MIDI
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MIDI (Musical Instrument Digital Interface) is a unidirectional serial protocol for connecting musical instruments and computers. Instruments include a multitude of device types, including musical keyboards, synthesizers, sequencers and drum machines.
MIDI control devices are also used for non-musical purposes, such as controller parameters in desktop applications.[1] MIDI input over USB is now supported by the keyboard firmware QMK.
Connector
Classic MIDI uses cables with 5-pin DIN plugs at both ends. MIDI signals go only in one direction on a cable. There are three types of sockets:
- MIDI in — receive signals
- MIDI out — send signals
- MIDI through (or "MIDI thru") — passes on an exact copy of signals coming in through MIDI in.
Computers typically have one MIDI in and one MIDI out. Synthesizers typical have one MIDI in and a MIDI through for connecting devices in series. MIDI is opto-coupled on the receiving side, with grounding only on the sender's side.
MIDI signals have also been passed over other interfaces such as:
- 2.5 mm TRS jacks
- USB: Multiple streams
- Bluetooth Low Energy ("BLE", part of Bluetooth 4.0 and higher)
- Game port: in and out
- IEEE 1394 ("FireWire")
- Ethernet
Protocol
The protocol is serial and unidirectional, consisting of event messages sent in real time as they occur. Standard messages are one to three bytes long.
The original protocol from 1981 runs at a mere 3125 bytes per second, but has no other inherent latency. There can be added latency over USB and BLE.
References
- ↑ Carsten Schlipf — Using a MIDI Controller with Lightroom for a More Efficient Workflow (PetaPixel). Dated 2019-01-26. Retrieved 2024-03-09.
External links
- MIDI on Wikipedia
- www.midi.org — Official web site of the MIDI Association
