USB Vendor Unique Device example.

This example project use the EFM32 USB Device protocol stack
and implements an USB Vendor Unique Device.

The example will toggle User LED's 0-4 when receiving vendor unique class
setup commands.

This example is intended to be used together with the "libusb" device driver,
and host application EFM32-LedApp.exe (a Windows application).

The first time the USB device is connected to the host, you must tell the host
OS to install the "libusb" device driver.

On Windows, you can follow this procedure:
Insert the device, and manually direct Windows to look for drivers in the
directory where you have your copy of the "EFM32_Vendor_Unique_Device.inf" file.
This can be done with the new device "Wizard" which might pop up after device
insertion, or you can open "Device Manager", left click on the new device and
select "Update Driver Software...".

Some versions of Windows wont allow you to install unsigned drivers. If you
suspect this, reboot the PC into "Disable Driver Signature Enforcement" mode.
Win7:
Repeatedly push F8 during boot until the boot menu appears.
Select the "Disable Driver Signature Enforcement" option.
Win10:
Start Menu->Power button->Hold Shift key down and select Restart.
When computer has restarted into the options menu, select:
Troubleshoot->Advanced Option->Startup Settings->Restart->Disable driver signature enforcement
You should now be able to install an unsigned driver.

After libusb is installed, start EFM32-LedApp.exe.

This example will output some info on the DK serial port (115.200 8N1).

Board:  Silicon Labs EFM32LG-DK3650 Development Kit
Device: EFM32LG990F256
