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Version 1.09
2.9.10
USB 2.0 UART Device
The USB 2.0 UART device controller (U401) is connected to J400 (USB 2.0 Micro-B connector). It allows
exchanging debug and control commands between the host computer and the FPGA module or FX3.
By default U401 is connected to both, the Mars module connector (Pins 34 and 36) and the FX3
controller (FX3_DQ28..31). Please make sure to drive the signals only from one device.
Using the DIP switch the USB UART can also be routed to pins 153 and 155 (instead of 34 and 36) of
the Mars connector. This is for use with SOC modules. But since these pins are shared with the FX3
FIFO interface this option must only be used when the FX3 FIFO interface is not used.
For more information about the USB 2.0 UART device please refer to the FT232RQ datasheet.
Pin
Signal
Direction Description
22
CBUS0
OUT
RX LED (D401, Yellow)
21
CBUS1
OUT
TX LED (D402, Yellow)
10
CBUS2
Not connected
11
CBUS3
Not connected
9
CBUS4
Not connected
30
FTDI_TXD
OUT
RS232 TXD
2
FTDI_RXD
IN
RS232 RXD
8
FTDI_CTS#
IN
RS232 CTS#
32
FTDI_RTS#
OUT
RS232 RTS#
Table 28: USB 2.0 UART device pin assignment