@ riad1986 you should now research CDC, and you can find examples (although old) on codeshare. Since you have an EMX DevSys, you can use the COM2 serial port, and a RS232-to-USB connection if you wish. Alternatively you can opt to move to debug on COM2 and use the USB connection on your device (but without a RS232-to-USB cable, you don’t get debugging output). Or the best option in my view is to buy some cheap CP2102 TTL to USB modules on ebay like http://www.ebay.com.au/itm/New-1pcs-USB-2-0-to-TTL-5pin-Serial-Converter-UART-Module-CP2102-STC-5pin-cables-/400524497015 and connect that to the COM3 header and use that for your CDC connection
thank you very much for your help
I try
and thank you very much for all