The MAX3420 provides a very simple approach to adding a USB interface to a circuit. It uses a SPI bus to connect to your system. It does require a reasonable amount of configuration and control, so you'll need to connect it to some form of microprocessor/microcontroller.
Download : PCB and Circuit in Eagle
related search : Digital Electronic Project, USB Controller (src)
Download : PCB and Circuit in Eagle
related search : Digital Electronic Project, USB Controller (src)