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		Release notes for usb device demo for 72MHz kinetis family
		        Freescale Semiconductor February 2012   
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Demo code runs on the TWR-K20D72M module.

usb_device example emulates a COM port in a Windows HOST using the Comunication Device Class (CDC). The USB is recognized as a standard COM port and creates an echo aplication. This means that everything that goes out from the terminal returns to the terminal 

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Basic Setup
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TWR-K20D72M setup
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J16 VREGIN Selector	5-6	ON

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Demo explanation
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Download the code and run it.
After the micro USB and the PC are connected, the PC will request a driver, point to the Freescale_CDC_Driver_kinetis.inf file located at the utils folder. 

In the Device Manager window a Freescale CDC device will be found after the enumeration process is completed.

After that just start a hyperterminal opening the COM created by the MCU and start typing. All characters comes back immediately

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Note
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This demo does not work for re-enumeration, because a board design issue for TWR-K20D72M, VBUS detection circuit shares the same signal as the OSJTAG serial port, so using VBUS detection circuit to detect when you plug and unplug USB cable cannot be implemented if you also need to see console output.

You can refer to latest sample code for TWR-K20D50M on how to implement this with a GPIO.

