add simpletest for Feather RP2040 with USB Type A Host

Author: todbot

examples/usb_host_midi_simpletest_rp2040usbfeather.py

@@ -0,0 +1,45 @@
+# SPDX-FileCopyrightText: Copyright (c) 2023 Scott Shawcroft for Adafruit Industries
+#
+# SPDX-License-Identifier: Unlicense
+
+import audiopwmio
+import board
+import synthio
+import adafruit_midi
+import adafruit_usb_host_midi
+import usb.core
+from adafruit_midi.note_on import NoteOn
+from adafruit_midi.note_off import NoteOff
+
+print("Looking for midi device")
+raw_midi = None
+while raw_midi is None:
+    for device in usb.core.find(find_all=True):
+        try:
+            raw_midi = adafruit_usb_host_midi.MIDI(device)
+            print("Found", hex(device.idVendor), hex(device.idProduct))
+        except ValueError:
+            continue
+
+# This setup is for pin D4 on Feather RP2040 with USB Type A Host
+# You must wire this up yourself to an RC filter and headphones or line in of an amp
+audio = audiopwmio.PWMAudioOut(board.D4)
+synth = synthio.Synthesizer(sample_rate=22050)
+audio.play(synth)
+
+midi = adafruit_midi.MIDI(midi_in=raw_midi, in_channel=0)
+
+pressed = {}
+
+while True:
+    msg = midi.receive()
+    if isinstance(msg, NoteOn) and msg.velocity != 0:
+        note = synthio.Note(synthio.midi_to_hz(msg.note))
+        print("noteOn: ", msg.note, "vel:", msg.velocity)
+        synth.press(note)
+        pressed[msg.note] = note
+    elif (isinstance(msg,NoteOff) or (isinstance(msg,NoteOn) and msg.velocity==0)) and msg.note in pressed:
+        print("noteOff:", msg.note, "vel:", msg.velocity)
+        note = pressed[msg.note]
+        synth.release(note)
+        del pressed[msg.note]