Problems with Delay-based Audio Effects based on spraaa5

Dear Mr. He,

currently I'm working with C672x and audio codec AIC23B. I use your example of "How to Create Delay-based Audio Effects on a TMS320C6727 DSP" in spraaa5.zip.

The codec runs with 12 MHz from CPU clock (external quarz oscillator) and is connected to McASP1. The codec input get a audio signal from CD player and the headphone output is connected to a headphine. I added a control file to init the codec with I2C (CSL library) - this works perfectly. I changed some initial parameters in "main.c" to work with this codec and I hear some audible sound from CD player over codec, but very noisy...

The McASP1 clocks the codec with 12 MHz and 32 bits at I2S format. I used a logic analyzer to analyze the I2S signals ACLK, FSX, FSR, AXR0 and AXR2.
I use internal DSP clock; he codec is the slave device. Next I change the lines 814 in "main.c" to "0" to get 12 MHz BSCLK:

  MCASP1HwCfg.rx.clk.clkSetupClk |= 0;   
  MCASP1HwCfg.tx.clk.clkSetupClk |= 0;


My aim is (at now) to loop back the incomming audio streem to the codec. So in "app.h" I set the currInBuf[i] = currOutBuf[i] . But the sound quality is very noisy and not normal :-(

I tested following: I set the DSP signal pin AXR2 from "output" to "input" (its the DAC signal line) and make a hardware short from digital output of the codec to it's digital input. BitClk and FrameSync are generated by DSP. So I can hear perfect audio - a sign that the McASP engine seems to work.

What in the code I should change to get a 32bit loopback on DSP side?

Please help me with this question.

Thank you very much,
Michael.