Xilinx SP605 manual USB-to-UART Bridge, USB-to-UART Connections

Detailed Description

12. USB-to-UART Bridge

The SP605 contains a Silicon Labs CP2103GM USB-to-UART bridge device (U4) which allows connection to a host computer with a USB cable. The USB cable is supplied in this evaluation kit (Type A end to host computer, Type Mini-B end to SP605 connector J23). Table 1-16details the SP605 J23 pinout.

Xilinx UART IP is expected to be implemented in the FPGA fabric (for instance, Xilinx XPS UART Lite). The FPGA supports the USB-to-UART bridge using four signal pins: Transmit (TX), Receive (RX), Request to Send (RTS), and Clear to Send (CTS).

Silicon Labs provides royalty-free Virtual COM Port (VCP) drivers which permit the CP2103GM USB-to-UART bridge to appear as a COM port to host computer communications application software (for example, HyperTerm or TeraTerm). The VCP device driver must be installed on the host PC prior to establishing communications with the SP605. Refer to the evaluation kit Getting Started Guide for driver installation instructions.

Table 1-16:USB Type B Pin Assignments and Signal Definitions

USB Connector	Signal Name		Description
Pin
1	VBUS	+5V from host system (not used)
2	USB_DATA_N	Bidirectional differential serial data (N-side)
3	USB_DATA_P	Bidirectional differential serial data (P-side)
4	GROUND	Signal ground
Table 1-17:USB-to-UART Connections
U1 FPGA Pin	UART Function	Schematic Net	U30 CP2103GM	UART Function
	in FPGA	Name	Pin	in CP2103GM
F18	RTS, output	USB_1_CTS	22	CTS, input
F19	CTS, input	USB_1_RTS	23	RTS, output
B21	TX, data out	USB_1_RX	24	RXD, data in
H17	RX, data in	USB_1_TX	25	TXD, data out

Notes:

1.The schematic net names correspond with the CP2103GM pin names and functions, and the UART IP in the FPGA must be connected accordingly.

References

Refer to the Silicon Labs website for technical information on the CP2103GM and the VCP drivers.

In addition, see some of the Xilinx UART IP specifications at:

•http://www.xilinx.com/support/documentation/ip_documentation/xps_uartlite.pdf

•http://www.xilinx.com/support/documentation/ip_documentation/xps_uart16550.pdf

SP605 Hardware User Guide www.xilinx.com 33

UG526 (v1.1.1) February 1, 2010