Question about Audio port

[Altera_Forum]

Hi altera forum. 

Could i ask you about Audio port operation?  ---------------------------------------------------------------------------------# include "address_map_nios2.h"# include "stdlib.h"# include "stdio.h"  # define BUF_SIZE 500000  # define AUDIO_SUBSYSTEM_AUDIO_BASE 0xFF203040;   volatile int * audio_ptr = (int *) AUDIO_SUBSYSTEM_AUDIO_BASE; // audio port address   int fifospace = 0; int buffer_index=0; int left_buffer[BUF_SIZE]; int right_buffer[BUF_SIZE];   int main(void) {  volatile int *audio_ptr = (int *) AUDIO_SUBSYSTEM_AUDIO_BASE; // audio port address  *audio_ptr = 0x03;  int wi=0;  FILE * fpi1 = fopen("01_explosion.raw", "rb"); // get file at project file    while(1){  wi = ((*audio_ptr)&0x200)>>9; // WI    fread((void*)left_buffer,172000,sizeof(float),fpi1); // read file and store to left_buf, file size 172KB    if(wi==1)  {   buffer_index=0;   while(buffer_index < BUF_SIZE)  {  *(audio_ptr + 3) = left_buffer[buffer_index];  *(audio_ptr + 2) = left_buffer[buffer_index];  ++buffer_index;    wi=(((*audio_ptr)&0x200)>>9);  if(wi==0) //wait until next sampling  {  while(wi==0){wi=(((*audio_ptr)&0x200)>>9);}  }    }    }  } }  -------------------------------------------------------------- i'm trying to get audio file from project file and to play through the speaker with monitor program. but it is not play correctly, but sounds like radio signaling sound.  my raw file is 32-bit, mono, format=raw, and 48K sampling.  what should i do?