FROM:†††††††††††††††††††††††††††††††††† Dr. U. Meyer-Baese

DATE:††††††††††††††††††††††††††††††††††† 9-15-2006

SUBJECT:†††††††††††††††††††††††††††† A/D and D/A Nexys demo

ACKNOLEGMENT:††††††††† This material is based upon work supported by the National Science Foundation under Grant No. DUE-0442600."



Movie text: Welcome to a short demonstration of the D/A and A/D conversion using Digilentís Nexys board. My name is Dr. Meyer-Baese. We use the MatLab/Simulink software and Xilinx System Generator to generate the VHDL code. Then we use the pin file (*.UCF) and Xilinx ISE to generate the bit stream. In the next step we then program the board via parallel cable using Xilinx IMPACT software or with the USB cable using Digilent ADEPT tools.

The test circuit generated a sine and a triangular function using an accumulator and a sine table. The D/A daughter board is connected to the 6-pin port JA and the A/D daughter board is connected to the port JD. The first D/A channel shows a sine wave, while the second D/A channel generates a slow triangular function. This triangular function is used as input for the A/D converter and the output of the A/D conversion is shown on the row of single LEDs. We can change the frequency of the signals using the 8 switches on the Nexys board. The 4 buttons are used as enable for the 7 segment elements. In addition button 0 is used as reset and button 3 is used to display the second input A/D channel. This concludes the demonstration of the A/D and D/A conversion using Digilent Nexys boards

Top level Design






Clock Generation







D/A Interface



A/D Interface