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Altera_Forum
Honored Contributor I
813 Views

Noise on DE2 Board (audio issue)

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...
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Altera_Forum
Honored Contributor I
54 Views

Anybody ? Help ?

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