The following opcodes can receive MIDI information:
MIDI information for any instruments: aftouch, chanctrl and polyaft, pchbend.
MIDI information for MIDI-triggered instruments: veloc, midictrl, midichn and notnum. See also Converters.
MIDI Controller input for any instrument: ctrl7, ctrl14 and ctrl21.
MIDI Controller input for MIDI-triggered instruments only: midic7, midic14 and midic21.
MIDI controller value initialization: initc7, initc14, initc21 and ctrlinit.
Generic MIDI input: midiin.
massign can be used to specify the csound instrument to be triggered by a particular MIDI channel. pgmassign can be use to assign a csound instrument to a specific MIDI program.