How you use the FPGA to make a USB-Serial (UART) converter?

[hyuna]

Could you possibly explain how you use the FPGA to make a USB-Serial (UART) converter? Have someone known that? Then microcontrollers like the ATtiny can communicate with the computer. I'm sure there are other alternatives like some FTDI chips or whatever that I've read about in forums but this would be a nice DIY method.

[Antti Lukats]

it is possible and there are opensource usb IP available for this, but we strongly recommend not to use the FPGA USB mostly because of USB certification. FPGA IO pin are not fully usb compatible.