Using the RS232 Port on the XST-3.0 Board

• USING THE RS232 PORT ON THE XST-3.0 BOARD
• DESIGN FILES
• USING THE DESIGN EXAMPLE
• ENVIRONMENT
• SOURCE FILES
• AUTHOR
• COPYRIGHT AND LICENSE
• HISTORY

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USING THE RS232 PORT ON THE XST-3.0 BOARD

This is a simple design example that echoes characters received through the RS232 port of the XST-3.0 Board back to the sending terminal.

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DESIGN FILES

• miniuart.vhd, Rxunit.vhd, Txunit.vhd, utils.vhd
These are the design files for a UART that is used to send and receive eight-bit data through the DB9 connector on the XST-3.0 Board. Some small changes were made to these design files, but I can't quite remember what they were. The original files are stored in the

MiniUART.tar.gz

archive if you want to check.

• RS232.vhd
This is the VHDL file that describes a simple state machine that accepts characters received by the UART module and then transmits them back through the UART to the terminal that sent them.

• RS232.ucf
These are the constraints which assign the I/O signals of the RS232 module to the appropriate pins of the FPGA on the XSA-3S1000 + XST-3.0 combination.

• RS232.bit
This is a compiled bitstream for the design that can be downloaded into the XSA-3S1000 + XST-3.0 combination.

• RS232-200.ucf
This is an alternate set of pin assignments to be used if the design is recompiled for an XSA-200 + XST-3.0 combination.

• RS232.npl
Open this project file with WebPACK if you need to recompile the design.

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USING THE DESIGN EXAMPLE

• Step 1:
Set jumper J9 on the XSA-3S1000 Board to XS.

• Step 2:
Download the default parallel port interface into the XSA-3S1000 (

\XSTOOLS\XSA\3S1000\dwnldpar.svf

) if it is not already present. (Running GXSTEST will do this automatically.)

• Step 3:
Connect a straight-thru serial cable between the PC and the female DB9 connector of the XST-3.0 Board. On the XST-3.0 Board near the DB9 connector, make sure the shunts are arranged to connect the following pins on header J7: 1-3, 2-4, 5-7, 6-8.

• Step 4:
On the PC, open a Hyperterminal window with the following settings:

       Bits per second:  9600
        Data bits:           8
        Parity:           None
        Stop bits:           1
        Flow control:     None

• Step 5:

Download the RS232.bitfile to the XSA Board.

• Step 6:

Start typing within the Hyperterminal window. The typed characters will be echoed back and displayed in the window.

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ENVIRONMENT

This example design was developed using the following version of software:

      Xilinx WebPACK       : 6.3.03i

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SOURCE FILES

You can download the source files for this example design from the XESS website at /projects/xst3_RS232.zip .

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AUTHOR

Dave Vanden Bout, X Engineering Software Systems Corp.

Send bug reports to bugs@xess.com.

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COPYRIGHT AND LICENSE

Copyright 2006 by X Engineering Software Systems Corporation.

This application can be freely distributed and modified as long as you do not remove the attributions to the author or his employer.

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HISTORY

01/28/2006 - Initial release.