MidiController_example.py

# install "usb-device-midi" using Tools > Manage packages...
import usb.device
from usb.device.midi import MIDIInterface
import time

# global variables
channel = 0
controller = 64
control_val = 0
note = 60
velocity_min = 0
velocity_max = 127

# instantiate the MIDI interface
midi = MIDIInterface()
# set builtin_driver=False if you don't want the MicroPython serial REPL available.
usb.device.get().init(midi, builtin_driver=True)

while not midi.is_open():
    time.sleep_ms(100)

while midi.is_open():
    midi.note_on(channel, note, velocity_max)
    time.sleep(0.5)

    midi.note_off(channel, note, velocity_min)
    time.sleep(1)

    midi.control_change(channel, controller, control_val)
    control_val += 1
    if control_val == 0x7F:
        control_val = 0
    time.sleep(1)

# note_on(channel, note, velocity)        Triggers a note. (e.g., m.note_on(0, 60, 127) plays Middle C at max volume).
# note_off(channel, note, velocity)       Stops a note. (e.g., m.note_off(0, 60, 0)).
# control_change(channel, control, value) Sends CC messages (like your encoder knob uses).
# program_change(channel, program)        Changes the active instrument patch (0–127).
# pitch_bend(channel, value)              Modulates pitch. Note that pitch bend values are usually 14-bit (0 to 16383, centered at 8192)