Reword and clarify the doc strings for digits in the analog payload

[libsigrok.git] / include / libsigrok / libsigrok.h

diff --git a/include/libsigrok/libsigrok.h b/include/libsigrok/libsigrok.h
index 5300fbe1951e5027a9e587c38b52e1df19590edb..58216c2cdcb525329b505a19c30938ab7f083009 100644 (file)
--- a/include/libsigrok/libsigrok.h
+++ b/include/libsigrok/libsigrok.h
@@ -529,9 +529,22 @@ struct sr_analog_encoding {
        gboolean is_float;
        gboolean is_bigendian;
        /**
-        * Number of significant digits after the decimal point if positive,
-        * or number of non-significant digits before the decimal point if
-        * negative (refers to the value we actually read on the wire).
+        * 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.
+        * Refers to the value we actually read on the wire.
+        *
+        * Examples:
+        *
+        * | Disp. value | Exp. notation       | Exp. not. normalized | digits |
+        * |-------------|---------------------|----------------------|--------|
+        * |  12.34 MOhm |  1.234 * 10^7   Ohm |    1234 * 10^4   Ohm |     -4 |
+        * | 1.2345 MOhm | 1.2345 * 10^6   Ohm |   12345 * 10^2   Ohm |     -2 |
+        * |  123.4 kOhm |  1.234 * 10^5   Ohm |    1234 * 10^2   Ohm |     -2 |
+        * |   1234  Ohm |  1.234 * 10^3   Ohm |    1234 * 10^0   Ohm |      0 |
+        * |  12.34  Ohm |  1.234 * 10^1   Ohm |    1234 * 10^-2  Ohm |      2 |
+        * | 0.0123  Ohm |   1.23 * 10^-2  Ohm |     123 * 10^-4  Ohm |      4 |
+        * |  1.234 pF   |  1.234 * 10^-12 F   |    1234 * 10^-15 F   |     15 |
         */
        int8_t digits;
        gboolean is_digits_decimal;
@@ -548,10 +561,22 @@ struct sr_analog_meaning {
 
 struct sr_analog_spec {
        /**
-        * Number of significant digits after the decimal point if positive,
-        * or number of non-significant digits before the decimal point if
-        * negative (refers to vendor specifications/datasheet or actual
-        * device display).
+        * 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.
+        * Refers to vendor specifications/datasheet or actual device display.
+        *
+        * Examples:
+        *
+        * | On the wire | Exp. notation       | Exp. not. normalized | spec_digits |
+        * |-------------|---------------------|----------------------|-------------|
+        * |  12.34 MOhm |  1.234 * 10^7   Ohm |    1234 * 10^4   Ohm |          -4 |
+        * | 1.2345 MOhm | 1.2345 * 10^6   Ohm |   12345 * 10^2   Ohm |          -2 |
+        * |  123.4 kOhm |  1.234 * 10^5   Ohm |    1234 * 10^2   Ohm |          -2 |
+        * |   1234  Ohm |  1.234 * 10^3   Ohm |    1234 * 10^0   Ohm |           0 |
+        * |  12.34  Ohm |  1.234 * 10^1   Ohm |    1234 * 10^-2  Ohm |           2 |
+        * | 0.0123  Ohm |   1.23 * 10^-2  Ohm |     123 * 10^-4  Ohm |           4 |
+        * |  1.234 pF   |  1.234 * 10^-12 F   |    1234 * 10^-15 F   |          15 |
         */
        int8_t spec_digits;
 };