X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fhardware%2Fhp-3478a%2Fprotocol.c;h=6767bf0a03b4e7ff8b1b4b260c05a3fbe7abdc16;hb=1c0e1baaaaf0314f49470fb49a4f5e6ddc0ba1a1;hp=de384219b1c52f6a202aad1cbad66b8aadc45877;hpb=04c4a6776fe6abe3dc8138d273b0caf4e72237f8;p=libsigrok.git

diff --git a/src/hardware/hp-3478a/protocol.c b/src/hardware/hp-3478a/protocol.c
index de384219..6767bf0a 100644
--- 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);