• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 1144 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CP2114 to PCM1794

Gregory King
Prodigy 20 points
Other Parts Discussed in Thread: PCM1794, PCM1794A, PCM1774

CP2114 to PCM1794.pdf

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

  • 0
    TI__Guru**** 189401 points

    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

  • 0 in reply to Don Dapkus
    Prodigy 20 points

    Thanks for your reply. Yes using the PCM1794A.

    I think its because the PCM1794A cant receive, a 12MHz clock which the CP2114 is outputting on MCLK.

    The PCM1794 needs: System Clock: 128, 192, 256, 384, 512, or 768 fS With Autodetect

    SI Labs does recommend the PCM1774 which can receive this frequency: System Clock: Common-Audio Clock 12/24, 13/26, 13.5/27, 19.2/38.4, 19.68/39.36 MHz 

    Will stick to the PCM2707 I think. Its using a 256 SYSCK.

    Thanks

    Greg