I 2 C Bus - Xilinx VC709 User Manual

Silicon Labs provides royalty-free Virtual COM Port (VCP) drivers for the host computer.
These drivers permit the CP2103GM USB-to-UART bridge to appear as a COM port to
communications application software (for example, TeraTerm or HyperTerm) that runs on
the host computer. The VCP device drivers must be installed on the host PC prior to
establishing communications with the VC709 board.
The USB Connector pin assignments and signal definitions between J17 and U44 are listed
in
Table 1-15: USB Connector J17 Pin Assignments and Signal Definitions
USB Connector (J17)
Pin Name
1 VBUS USB_UART_VBUS
2 D_N USB_D_N
3 D_P USB_D_P
4 GND USB_UART_GND
Table 1-16
Table 1-16: FPGA to UART Connections
Refer to the Silicon Labs website for technical information on the CP2103GM and the VCP
drivers (Silicon Labs: www.silabs.com).
2
I C Bus
[Figure
The VC709 board implements a single I
IIC_SDA_SCL, pin AT35), which is routed through a TI Semiconductor PCA9548A 1-to-8
channel I
The bus switch I
to select the desired downstream device.
The four SFP+ connectors SFP1 (P3), SFP2 (P2), SFP3 (P4), and SFP4 (P5) are addressed
through a secondary PCA9546A 1-to-4 channel I
bus topology is shown in
VC709 Evaluation Board
UG887 (v1.0) February 4, 2013
Table 1-15.
Net Name
+5V VBUS powered
Bidirectional differential serial data (N-side)
Bidirectional differential serial data (P-side)
Signal ground
shows the USB connections between the FPGA and the UART.
FPGA (U1)
Pin UART Function
AR34 RTS, output
AT32 CTS, input
AU36 TX, data out
AU33 RX, data in
1-2, callout 14, 15]
2
C bus switch (U52). The bus switch can operate at speeds up to 400 kHz.
2
C address is 0x74 (0b01110100) and must be addressed and configured
Figure
www.xilinx.com
Description
Net Name
USB_UART_CTS
USB_UART_RTS
USB_UART_RX
USB_UART_TX
2
C port on the FPGA (IIC_SDA_MAIN, pin AU32;
2
C bus switch (U14). The VC709 board I
1-16.
Feature Descriptions
CP2103GM (U44)
Pin Name
7 REGIN
8 VBUS
4 D –
3 D +
2 GND1
29 CNR_GND
CP2103GM UART (U44)
Pin UART Function
22 CTS, input
23 RTS, output
24 RXD, data in
25 TXD, data out
2
C
41