A question about the AD50 and PCM samples. | TMS320C54x

Hello all,

I am trying to output wav sample from the dsk c5402 speaker.

i'm using the AD50 APIs in a C program, and i call the codec_cont_play function after filling the ping pong buffers with some PCM values.

those PCM values were taken from a wav file, we made it using microsoft sound recorder and we choose the sampling rate to be 8 Khz

there is another function that i call, it is called codec_sample_rate, and i gave it 8Khz as a parameter,

I didn't find any documentation of the AD50 API, so i couldn't figure out exactly how each function works.

what i know so far is as follows, the codec_cont_play function enables an ISR, which is called continously (i don't know at what rate) whenever the ping pong buffer contains new data.

I'm not sure what the codec_sample_rate function do, but i hope it has something to do with the rate with which the PCM samples are sent to the D/A.

I hope i'm not bothering you, thank you a lot.

this is the c code which do what is described above, and the PCM values are attached to this mail.

#include <wav4.h>

#define BUF_SIZE 17000
#define TABLE_SIZE &nbs p; 8500 &nbs p;

s16 toneBuf[2][BUF_SIZE];
s16 *pBuf[2];

if ((hCod = codec_open(HANDSET_CODEC)) == 0)
{
printf("codec_open() failed\n");
return(ERROR);
}

/* synthesize tone */
genTone(toneBuf[0], BUF_SIZE, BOTH);
genTone(toneBuf[1], BUF_SIZE, BOTH);

if (codec_sample_rate(hCod,SR_8000) == ERROR)
return (ERROR);

if (codec_dac_mode(hCode,DAC_MODE_16BIT) == ERROR)

    return (ERROR);

    if (codec_cont_play(hCod, MODE_INT, toneBuf[0], toneBuf[1], BUF_SIZE, 0, &bufStatus) == ERROR)
    {
/*        printf("Error playing buffer to codec\n"); */
          return (ERROR);
    }

/* wait for first buffer to be done */
    while (*bufStatus);

while(1)
{
  /* fill buffer and setup for next buffer */
        genTone(toneBuf[bufNum], BUF_SIZE, BOTH);

        bufNum ^= 1;

/* wait for buffer to be empty */
while (*bufStatus != bufNum);
}

}

static void genTone(s16 *pBuf, u16 size, u16 ch)
{
u16 i = 0;
s16 temp;

for (i=0; i<100; i++)
{
  /* index = round-off, grab bit 7 through 14, and shift right by 7 */
  temp = wav[ ((sig.offset + 0x0040) & INTEGER_PART) >> 7 ];
      /*temp = wav[i];*/

  if ( (ch == LEFT) || (ch == BOTH) )
   pBuf[i] = 1 * temp;
  else
   pBuf[i] = 0;

  ++i;

  if ( (ch == RIGHT) || (ch == BOTH) )
   pBuf[i] = 1 * temp;
  else
   pBuf[i] = 0;

   sig.offset += 1;
}
}

Attachment (not stored)

Wav4.zip
Type: application/x-zip-compressed

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Discussion Groups | TMS320C54x | A question about the AD50 and PCM samples.

A question about the AD50 and PCM samples. - Mohamed Montasser - Jun 4 12:09:00 2000