Fix USB demo

Author: Jonas Schievink

examples/usb/.cargo/config

@@ -0,0 +1,63 @@
+[default.probe]
+# USB vendor ID
+# usb_vid = "1337"
+# USB product ID
+# usb_pid = "1337"
+# Serial number
+# serial = "12345678"
+# The protocol to be used for communicating with the target.
+protocol = "Swd"
+# The speed in kHz of the data link to the target.
+# speed = 1337
+
+[default.flashing]
+# Whether or not the target should be flashed.
+enabled = true
+# Whether or not the target should be halted after reset.
+# DEPRECATED, moved to reset section
+halt_afterwards = false
+# Whether or not bytes erased but not rewritten with data from the ELF
+# should be restored with their contents before erasing.
+restore_unwritten_bytes = false
+# The path where an SVG of the assembled flash layout should be written to.
+# flash_layout_output_path = "out.svg"
+
+[default.reset]
+# Whether or not the target should be reset.
+# When flashing is enabled as well, the target will be reset after flashing.
+enabled = true
+# Whether or not the target should be halted after reset.
+halt_afterwards = false
+
+[default.general]
+# The chip name of the chip to be debugged.
+chip = "nRF52840"
+# A list of chip descriptions to be loaded during runtime.
+chip_descriptions = []
+# The default log level to be used. Possible values are one of:
+#   "OFF", "ERROR", "WARN", "INFO", "DEBUG", "TRACE" 
+log_level = "WARN"
+
+[default.rtt]
+# Whether or not an RTTUI should be opened after flashing.
+# This is exclusive and cannot be used with GDB at the moment.
+enabled = true
+# A list of channel associations to be displayed. If left empty, all channels are displayed.
+channels = [
+    # { up = 0, down = 0, name = "name", format = "String" }
+]
+# The duration in ms for which the logger should retry to attach to RTT.
+timeout = 3000
+# Whether timestamps in the RTTUI are enabled
+show_timestamps = true
+# Whether to save rtt history buffer on exit.
+log_enabled = false
+# Where to save rtt history buffer relative to manifest path.
+log_path = "./logs"
+
+[default.gdb]
+# Whether or not a GDB server should be opened after flashing.
+# This is exclusive and cannot be used with RTT at the moment.
+enabled = false
+# The connection string in host:port format wher the GDB server will open a socket.
+# gdb_connection_string

examples/usb/Embed.toml

@@ -1,14 +1,6 @@
-# spi-demo
-SPIM demonstation code.
-Connect a resistor between pin 22 and 23 on the demo board to feed MOSI directly back to MISO
-If all tests pass all four Led (Led1 to Led4) will light up, in case of error only at least one of the Led will remain turned off.
+# USB examples
 
+This demo provides two binaries:
 
-## HW connections
-Pin     Connecton
-P0.24   SPIclk
-P0.23   MOSI
-P0.22   MISO
-
-This is designed for nRF52-DK board:
-https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52-DK
+- `serial`: a USB serial "echo" example.
+- `test_class`: exposes the test device from the `usb-device` crate.