hp-3478a: fix values for digits properties

Unify the hp-3478a driver with the other drivers regarding the use of the
digits properties in the analog payload. This commit adjusts the previously
unclear, but now clarified, use of these properties:

Number of significant digits after the decimal point, if positive. When
negative, exponent with reversed polarity that is necessary to express the
value with all digits without a decimal point.

diff --git a/src/hardware/hp-3478a/api.c b/src/hardware/hp-3478a/api.c
index 1979c52928d78dfcae41c989668e1e5571f328fa..19d96ee155f352a0cc2e86b04931df1d7c7a30b0 100644 (file)
--- a/src/hardware/hp-3478a/api.c
+++ b/src/hardware/hp-3478a/api.c
@@ -102,7 +102,7 @@ static const char *digits[] = {
        "3.5", "4.5", "5.5",
 };
 
-/** Mapping between devc->spec_digits and digits string. */
+/** Mapping between devc->digits and digits string. */
 static const char *digits_map[] = {
        "", "", "", "", "3.5", "4.5", "5.5",
 };
@@ -227,7 +227,7 @@ static int config_get(uint32_t key, GVariant **data,
                ret = hp_3478a_get_status_bytes(sdi);
                if (ret != SR_OK)
                        return ret;
-               *data = g_variant_new_string(digits_map[devc->spec_digits]);
+               *data = g_variant_new_string(digits_map[devc->digits]);
                break;
        default:
                return SR_ERR_NA;

diff --git a/src/hardware/hp-3478a/protocol.c b/src/hardware/hp-3478a/protocol.c
index ed8878bec5a25c8560950713b0ba21caf942d740..6e3b2bc1aff8c887ef77ea9c03d86ee6f8ca6a51 100644 (file)
--- a/src/hardware/hp-3478a/protocol.c
+++ b/src/hardware/hp-3478a/protocol.c
@@ -115,11 +115,11 @@ SR_PRIV int hp_3478a_set_digits(const struct sr_dev_inst *sdi, uint8_t digits)
        struct sr_scpi_dev_inst *scpi = sdi->conn;
        struct dev_context *devc = sdi->priv;
 
-       /* No need to send command if we're not changing the range. */
-       if (devc->spec_digits == digits)
+       /* No need to send command if we're not changing the resolution. */
+       if (devc->digits == digits)
                return SR_OK;
 
-       /* digits are based on devc->spec_digits, so we have to substract 1 */
+       /* digits are the total number of digits, so we have to substract 1 */
        ret = sr_scpi_send(scpi, "N%i", digits-1);
        if (ret != SR_OK)
                return ret;
@@ -131,19 +131,19 @@ static int parse_range_vdc(struct dev_context *devc, uint8_t range_byte)
 {
        if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30MV) {
                devc->range_exp = -2;
-               devc->enc_digits = devc->spec_digits - 2;
+               devc->sr_digits = devc->digits + 1;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300MV) {
                devc->range_exp = -1;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_3V) {
                devc->range_exp = 0;
-               devc->enc_digits = devc->spec_digits - 1;
+               devc->sr_digits = devc->digits - 1;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_30V) {
                devc->range_exp = 1;
-               devc->enc_digits = devc->spec_digits - 2;
+               devc->sr_digits = devc->digits - 2;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VDC_300V) {
                devc->range_exp = 2;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits - 3;
        } else
                return SR_ERR_DATA;
 
@@ -154,16 +154,16 @@ static int parse_range_vac(struct dev_context *devc, uint8_t range_byte)
 {
        if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300MV) {
                devc->range_exp = -1;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_3V) {
                devc->range_exp = 0;
-               devc->enc_digits = devc->spec_digits - 1;
+               devc->sr_digits = devc->digits - 1;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_30V) {
                devc->range_exp = 1;
-               devc->enc_digits = devc->spec_digits - 2;
+               devc->sr_digits = devc->digits - 2;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_VAC_300V) {
                devc->range_exp = 2;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits - 3;
        } else
                return SR_ERR_DATA;
 
@@ -174,10 +174,10 @@ static int parse_range_a(struct dev_context *devc, uint8_t range_byte)
 {
        if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_300MA) {
                devc->range_exp = -1;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_A_3A) {
                devc->range_exp = 0;
-               devc->enc_digits = devc->spec_digits - 1;
+               devc->sr_digits = devc->digits - 1;
        } else
                return SR_ERR_DATA;
 
@@ -188,25 +188,25 @@ static int parse_range_ohm(struct dev_context *devc, uint8_t range_byte)
 {
        if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30R) {
                devc->range_exp = 1;
-               devc->enc_digits = devc->spec_digits - 2;
+               devc->sr_digits = devc->digits - 2;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300R) {
                devc->range_exp = 2;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits - 3;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3KR) {
                devc->range_exp = 3;
-               devc->enc_digits = devc->spec_digits - 1;
+               devc->sr_digits = devc->digits - 4;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30KR) {
                devc->range_exp = 4;
-               devc->enc_digits = devc->spec_digits - 2;
+               devc->sr_digits = devc->digits - 5;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_300KR) {
                devc->range_exp = 5;
-               devc->enc_digits = devc->spec_digits - 3;
+               devc->sr_digits = devc->digits - 6;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_3MR) {
                devc->range_exp = 6;
-               devc->enc_digits = devc->spec_digits - 1;
+               devc->sr_digits = devc->digits - 7;
        } else if ((range_byte & SB1_RANGE_BLOCK) == RANGE_OHM_30MR) {
                devc->range_exp = 7;
-               devc->enc_digits = devc->spec_digits - 2;
+               devc->sr_digits = devc->digits - 8;
        } else
                return SR_ERR_DATA;
 
@@ -215,13 +215,13 @@ static int parse_range_ohm(struct dev_context *devc, uint8_t range_byte)
 
 static int parse_function_byte(struct dev_context *devc, uint8_t function_byte)
 {
-       /* Digits / Resolution (spec_digits must be set before range parsing) */
+       /* Digits / Resolution (digits must be set before range parsing) */
        if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_5_5)
-               devc->spec_digits = 6;
+               devc->digits = 6;
        else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_4_5)
-               devc->spec_digits = 5;
+               devc->digits = 5;
        else if ((function_byte & SB1_DIGITS_BLOCK) == DIGITS_3_5)
-               devc->spec_digits = 4;
+               devc->digits = 4;
        else
                return SR_ERR_DATA;
 
@@ -443,7 +443,7 @@ static void acq_send_measurement(struct sr_dev_inst *sdi)
        packet.type = SR_DF_ANALOG;
        packet.payload = &analog;
 
-       sr_analog_init(&analog, &encoding, &meaning, &spec, devc->enc_digits);
+       sr_analog_init(&analog, &encoding, &meaning, &spec, devc->sr_digits);
 
        /* TODO: Implement NAN, depending on counts, range and value. */
        f = devc->measurement;
@@ -452,14 +452,14 @@ static void acq_send_measurement(struct sr_dev_inst *sdi)
 
        encoding.unitsize = sizeof(float);
        encoding.is_float = TRUE;
-       encoding.digits = devc->enc_digits;
+       encoding.digits = devc->sr_digits;
 
        meaning.mq = devc->measurement_mq;
        meaning.mqflags = devc->acquisition_mq_flags;
        meaning.unit = devc->measurement_unit;
        meaning.channels = sdi->channels;
 
-       spec.spec_digits = devc->spec_digits;
+       spec.spec_digits = devc->sr_digits;
 
        sr_session_send(sdi, &packet);
 }

diff --git a/src/hardware/hp-3478a/protocol.h b/src/hardware/hp-3478a/protocol.h
index a6318f92c67f39f91f29ca8f296b84e8832ba8d1..2b394aa5961a00c552dd53acfbdb9ec0d72b5804 100644 (file)
--- a/src/hardware/hp-3478a/protocol.h
+++ b/src/hardware/hp-3478a/protocol.h
@@ -150,8 +150,16 @@ struct dev_context {
        enum sr_mqflag acquisition_mq_flags;
        enum sr_unit measurement_unit;
        int range_exp;
-       uint8_t enc_digits;
-       uint8_t spec_digits;
+       /**
+        * The total number of digits. Rounded up from the resoultion of
+        * the device, so a 5.5 resolution would be 6 digits.
+        */
+       uint8_t digits;
+       /**
+        * The digits used for encoding.digits and spec.spec_digits in
+        * the analog payload.
+        */
+       uint8_t sr_digits;
 
        enum terminal_connector terminal;
        enum trigger_state trigger;