[[Category:Music and sound]][[Category:Electronic Component]]
''Musical Instrument Digital Interface (MIDI)''
The original MIDI protocol was developed in 1983 by Dave Smith and Ikutaro Kakehashi to enable communication between electronic instruments.
== Software Protocol ==
Basically transmits MIDI is a set of commands like key onthat a synthesizer, key offsampler, plus pitch/volume parametersor software interprets to generate sound.The commands are:
Write more{| class="wikitable"|-! Status Byte (Hex) !! Message Type !! Data Bytes !! Description|-| 0x8 || Note Off || 2 || Stops a note; data bytes set the note number (0–127) and release velocity (0–127, often unused).|-| 0x9 || Note On || 2 || Starts a note; data bytes are note number (0–127) and velocity (0–127, loudness; 0 acts as Note Off).|-| 0xA || Polyphonic Key Pressure || 2 || Adjusts pressure on one note; data bytes are note number (0–127) and pressure value (0–127).|-| 0xB || Control Change || 2 || Changes a controller (e.g., volume, pan, modulation); data bytes are controller number (0–127) and value (0–127).|-| 0xC || Program Change || 1 || Switches instrument; data byte is program number (0–127, e.g., piano, guitar).|-| 0xD || Channel Pressure || 1 || Applies pressure to all notes on a channel; data byte is pressure value (0–127).|-| 0xE || Pitch Bend || 2 || Bends pitch; two data bytes form a 14-bit value (0–16383, 8192 = no bend).|-| 0xF || System Messages || Varies || System-wide commands (e.g., sync, start/stop); data bytes vary by message type.|} A MIDI message is typically 1-3 bytes long: *Status Byte: Defines the message type (e.g., Note On) and channel (0-15, displayed as 1-16). Each status byte has a '1' as its most significant bit.*Data Bytes: Provide specifics (e.g., note number, velocity). Each data byte has a '0' as its most significant bit. The 16-channel system lets one controller command multiple devices or voices independently. For example, Channel 1 could trigger a drum kit while Channel 2 plays a bassline. MIDI doesn’t contain audio data. This makes MIDI files tiny compared to audio files—think kilobytes versus megabytes.
== Hardware Protocol ==
* MIDI is one-directional (MIDI OUT implements only TX, no RX, and MIDI IN implements only RX, no TX)
* There are no control signals like CTS/RTS/DSR/DTR used
The standard in MIDI interface was the MPU-401, first introduced as a standalone hardware by Roland in 1984, and then integrated into PC soundcards.
The MPU-401 had 2 modes:
* In UART mode, it acted as any other MIDI interface, passing MIDI data between the computer and external MIDI devices
* In intelligent mode, the PC offloaded the MIDI playback task to the interface, freeing the PC to do other tasks while the music was playing
== Schematic ==
* [[DHCP MIDI Interface]] (DHCP Electronics)
* [[EMR MIDI Interface]] (MIDI) (ElectroMusic Research)
* [[LambdaSpeak]] (III and LS)
* [[Music Machine]] (Sampling/Playback/MIDI) (RAM Electronics)
* [[Silicon Systems MIDI Interface]]
* [[Mini Interface for connection to MK5 MIDI Keyboard]]
* [[DIY MIDI Interface from CPCAI magazine]]
* [[DIY MIDI Interface from CPCinfos magazine]] by Thierry MANGION, port &FAF0 [http://cpcrulez.fr/hardware_montage_8x-interface_MIDI-part_2__CNFO.htm]
* [[Willy|Willy MIDI]] General MIDI Wavetable Synth
* [[RSF3]] Multi-purpose expansion card including MIDI synth. It is EMR MIDI compatible [https://youtu.be/YOjV9AaIVKM Source]
== MIDI software for the CPC ==
* [[EMR Miditrack Performer]] (ElectroMusic Research)
== Presentation in ACU magazine magazines ==
<gallery>
image:MIDI test ACU Feb1989 p2.jpg|[[Amstrad Computer User]] reviews MIDI on CPC (page 2/3)
image:MIDI test ACU Feb1989 p3.jpg|[[Amstrad Computer User]] reviews MIDI on CPC (page 3/3)
image:MIDI CPCAI.jpg|[[CPC Amstrad International]] 2/1987 reviews MIDI on CPC (pages 16-22)
image:MIDI Interface CPCAI.jpg|[[CPC Amstrad International]] 2/1987 published a DIY MIDI interface & software for CPC (pages 24-31)
</gallery>
== Presentation in CPCAI magazine General MIDI ==
<gallery>image:General MIDI CPCAI.jpg|[[CPC Amstrad International]] 2/1987 reviews MIDI on CPC (pages 16-22GM)</gallery>is a standardized specification for electronic musical instruments and synthesizers, introduced in 1991 by the MIDI Manufacturers Association and the Japan MIDI Standards Committee.
== DIY General MIDI Interface from CPCAI ==aimed to ensure consistency across devices by defining a uniform set of 128 instrument sounds (called "patches"), organized in a specific program change order:
<gallery>{| class="wikitable"image:MIDI Interface CPCAI! Piano !! Chromatic Percussion !! Organ !! Guitar !! Bass !! Strings !! Ensemble !! Brass|-| 1.jpgAcoustic Grand Piano || 9. Celesta || 17. Drawbar Organ || 25. Acoustic Guitar (nylon) || 33. Acoustic Bass || 41. Violin || 49. String Ensemble 1 || 57. Trumpet|-|[[CPC Amstrad International]] 2/1987 published a DIY MIDI interface & software for CPC . Bright Acoustic Piano || 10. Glockenspiel || 18. Percussive Organ || 26. Acoustic Guitar (pages 24steel) || 34. Electric Bass (finger) || 42. Viola || 50. String Ensemble 2 || 58. Trombone|-| 3. Electric Grand Piano || 11. Music Box || 19. Rock Organ || 27. Electric Guitar (jazz) || 35. Electric Bass (pick) || 43. Cello || 51. Synth Strings 1 || 59. Tuba|-| 4. Honky-tonk Piano || 12. Vibraphone || 20. Church Organ || 28. Electric Guitar (clean) || 36. Fretless Bass || 44. Contrabass || 52. Synth Strings 2 || 60. Muted Trumpet|-| 5. Electric Piano 1 || 13. Marimba || 21. Reed Organ || 29. Electric Guitar (muted) || 37. Slap Bass 1 || 45. Tremolo Strings || 53. Choir Aahs || 61. French Horn|-| 6. Electric Piano 2 || 14. Xylophone || 22. Accordion || 30. Overdriven Guitar || 38. Slap Bass 2 || 46. Pizzicato Strings || 54. Voice Oohs || 62. Brass Section|-| 7. Harpsichord || 15. Tubular Bells || 23. Harmonica || 31. Distortion Guitar || 39. Synth Bass 1 || 47. Orchestral Harp || 55. Synth Voice || 63. Synth Brass 1|-| 8. Clavi || 16. Dulcimer || 24. Tango Accordion || 32. Guitar Harmonics || 40. Synth Bass 2 || 48. Timpani || 56. Orchestra Hit || 64. Synth Brass 2|-! Reed !! Pipe !! Synth Lead !! Synth !! Synth Effects !! Ethnic !! Percussive !! Sound Effects|-| 65. Soprano Sax || 73. Piccolo || 81. Lead 1 (square)|| 89. Pad 1 (new age) || 97. FX 1 (rain) || 105. Sitar || 113. Tinkle Bell || 121. Guitar Fret Noise</gallery>|-| 66. Alto Sax || 74. Flute || 82. Lead 2 (sawtooth) || 90. Pad 2 (warm) || 98. FX 2 (soundtrack) || 106. Banjo || 114. Agogo || 122. Breath Noise|-| 67. Tenor Sax || 75. Recorder || 83. Lead 3 (calliope) || 91. Pad 3 (polysynth) || 99. FX 3 (crystal) || 107. Shamisen || 115. Steel Drums || 123. Seashore|-| 68. Baritone Sax || 76. Pan Flute || 84. Lead 4 (chiff) || 92. Pad 4 (choir) || 100. FX 4 (atmosphere) || 108. Koto || 116. Woodblock || 124. Bird Tweet|-| 69. Oboe || 77. Blown Bottle || 85. Lead 5 (charang) || 93. Pad 5 (bowed) || 101. FX 5 (brightness) || 109. Kalimba || 117. Taiko Drum || 125. Telephone Ring|-| 70. English Horn || 78. Shakuhachi || 86. Lead 6 (voice) || 94. Pad 6 (metallic) || 102. FX 6 (goblins) || 110. Bagpipe || 118. Melodic Tom || 126. Helicopter|-| 71. Bassoon || 79. Whistle || 87. Lead 7 (fifths) || 95. Pad 7 (halo) || 103. FX 7 (echoes) || 111. Fiddle || 119. Synth Drum || 127. Applause|-| 72. Clarinet || 80. Ocarina || 88. Lead 8 (bass+lead) || 96. Pad 8 (sweep) || 104. FX 8 (sci-fi) || 112. Shanai || 120. Reverse Cymbal || 128. Gunshot|} Note: In the actual MIDI data bytes, the instrument numbers are 0-127 (zero-indexed). But in user interfaces and documentation, these are typically displayed as 1-128 (one-indexed) to be more intuitive for musicians. General MIDI allowed musicians and composers to create music that would sound reasonably similar on any GM-compliant device, solving the patchwork compatibility issues of early MIDI systems.
General MIDI largely superseded the previous Roland MT-32 de-facto standard and quickly became foundational in music production, video game soundtracks, and consumer electronics.
== Weblinks ==
* http://en.wikipedia.org/wiki/MIDI_1.0 - wikipedia on MIDI 1.0
* http://en.wikipedia.org/wiki/Musical_Instrument_Digital_Interface - wikipedia on MIDI in general
* [http://tgv777.free.fr/index.php/fichiers-midi/ MIDI Files] [https://musical-artifacts.com/artifacts?order=most_downloaded&q=midi+soundfont MIDI SoundFonts]
* [https://youtu.be/LFWBqUK4G_Q E1M1 Using 40 Different Soundfonts! Comparison w/ Doom MIDI] by [[Doomkid]]
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