Might and Magic: Secret of the Inner Sanctum: Music

Note: These may work with other Masaharu Iwata / Pixel games e.g. Conquest of the Crystal Palace.

Notes

00 = Silence
01 = C
02 = C#
03 = D
04 = D#
05 = E
06 = F
07 = F#
08 = G
09 = G#
0A = A
0B = A#
0C = B
0D+ = Repeat + 1 Key
1X XX -1 Key Wave
XX = Timer
2X XX Same Key Wave
XX = Timer
3X XX +1 Key Wave
XX = Timer

Header

$01 = Square Frequency
$02-03 = Square 1 Pointer
$04-05 = Square 2 Pointer
$06-07 = Triangle Pointer
$08-09 = Noise Pointer

Music

00-Town
01-Surface of the Ground
02-Battle
03-Main Theme
04-In the Castle 
05-Market
06-Map System
07-Astral World and Soul Maze
08-Dungeon
09-Sheltem's Theme
0A-Quest Completed
0B-Game Over
0C-Open Treasure
0E-Jingle 4

Commands

80 XX Set Instrument
XX = Instrument number
83 XX Set Pitch
XX = Pitch
84 Set Key Higher
85 Set Key Lower 
86 XX Set Note Timer
XX = Timer
88 XX Set Duty
XX = Duty
89 XX YY ZZ ZZ Song Branch
XX = Unknown 
YY = Loop Count
ZZ = Jump if Loop Equal
8A XX XX Jump to
XX = Jump Pointer
8B XX Set Loop Timer
XX = Loop Timer
8C Loop Until 00
8D XX YY ZZ WW Set Frequency Modulation
8E XX Set Note Fade
FF End Song