FPGA, SoC, And CPLD Boards And Kits
FPGA Evaluation and Development Kits
Announcements
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
5238 Discussions

Noise on DE2 Board (audio issue)

Altera_Forum
Honored Contributor II
860 Views

Hi, from some time i have big problem with noise, I have altera de2 board (NOT 70), I clock XCK clock using 18432000 Khz clock from PLL (actualy 18421053). Everything is good, but i've got noise on about 6 bits, i feed signal from board to AMP and noise is amplificated which is bad for me :) ... Anyway, i looked at ADCDAT compared to ADCLRCK pin on logic analyser and osciloscope, noise is on ADCDAT line.I connected audio in to LEDs for positive part of signal and 5 and half of leds is blinking always. Even when i short circuit both channels of MIC or line in to ground. I thought that it is becouse of 10khz difference betwen proper XCK and these which i feed to it. But it can't be changed, oh and i got information in warnings about : 

altpll:altpll_component|pll" output port clk feeds output pin "AUD_XCK" via non-dedicated routing -- jitter performance depends on switching rate of other design elements. Use PLL dedicated clock outputs to ensure jitter performance  

But i don't have any idea how to connect these clocks via proper way... Maybe it is the couse of noise ?  

My I2C is configured that way : 

when inLeft => daneDoWyslania <= X"3400" & "000" & volIn; when inRight => daneDoWyslania <= X"3402" & "000" & volIn; when outLeft => daneDoWyslania <= X"3404" & "0" & volOut; when outRight => daneDoWyslania <= X"3404" & "0" & volOut; when analog => daneDoWyslania <= X"340815"; when digital => daneDoWyslania <= X"340A06"; when power => daneDoWyslania <= X"340C00"; when format => daneDoWyslania <= X"340E01"; when sampling => daneDoWyslania <= X"341002"; when on => daneDoWyslania <= X"341201"; 

 

 

--EDIT  

I attach screen of logic analyser , upper signal is ADCLRCK, 1 is left chan, 0 is right chan, 48Khz sampling, lower is ADCDAT line .... 

http://dark.art.pl/~kvasir/noise.jpg  

 

--EDIT2 

Aha .... Strange behaviour ... When i stuck my board(plexiglass cover) with finger led's are blinking and from AMP i hear this stucking ... Board works like MICrophone, even when nothing is connected to input of codec ... is it normal ? For me very strange ...  

Any help is appreciated, thank you and i'm waiting for replies...
0 Kudos
1 Reply
Altera_Forum
Honored Contributor II
101 Views

Anybody ? Help ?

Reply