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+# USB Development Notes
+
+Devices such as the Arduino Leonardo supports the implementation of almost any USB client device (except high speed devices probably).
+Here are some notes of things I found useful while implementing MIDI-USB.
+
+## Ubuntu
+
+I did all my development on Ubuntu, which has some great tools for USB debugging. Here are the tools I've used:
+
+### lsusb
+
+`lsusb` will show you all the connected USB devices. To see the descriptors and endpoints for each device, get the device ID (manufacturer and 
+product id) with `lsusb`, then use `lsusb -v -d <vid:pid>`. For example, for the Arduino Leonardo, use `lsusb -v -d 2341:8036`.
+
+### Wireshark 
+
+Wireshark is well known for sniffing network packets, but it can also be used for USB. To enable USB monitoring support, run `sudo modprobe usbmon`
+before launching wireshark, and the USB busses will show up as monitorable devices the next time you launch Wireshark. For more details, see 
+[their wiki][1].
+
+## Development process
+
+### Descriptors and endpoints
+
+The first step is to get the descriptors and endpoints as they should be. Try to replicate the descriptors of an existing device, and use lsusb
+to compare it with yours. If you don't have another device of the same USB type, you may find some lsusb output for a similar device on the internet.
+
+### The send and receive implementations
+
+Try to work off an existing implementation, such as the CDC or HID implementations by Arduino. Here Wireshark helps a lot for debugging.
+Note that data is only sent to the PC if an application is connected. This means that for Serial or MIDI debugging, you need
+to connect an application to the device first before you'll be able to see any data in Wireshark.
+
+### Reset
+
+When developing USB drivers, it is easy get the device to not respond at all, including for code upload. In this case, preset the reset button
+on the board immediately after pressing upload in the Arduino IDE.
+
+## MIDI-specific
+
+`amidi` is useful to display raw MIDI messages coming from the device.
+
+`aplaymidi` is useful to send MIDI data (typically midi files) to the device.
+
+`aconnect` can be used to connect MIDI endpoints together, for example to connect the device to fsynth.
+
+
+ [1]: http://wiki.wireshark.org/CaptureSetup/USB
+
+