DE3 THDB-ADA problem

Altera_Forum · ‎06-25-2009

Dear guys,

I am having a trouble with the Terasic DE3 THDB-ADA board.

First I tried to run the demo on the CD. After compilation, when I

programed the device, I got this message: File

G:/TERASIC_ADA/Demostrations/DE3_ADA/150ES/DE3_time_limited.sof contains

one or more time-limited megafunctions that support the OpenCore plus

feature that will not work after the hardware evaluation time expires.

So I tested the D/A with a small VHDL file. I connected the ADA to the

HSTC_D on the DE3 board. I found the pin assignment for the D/A in the

demo file. I tried to output a sin wave. But nothing was

shown even I just sent a constant number to D/A.

I saw a component IOV_A3v3_b3v3_c3v3_d3v3 in the demo, what is it

for?

My VHDL code is attached.

Thanks for helping!

Altera_Forum · ‎06-25-2009

Did you notice that the ADA board has a transformer coupled DA output? It has a lower cut-off frequency of 0.4 MHz and surely can't transmit DC levels. If you apply sine or other generated signals, they should have a sufficient frequency.

Altera_Forum · ‎06-26-2009

No, I didn't know about that. Does that mean that I can't output a sine wave of less than 400kHz?? What about 60Hz.?

Thanks.

Altera_Forum · ‎06-26-2009

60 Hz is attenuated to effectively zero. There is an option to desolder the transformer and place a jumper resistor. Then you get a DC capable single ended DAC outputs.