teensy-audio/examples/PlaySynthMusic/PlaySynthMusic.h

// Table of midi note frequencies * 2
//   They are times 2 for greater accuracy, yet still fits in a word.
//   Generated from Excel by =ROUND(2*440/32*(2^((x-9)/12)),0) for 0<x<128
// The lowest notes might not work, depending on the Arduino clock frequency

#ifdef ORIGINAL_TABLE
const unsigned int tune_frequencies2_PGM[128] =
{
    16,17,18,19,21,22,23,24,26,28,29,31,33,35,37,39,41,
    44,46,49,52,55,58,62,65,69,73,78,82,87,92,98,104,110,
    117,123,131,139,147,156,165,175,185,196,208,220,233,
    247,262,277,294,311,330,349,370,392,415,440,466,494,
    523,554,587,622,659,698,740,784,831,880,932,988,1047,
    1109,1175,1245,1319,1397,1480,1568,1661,1760,1865,1976,
    2093,2217,2349,2489,2637,2794,2960,3136,3322,3520,3729,
    3951,4186,4435,4699,4978,5274,5588,5920,6272,6645,7040,
    7459,7902,8372,8870,9397,9956,10548,11175,11840,12544,
    13290,14080,14917,15804,16744,17740,18795,19912,21096,
    22351,23680,25088
};
#else
// This is for the Teensy Audio library which specifies
// frequencies as floating point. See make_notetab.xlsx
const float tune_frequencies2_PGM[128] =
{
    8.1758,    8.6620,    9.1770,    9.7227,    10.3009,    10.9134,    11.5623,    12.2499,
    12.9783,   13.7500,   14.5676,   15.4339,   16.3516,    17.3239,    18.3540,    19.4454,
    20.6017,   21.8268,   23.1247,   24.4997,   25.9565,    27.5000,    29.1352,    30.8677,
    32.7032,   34.6478,   36.7081,   38.8909,   41.2034,    43.6535,    46.2493,    48.9994,
    51.9131,   55.0000,   58.2705,   61.7354,   65.4064,    69.2957,    73.4162,    77.7817,
    82.4069,   87.3071,   92.4986,   97.9989,   103.8262,   110.0000,   116.5409,   123.4708,
    130.8128,  138.5913,  146.8324,  155.5635,  164.8138,   174.6141,   184.9972,   195.9977,
    207.6523,  220.0000,  233.0819,  246.9417,  261.6256,   277.1826,   293.6648,   311.1270,
    329.6276,  349.2282,  369.9944,  391.9954,  415.3047,   440.0000,   466.1638,   493.8833,
    523.2511,  554.3653,  587.3295,  622.2540,  659.2551,   698.4565,   739.9888,   783.9909,
    830.6094,  880.0000,  932.3275,  987.7666,  1046.5023,  1108.7305,  1174.6591,  1244.5079,
    1318.5102, 1396.9129, 1479.9777, 1567.9817, 1661.2188,  1760.0000,  1864.6550,  1975.5332,
    2093.0045, 2217.4610, 2349.3181, 2489.0159, 2637.0205,  2793.8259,  2959.9554,  3135.9635,
    3322.4376, 3520.0000, 3729.3101, 3951.0664, 4186.0090,  4434.9221,  4698.6363,  4978.0317,
    5274.0409, 5587.6517, 5919.9108, 6271.9270, 6644.8752,  7040.0000,  7458.6202,  7902.1328,
    8372.0181, 8869.8442, 9397.2726, 9956.0635, 10548.0818, 11175.3034, 11839.8215, 12543.8540
};
#endif

#define CMD_PLAYNOTE	0x90	/* play a note: low nibble is generator #, note is next byte */
#define CMD_STOPNOTE	0x80	/* stop a note: low nibble is generator # */
#define CMD_RESTART	0xe0	/* restart the score from the beginning */
#define CMD_STOP	0xf0	/* stop playing */

// User must supply this score array
extern unsigned char score[];