I2S has me confused

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jkeny

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Is I2S simply a method for signal delivery keeping the clock signals seperate from the data signals by using 4 seperate wires?

It specifies nothing about the data format?

Can somebody help me then with trying to take the I2S output from a PCM2706 DAC to a SAXR57 Digital amp?

The relevant page from the PCM2706 datasheet is attached
 

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jkeny

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The relevant page from the AK4114 IC datasheet attached. This is the first place I think I can splice the I2S signal into but the chip is hardwired to mode 0. Am I right in thinking that mode 7 is the only one that would work for what I want?
 

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jkeny

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Thanks rfbrw,

I have further issues - I've connected a PCM2706 I2S output into a Panasonic digital amp SAXR57 where the A/D converter (PCM1804) would normally output I2S - all I get is loud white noise!

I've lifted the 4 I2S output pins of the PCM1804 chip & connected my I2S signal to the lines MCLK, LRCK,BCLK, DATA.

I measured DC on the I2S pins coming from the PCM2706, as follows:
Dout (data) about 20mV
BCK 1.5V DC
LRCK 1.5V DC
SCK 1.5V DC

Is this correct? Any suggestions?
 
R

rfbrw

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Joined 2001
You really need a 'scope to look at the signals but assuming they are present you need SYSCK from the PCM2706 not to be in contention with any clock signal sent to the PCM1804. Looking at datasheets, for the PCM1804 SCKI is an input whereas SYSCK is an output on the PCM2706.
 
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jkeny

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Joined 2007
Aha - because I wanted to avail of the volume control in the amp which is done digitally in the next IC along - Yamaha Ys944 DSP.

I suppose I should look at feeding I2S into the DSP but lifting the pins of one of the three PCM1804 A/D converters was the easiest & least disruptive way of getting I2S in. It would only knock out 2 of the 6 channel analog-in function of the amp which I'm not as yet using!
 
hifimaker

hifimaker

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hifimaker.com
I had the same problem of hearing only white noise the first time setting up a receiver. It's a configuration problem with the AK4114. If the timing, bit format (Left, right, etc.), etc is incorrect, then you can get either no output or white noise.

Make sure you know the bit format of your source and the sample rate, when configuring the AK4114.

-David
 
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jkeny

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Joined 2007
Problem is I'm tapping into a line to the Ak4114 which was normally connected to PCM1804 A/D. I've no control over the settings of AK4114 - it's already set via I2C commands from a microproccesor.

I assumed this set it to slave but I'm presuming now it set it to master & I've no way of changing this, so I'm stumped as the PCM2706 also wants to be master!
 
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