TMDSLCDK6748: Sine Wave Generator using mcaspPlayBk.c

Part Number:TMDSLCDK6748

Hi,

I'm trying to send a sine wave to the codec using the mcaspPlayBk.c demo code. The generated sine wave looks like this in Code Composer:

It's encoded using 32-bit signed integers and interleaved into the transmit buffer wiht LSB first:

Then I'm sending the data to the transmit buffer to the MCASP controller. 

            //reassemble into 2-channel buffer
            interleave2(tempBufferInt, AUDIO_BUF_SIZE/8, (void *)txBufPtr[lastSentTxBuf]);
/*
            memcpy((void *)txBufPtr[lastSentTxBuf],
                   tempBuffer,
                   AUDIO_BUF_SIZE);
                 */

            /*
            ** Send the buffer by setting the DMA params accordingly.
            ** Here the buffer to send and number of samples are passed as
            ** parameters. This is important, if only transmit section
            ** is to be used.
            */
            BufferTxDMAActivate(lastSentTxBuf, NUM_SAMPLES_PER_AUDIO_BUF,
                                (unsigned short)parToSend,
                                (unsigned short)parToLink);

The problem is the output is scrambled in the transmit buffer txBuf:

I think the samples from the sine wave aren't being sent to the codec correctly. 

thank you,

Scott