                1, 6, cmdset_gwinstek_906x, ARRAY_AND_SIZE(mqopts_gwinstek_gdm906x),
                scpi_dmm_get_meas_agilent,
                ARRAY_AND_SIZE(devopts_generic),
-               0,
+               0, 0,
        },
        {
                "HP", "34401A",
@@ -211,14 +211,14 @@ SR_PRIV const struct scpi_dmm_model models[] = {
                scpi_dmm_get_meas_agilent,
                ARRAY_AND_SIZE(devopts_generic),
                /* 34401A: typ. 1020ms for AC readings (default is 1000ms). */
-               1000 * 1500,
+               1000 * 1500, 0,
        },
        {
                "Keysight", "34465A",
                1, 5, cmdset_agilent, ARRAY_AND_SIZE(mqopts_agilent_34405a),
                scpi_dmm_get_meas_agilent,
                ARRAY_AND_SIZE(devopts_generic),
-               0,
+               0, 0,
        },
 };
 
@@ -241,6 +241,25 @@ static const struct scpi_dmm_model *is_compatible(const char *vendor, const char
        return NULL;
 }
 
+/*
+ * Some devices (such as Owon XDM2041) do not support the standard
+ * OPeration Complete? command. This function tests the command with
+ * a short timeout, and returns TRUE if any reply (busy or not) is received.
+ */
+static gboolean probe_opc_support(struct sr_scpi_dev_inst *scpi)
+{
+       gboolean result;
+       GString *response;
+
+       response = g_string_sized_new(128);
+       result = TRUE;
+       if (sr_scpi_get_data(scpi, SCPI_CMD_OPC, &response) != SR_OK)
+               result = FALSE;
+       g_string_free(response, TRUE);
+
+       return result;
+}
+
 static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 {
        struct sr_scpi_hw_info *hw_info;
@@ -253,6 +272,9 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
        gchar *channel_name;
        const char *command;
 
+       if (!probe_opc_support(scpi))
+               scpi->no_opc_command = TRUE;
+
        scpi_dmm_cmd_delay(scpi);
        ret = sr_scpi_get_hw_id(scpi, &hw_info);
        if (ret != SR_OK) {