Initial Release

usb/device/dev_lowlevel/dev_lowlevel_loopback.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+
+#
+# Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# sudo pip3 install pyusb
+
+import usb.core
+import usb.util
+
+# find our device
+dev = usb.core.find(idVendor=0x0000, idProduct=0x0001)
+
+# was it found?
+if dev is None:
+    raise ValueError('Device not found')
+
+# get an endpoint instance
+cfg = dev.get_active_configuration()
+intf = cfg[(0, 0)]
+
+outep = usb.util.find_descriptor(
+    intf,
+    # match the first OUT endpoint
+    custom_match= \
+        lambda e: \
+            usb.util.endpoint_direction(e.bEndpointAddress) == \
+            usb.util.ENDPOINT_OUT)
+
+inep = usb.util.find_descriptor(
+    intf,
+    # match the first IN endpoint
+    custom_match= \
+        lambda e: \
+            usb.util.endpoint_direction(e.bEndpointAddress) == \
+            usb.util.ENDPOINT_IN)
+
+assert inep is not None
+assert outep is not None
+
+test_string = "Hello World!"
+outep.write(test_string)
+from_device = inep.read(len(test_string))
+
+print("Device Says: {}".format(''.join([chr(x) for x in from_device])))