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From: goode on 26 Jan 2010 09:22
Dear All,
I have a small problem.
I am trying to play a wave file from my SD card. I am not using FAT i am
just reading raw data from the card.
I want to do this using DMA transfer.

I wrote the following code, but this does not output the wave file from the
DAC.
Does anyone have any idea, what i should do?

Best Regards
Kerem

#include <msp430x26x.h>
#include <hal_hardware_board.h>
#include <mmc.h>
#include <stdio.h>
#include <intrinsics.h>
#include <stdint.h>
//__no_init volatile unsigned long DMA0SZ @ DMA0SZ_;


unsigned long cardSize = 0;
unsigned char status = 1;
unsigned int timeout = 0;
int i = 0;
int k= 0;
int kerem = 0;
int filesize = 0;
int* filePtr = NULL;
int sector = 0;

unsigned char buffer[512];

void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
DCOCTL = CALDCO_16MHZ;
BCSCTL1 = CALBC1_16MHZ;
BCSCTL2 = SELM_0 | DIVS_2;
//P1DIR |= 0x01; // Set P1.0 to output
direction
P1DIR = BIT0 | BIT4; // Set P1.0 to output
direction
P2DIR = BIT0 ;
P5DIR = BIT4 | BIT5;
P1SEL = BIT4;
P2SEL = BIT0;
P5SEL = BIT4 | BIT5;

P6DIR = BIT6 ;
P6SEL = BIT6;

ADC12CTL0 = REFON;

DAC12_0CTL = DAC12SREF_0 | DAC12RES | DAC12LSEL_2 | DAC12IR | DAC12AMP_7
| DAC12CALON;

while (DAC12_0CTL & DAC12CALON != 0){
}
DMACTL0 =DMA0TSEL_5;
DMACTL1 = 0;


DMA0CTL = DMADT_0 | DMADSTINCR_0 | DMASRCINCR_3 | DMADSTBYTE |
DMASRCBYTE;

//Initialisation of the MMC/SD-card
while (status != 0) // if return in not NULL an
error did occur and the
// MMC/SD-card will be
initialized again
{
status = mmcInit();
timeout++;
if (timeout == 150) // Try 50 times till error
{
//printf ("No MMC/SD-card found!! %x\n", status);
break;
}
}

while ((mmcPing() != MMC_SUCCESS)); // Wait till card is inserted

// Read the Card Size from the CSD Register
cardSize = mmcReadCardSize();

mmcReadSector(sector, buffer);

__data16_write_addr((unsigned short) &DMA0SA,(unsigned long) buffer
+44);

// Source block address
__data16_write_addr((unsigned short) &DMA0DA,(unsigned long)
&DAC12_0DAT);


DMA0SZ = 64;

TACCR0 = 1;
TACCR1 = 1;
TACCTL1 = OUTMOD_7;

DMA0CTL = DMA0CTL | DMAEN | DMAIE;
DAC12_0CTL = DAC12_0CTL | DAC12ENC | DAC12IFG ;


TACTL = TASSEL_1 | ID_0 | MC_1 | TACLR;

__enable_interrupt();
for (;;)
{

P1OUT ^= 0x01; // Toggle P1.0 using
exclusive-OR

i = 50000; // Delay
do (i--);
while (i != 0);
}
}
#pragma vector = DMA_VECTOR
__interrupt void DMA_int(void)
{

sector++;

mmcReadSector(sector, buffer);


__data16_write_addr((unsigned short) &DMA0SA,(unsigned long) buffer);
//__data16_write_addr((unsigned short) &DMA0SA,(unsigned long) wave);
// Source block address
__data16_write_addr((unsigned short) &DMA0DA,(unsigned long)
&DAC12_0DAT);


DMA0SZ = 512;
DMA0CTL |= DMAEN | DMAIE;

DAC12_0CTL = DAC12_0CTL | DAC12ENC | DAC12IFG ;


}




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