Digilent 410-044-10P-KIT - Manual (Page 33)

Spartan-3 Starter Kit Board User Guide www.xilinx.com 33
UG130 (v1.1) May 13, 2005 1-800-255-7778
R
Chapter 7
RS-232 Serial Port
The Spartan-3 Starter Kit board has an RS-232 serial port. The RS-232 transmit and receive
signals appear on the female DB9 connector, labeled J2, indicated as
in Figure 1-2 . The
connector is a DCE-style port and connects to the DB9 DTE-style serial port connector
available on most personal computers and workstations. Use a standard straight-through
serial cable to connect the Spartan-3 Starter Kit board to the PC’s serial port.
Figure 7-1 shows the connection between the FPGA and the DB9 connector, including the
Maxim MAX3232 RS-232 voltage converter, indicated as in Figure 1-2 . The FPGA
supplies serial output data as LVTLL or LVCMOS levels to the Maxim device, which in
turn, converts the logic value to the appropriate RS-232 voltage level. Likewise, the Maxim
6
Figure 7-1: RS-232 Serial Port
Pin 1
Pin 6 Pin 9
Pin 5
DB9 Serial Port Connector
(front view)
UG130_c7_01_072104
R13
T13
TXD
RXD
T14
N10
TXD-A
RXD-A
Spartan-3 FPGA 1
2
3
4
5
6
7
8
9
Maxim MAX3232
RS232 Voltage
Translator
DIN1
ROUT1
DB9
Connector
DOUT1
RIN1
J1 Header
Auxiliary Serial Port
DIN2
ROUT2
DOUT2
RIN2
7
6
1
8
Receiver
Transmitter
FPGA pin number
GND
LD7 LD6 LD5
7