examples/usb: Add a very simple USBDevice example with host.

Signed-off-by: Damien George <damien@micropython.org>

examples/usb/usb_simple_host_pyusb.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+#
+# Host side of the `usb_simple_device.py` example.  This must be run using standard
+# Python on a PC.  See further instructions in `usb_simple_device.py`.
+
+import sys
+import usb.core
+import usb.util
+
+# VID and PID of the custom USB device.
+VID = 0xF055
+PID = 0x9999
+
+# USB endpoints used by the device.
+EP_OUT = 0x01
+EP_IN = 0x81
+
+
+def main():
+    # Search for the custom USB device by VID/PID.
+    dev = usb.core.find(idVendor=VID, idProduct=PID)
+
+    if dev is None:
+        print("No USB device found")
+        sys.exit(1)
+
+    # Claim the USB device.
+    usb.util.claim_interface(dev, 0)
+
+    # Read the device's strings.
+    for i in range(0x11, 0x17):
+        print(f"str{i}:", usb.util.get_string(dev, i))
+
+    # Test writing to the device.
+    ret = dev.write(EP_OUT, b"01234567", timeout=1000)
+    print(ret)
+
+    # Test reading from the device.
+    print(dev.read(EP_IN, 64))
+
+    # Release the USB device.
+    usb.util.release_interface(dev, 0)
+    usb.util.dispose_resources(dev)
+
+
+if __name__ == "__main__":
+    main()