Add config key SR_CONF_DIGITS.

[libsigrok.git] / src / hardware / hp-3478a / protocol.c

diff --git a/src/hardware/hp-3478a/protocol.c b/src/hardware/hp-3478a/protocol.c
index de384219b1c52f6a202aad1cbad66b8aadc45877..6767bf0a03b4e7ff8b1b4b260c05a3fbe7abdc16 100644 (file)
--- a/src/hardware/hp-3478a/protocol.c
+++ b/src/hardware/hp-3478a/protocol.c
@@ -91,81 +91,86 @@ SR_PRIV int hp_3478a_set_mq(const struct sr_dev_inst *sdi, enum sr_mq mq,
 
 static int parse_range_vdc(struct dev_context *devc, uint8_t range_byte)
 {
-       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30MV) {
+       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30MV)
                devc->enc_digits = devc->spec_digits - 2;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300MV) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300MV)
                devc->enc_digits = devc->spec_digits - 3;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_3V) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_3V)
                devc->enc_digits = devc->spec_digits - 1;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30V) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30V)
                devc->enc_digits = devc->spec_digits - 2;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300V) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300V)
                devc->enc_digits = devc->spec_digits - 3;
-       } else {
+       else
                return SR_ERR_DATA;
-       }
 
        return SR_OK;
 }
 
 static int parse_range_vac(struct dev_context *devc, uint8_t range_byte)
 {
-       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300MV) {
+       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300MV)
                devc->enc_digits = devc->spec_digits - 3;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_3V) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_3V)
                devc->enc_digits = devc->spec_digits - 1;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_30V) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_30V)
                devc->enc_digits = devc->spec_digits - 2;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300V) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300V)
                devc->enc_digits = devc->spec_digits - 3;
-       } else {
+       else
                return SR_ERR_DATA;
-       }
 
        return SR_OK;
 }
 
 static int parse_range_a(struct dev_context *devc, uint8_t range_byte)
 {
-       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_300MA) {
+       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_300MA)
                devc->enc_digits = devc->spec_digits - 3;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_3A) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_3A)
                devc->enc_digits = devc->spec_digits - 1;
-       } else {
+       else
                return SR_ERR_DATA;
-       }
 
        return SR_OK;
 }
 
 static int parse_range_ohm(struct dev_context *devc, uint8_t range_byte)
 {
-       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30R) {
+       if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30R)
                devc->enc_digits = devc->spec_digits - 2;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300R) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300R)
                devc->enc_digits = devc->spec_digits - 3;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3KR) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3KR)
                devc->enc_digits = devc->spec_digits - 1;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30KR) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30KR)
                devc->enc_digits = devc->spec_digits - 2;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300KR) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300KR)
                devc->enc_digits = devc->spec_digits - 3;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3MR) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3MR)
                devc->enc_digits = devc->spec_digits - 1;
-       } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30MR) {
+       else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30MR)
                devc->enc_digits = devc->spec_digits - 2;
-       } else {
+       else
                return SR_ERR_DATA;
-       }
 
        return SR_OK;
 }
 
 static int parse_function_byte(struct dev_context *devc, uint8_t function_byte)
 {
-       devc->measurement_mq_flags = 0;
+       /* Digits / Resolution (spec_digits must be set before range parsing) */
+       if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_5_5)
+               devc->spec_digits = 6;
+       else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_4_5)
+               devc->spec_digits = 5;
+       else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_3_5)
+               devc->spec_digits = 4;
+       else
+               return SR_ERR_DATA;
 
        /* Function + Range */
+       devc->measurement_mq_flags = 0;
        if ((function_byte & SB1_FUNCTION_BLOCK) == FUNCTION_VDC) {
                devc->measurement_mq = SR_MQ_VOLTAGE;
                devc->measurement_mq_flags |= SR_MQFLAG_DC;
@@ -201,15 +206,6 @@ static int parse_function_byte(struct dev_context *devc, uint8_t function_byte)
                parse_range_ohm(devc, function_byte);
        }
 
-       /* Digits / Resolution */
-       if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_5_5) {
-               devc->spec_digits = 5;
-       } else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_4_5) {
-               devc->spec_digits = 4;
-       } else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_3_5) {
-               devc->spec_digits = 3;
-       }
-
        return SR_OK;
 }
 
@@ -410,6 +406,7 @@ SR_PRIV int hp_3478a_receive_data(int fd, int revents, void *cb_data)
        struct sr_scpi_dev_inst *scpi;
        struct sr_dev_inst *sdi;
        struct dev_context *devc;
+       char status_register;
 
        (void)fd;
        (void)revents;
@@ -420,18 +417,28 @@ SR_PRIV int hp_3478a_receive_data(int fd, int revents, void *cb_data)
        scpi = sdi->conn;
 
        /*
-        * This is necessary to get the actual range for the encoding digits.
-        * When SPoll is implemmented, this can be done via SPoll.
+        * TODO: Wait for SRQ from the DMM when a new measurement is available.
+        *       For now, we don't wait for a SRQ, but just do a SPoll and
+        *       check the Data Ready bit (0x01).
+        *       This is necessary, because (1) reading a value will block the
+        *       bus until a measurement is available and (2) when switching
+        *       ranges, there could be a timeout.
         */
-       if (hp_3478a_get_status_bytes(sdi) != SR_OK)
+       if (sr_scpi_gpib_spoll(scpi, &status_register) != SR_OK)
+               return FALSE;
+       if (!(((uint8_t)status_register) & 0x01))
+               return TRUE;
+
+       /* Get a reading from the DMM. */
+       if (sr_scpi_get_double(scpi, NULL, &devc->measurement) != SR_OK)
                return FALSE;
 
        /*
-        * TODO: Implement GPIB-SPoll, to get notified by a SRQ when a new
-        *       measurement is available. This is necessary, because when
-        *       switching ranges, there could be a timeout.
+        * This is necessary to get the actual range for the encoding digits.
+        * Must be called after reading the value, because it resets the
+        * status register!
         */
-       if (sr_scpi_get_double(scpi, NULL, &devc->measurement) != SR_OK)
+       if (hp_3478a_get_status_bytes(sdi) != SR_OK)
                return FALSE;
 
        acq_send_measurement(sdi);