I2S data handler

main2.c

// This is the I2S data handler - all data exchange related to the I2S transfers
// is done here.
static void data_handler(uint32_t const * p_data_received,
                         uint32_t       * p_data_to_send,
                         uint16_t         number_of_words)
{
    // Non-NULL value in 'p_data_to_send' indicates that the driver needs
    // a new portion of data to send.
    if (p_data_to_send != NULL)
    {
        // do nothing - buffer is updated elsewhere
    }
}