midi

boot.py

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+from typing import type_check_only
+import machine
+import midi
+
+# Devices
+exp = machine.ADC(31) # Expression pedal device on pin 31
+serial = pyb.USB_VCP()
+led = Pin(25, Pin.OUT)
+
+# Expression pedal settings
+exp_min = 0 # Expression pedal minimum value
+exp_max = 65535 #Expression pedal maximum value
+
+# Midi settings
+midi_channel = 1 # Target midi channel to write to
+cc = 68 # Target Control Change number - this is for Behringer X32 Matrix 5
+cc_min = 0 # Minimum desired CC output
+cc_max = 100 # Maximum desired CC output (only want fader to go to unity gain - hence not 127)
+
+# This function translates the expression pedal value to the equivalent CC value
+def translate(exp_val):
+  return (((exp_val - exp_min) * (cc_max - cc_min)) / (exp_max - exp_min)) + cc_min
+
+# Test the translate function:
+# for i in range(65535):
+#   print (translate(i))
+
+usb_midi = midi.Controller(serial, channel=midi_channel)
+exp_value_previous = 0
+
+while True:
+  exp_value_current = exp.read_u16()
+  if exp_value_current != exp_value_previous:
+    led.value(1) # Turn led on
+    cc_val = translate(exp_value_current)
+    usb_midi.control_change(cc, cc_val)
+    led.value(0) # Turn led off
+    exp_value_previous = exp_value_current
+    print(cc_val)