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In the past I have used a PCM2707 to obtain I2S data then used it in conjunction with a PCM1794, with great results.
Rather like this: users.abo.fi/.../JEDAC
Now I wanted to try a Silicon labs CP2114 which should make the same I2S data. I have a circuit which I am testing, but at the moment all I hear is hissing above very feint audio on the output amplifier to earphones. Most of the circuit is copied from the previous design using the PCM2707, so I know it works, but the only real change is the CP2114 instead.
I suspect the reason I can hear the hissing and suppressed audio is because there are some clock & synchronisation issues, since I am certain that LRCK to LRCK and SDOUT to DATA are connected properly. The connections I am using are (CP2114 to PCM1794):
LRCK to LRCK
SDOUT to DATA
SCK to BCK
MCLK to SCK
but should SCK go to SCK and MCLK to BCK rather than the above.
The CP2114 datasheet mentions using MCLK, LRCK, SCK, and SDOUT for the I2S format where as the PCM1794 mentions only using LRCK, BCK & DATA. In the diagrams on page 18 of the CP2114 datasheet and page 16 of the PCM1794 datasheet.
Help... are my connections incorrect?
Greg
Hi, Greg,
I think your problem is that Si Labs part - you should be using a TI device instead!!! LOL
FWIW, there is an updated PCM1794A - I hope you're using it.
As for your question, you need to verify the I2S clocks are connected correctly between the two ICs. It sounds like there might be a slight mismatch between the two clock settings (sample rate, etc). I suspect your connections are correct, well, maybe not, the PCM1794A has four-wire I2S interface - see pins 4-7 on the PCM1794A:
-d2
