http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf USB-UART bridge (attached to connector J6) that allows you to use PC applications to communicate with the board using standard Windows COM port commands. Free USB-COM port drivers, available from www.ftdichip.com under the “Virtual Com Port” or VCP heading, convert USB packets to UART/serial port data. Serial port data is exchanged with the FPGA using a two-wire serial port (TXD/RXD). After the drivers are installed, I/O commands can be used from the PC directed to the COM port to produce serial data traffic on FPGA pins.

The FT2232HL is also used as the controller for the USB-JTAG circuitry, but the USB-UART and USB-JTAG functions behave entirely independent of one another. Programmers interested in using the UART functionality of the FT2232 within their design do not need to worry about the JTAG circuitry interfering with the UART data transfers, and vice-versa. The combination of these two features into a single device allows the Spartan6-Mini to be programmed, communicated with via UART, and powered from a computer attached with a single Micro USB cable. The connections between the FT2232L and the Spartan6 are shown in the below figure.