Using Switches and LEDs on the XST-3.0 Board

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

---

---

USING SWITCHES AND LEDS ON THE XST-3.0 BOARD

This is a simple design example that takes two four-bit numbers entered through the DIP switch of the XST-3.0 Board and displays their sum or difference on the LED digits.

---

DESIGN FILES

• switches_leds.vhd
This is the VHDL file that describes the circuitry which accepts two four-bit numbers, adds or subtracts them and then displays the result on the LED digits.

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

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

• switches_leds-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.

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

---

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:
Download the

switches_leds.bit

file to the XSA Board.

• Step 4:
Set the DIP switches to enter two four-bit numbers, (A3,A2,A1,A0) and (B3,B2,B1,B0), as follows:

                      DIPSW
        1    2    3    4    5    6    7    8
        |    |    |    |    |    |    |    |
       A3   A2   A1   A0   B3   B2   B1   B0

       DIPSW1: A3 (most-significant bit of A)
        DIPSW2: A2
        DIPSW3: A1
        DIPSW4: A0 (least-significant bit of A)
        DIPSW5: B3 (most-significant bit of B)
        DIPSW6: B2
        DIPSW7: B1
        DIPSW8: B0 (least-significant bit of B)

• Step 5:

The sum of A and B will be displayed on LED1 and LED2.

• Step 6:

Press pushbutton PB1 and the difference (A-B) will be displayed on LED1 and LED2.

---

ENVIRONMENT

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

      Xilinx WebPACK       : 6.3.03i

---

SOURCE FILES

You can download the source files for this example design from the XESS website at /projects/xst3_switches_leds.zip .

---

AUTHOR

Dave Vanden Bout, X Engineering Software Systems Corp.

Send bug reports to bugs@xess.com.

---

COPYRIGHT AND LICENSE

Copyright 2006 by X Engineering Software Systems Corporation.

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

---

HISTORY

01/28/2006 - Initial release.