audio pass-through using C6748-LCDK

Hi Shankari,

Thank you for your response. I tested it on my LCDK board and it works.

I am wondering how I can modify this code to process input audio (an FIR filtering for example).

My problem is not to write an FIR filter (I know it is e.g. available in the libraries) but I do not know how manage the different input and output buffers to realize my filter.

Do you know if there are available examples?

Thank you in advance,

Igig

Hi Igig,

have you made any progress on this?  I'm also trying to figure it out.  The main() method in mcaspPlayBk.c has an infinite loop, take a look at the memcpy() call.

Jose

//mcaspPlayBk.c

    /*
    ** Looop forever. if a new buffer is received, the lastFullRxBuf will be
    ** updated in the rx completion ISR. if it is not the lastSentTxBuf,
    ** buffer is to be sent. This has to be mapped to proper paRAM set.
    */
    while(1)
    {
        if(lastFullRxBuf != lastSentTxBuf)
        {  
            /*
            ** Start the transmission from the link paramset. The param set
            ** 1 will be linked to param set at PAR_TX_START. So do not
            ** update paRAM set1.
            */
            parToSend =  PAR_TX_START + (parOffTxToSend % NUM_PAR);
            parOffTxToSend = (parOffTxToSend + 1) % NUM_PAR;
            parToLink  = PAR_TX_START + parOffTxToSend;
 
            lastSentTxBuf = (lastSentTxBuf + 1) % NUM_BUF;

            /* Copy the buffer */
            memcpy((void *)txBufPtr[lastSentTxBuf],
                   (void *)rxBufPtr[lastFullRxBuf],
                   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);
        }