[Docs] mention note number convention (#972)

tttapa · Nov 5, 2023 · 39d1ab5 · 39d1ab5
1 parent ba8812f
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diff --git a/.../1. MIDI Output/2. Buttons & Switches/1. Momentary Push Buttons/NoteButton/NoteButton.ino b/.../1. MIDI Output/2. Buttons & Switches/1. Momentary Push Buttons/NoteButton/NoteButton.ino
@@ -19,6 +19,10 @@
  *   note C4.
  * - When the button on pin 5 is released, a MIDI Note Off message is sent for 
  *   note C4.
+ *
+ * Note numbers use the [Scientific Pitch Notation system](https://en.wikipedia.org/wiki/Scientific_pitch_notation),
+ * where <b>A<sub>4</sub></b> is 440 Hz, and <b>C<sub>-1</sub></b> is 8.1758 Hz.
+ * See @ref MIDI_Notes for a table of MIDI note numbers.
  * 
  * Mapping
  * -------

diff --git a/examples/examples.dox b/examples/examples.dox
@@ -268,6 +268,10 @@
  *   note C4.
  * - When the button on pin 5 is released, a MIDI Note Off message is sent for 
  *   note C4.
+ *
+ * Note numbers use the [Scientific Pitch Notation system](https://en.wikipedia.org/wiki/Scientific_pitch_notation),
+ * where <b>A<sub>4</sub></b> is 440 Hz, and <b>C<sub>-1</sub></b> is 8.1758 Hz.
+ * See @ref MIDI_Notes for a table of MIDI note numbers.
  * 
  * Mapping
  * -------

diff --git a/src/MIDI_Constants/Notes.hpp b/src/MIDI_Constants/Notes.hpp
@@ -11,6 +11,21 @@ BEGIN_CS_NAMESPACE
 /// @{
 
 /// MIDI note names.
+/// Uses the [Scientific Pitch Notation system](https://en.wikipedia.org/wiki/Scientific_pitch_notation),
+/// where <b>A<sub>4</sub></b> is 440 Hz, and <b>C<sub>-1</sub></b> is 8.1758 Hz.
+///
+/// |Octave| C |C♯/D♭| D |D♯/E♭| E | F  |F♯/G♭| G |G♯/A♭| A |A♯/B♭| B  |
+/// |:-----|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|
+/// |-1    |   0|   1|   2|   3|   4|   5|   6|   7|   8|   9|  10|  11|
+/// |0     |  12|  13|  14|  15|  16|  17|  18|  19|  20|  21|  22|  23|
+/// |1     |  24|  25|  26|  27|  28|  29|  30|  31|  32|  33|  34|  35|
+/// |2     |  36|  37|  38|  39|  40|  41|  42|  43|  44|  45|  46|  47|
+/// |3     |  48|  49|  50|  51|  52|  53|  54|  55|  56|  57|  58|  59|
+/// |4     |  60|  61|  62|  63|  64|  65|  66|  67|  68|  69|  70|  71|
+/// |5     |  72|  73|  74|  75|  76|  77|  78|  79|  80|  81|  82|  83|
+/// |6     |  84|  85|  86|  87|  88|  89|  90|  91|  92|  93|  94|  95|
+/// |7     |  96|  97|  98|  99| 100| 101| 102| 103| 104| 105| 106| 107|
+/// |8     | 108| 109| 110| 111| 112| 113| 114| 115| 116| 117| 118| 119|
 namespace MIDI_Notes {
 
 class Note {

diff --git a/src/MIDI_Constants/Notes.py b/src/MIDI_Constants/Notes.py
@@ -0,0 +1,6 @@
+notes = ["C", "C♯/D♭", "D", "D♯/E♭", "E", "F", "F♯/G♭", "G", "G♯/A♭", "A", "A♯/B♭", "B"]
+print("|Octave| C |C♯/D♭| D |D♯/E♭| E | F  |F♯/G♭| G |G♯/A♭| A |A♯/B♭| B  |")
+print(f"|:-----|{'---:|' * 12}")
+for octave in range(-1, 9):
+    notes = [f"{base + 12 * (octave + 1):4}" for base in range(12)]
+    print(f"|{octave:<6}|{'|'.join(notes)}|")
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
@@ -34,6 +34,7 @@ add_executable(tests
     "MIDI_Senders/test-RelativeCCSender.cpp"
     "MIDI_Parsers/tests-MIDI_Parsers.cpp"
     "MIDI_Constants/test-MCU.cpp"
+    "MIDI_Constants/test-Notes.cpp"
     "MIDI_Outputs/test-PBPotentiometer.cpp"
     "MIDI_Outputs/test-NoteButtonMatrix.cpp"
     "MIDI_Outputs/test-NoteButtonLatching.cpp"

diff --git a/test/MIDI_Constants/test-Notes.cpp b/test/MIDI_Constants/test-Notes.cpp
@@ -0,0 +1,11 @@
+#include <MIDI_Constants/Notes.hpp>
+#include <gtest/gtest.h>
+
+TEST(Notes, noteNumbers) {
+    // See https://en.wikipedia.org/wiki/Scientific_pitch_notation
+    // and page 48 of MIDI 1.0 Detailed Specification 4.2
+    EXPECT_EQ(cs::MIDI_Notes::C(-1), 0x00);
+    EXPECT_EQ(cs::MIDI_Notes::C(0), 0x0C);
+    EXPECT_EQ(cs::MIDI_Notes::C(4), 0x3C);
+    EXPECT_EQ(cs::MIDI_Notes::A(4), 0x45); // 440 Hz
+}