About DMA problem..please help me

hi all

I have try the altera memory test project with Nios II IDE..

but always display "-Testing memory using DMA"... http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/sad.gif

the dma might be already open..

and didn`t display "Memory at 0x%X Okay".......

so...I found the code at nios forum...it should be work

but it always display"wait for transfer to complete"...why?

look like the same problem with memory test !?

I use Quartus II 5.1 SP2 & Nios II IDE 5.1 SP1

the exception address is sram_0 at SOPC Builder

the program memory & .rodata & .rwdata & heap memory & stack memory are sdram_0

and I sure I have connect the DMA read & write master with sdram_0 & avalon tristate bridge in the SOPC builder

this is the code...please help me

thanks....

# include <stdio.h># include "system.h"# include "sys/alt_dma.h"# include "alt_types.h"

/* Create the transmit channel */

static volatile int rx_done = 0;

/* ready handler*/

static void done (void* handle, void* data)

{

rx_done++;

}

int main (int argc, char* argv[], char* envp[])

{

int rc;

alt_u8 Inbuf[1024], Outbuf[1024];

alt_dma_txchan txchan;

alt_dma_rxchan rxchan;

void* tx_data = (void*) &Inbuf[0]; /* pointer to data to send */

void* rx_buffer = (void*) &Outbuf[0]; /* pointer to rx buffer */

if ((txchan = alt_dma_txchan_open("/dev/avalon_dma")) == NULL)

{

printf ("Failed to open transmit channel\n");

exit (1);

}

/* Create the receive channel */

if ((rxchan = alt_dma_rxchan_open("/dev/avalon_dma")) == NULL)

{

printf ("Failed to open receive channel\n");

exit (1);

}

/* Post the transmit request */

if ((rc = alt_dma_txchan_send (txchan,tx_data,1024,NULL,NULL)) < 0)

{

printf ("Failed to post transmit request, reason = %i\n", rc);

exit (1);

}

/* Post the receive request */

if ((rc = alt_dma_rxchan_prepare (rxchan,rx_buffer,1024,done,NULL)) < 0)

{

printf ("Failed to post read request, reason = %i\n", rc);

exit (1);

}

/* wait for transfer to complete */

printf ("wait for transfer to complete\n");

while (!rx_done);

printf("Transfer successful!\n");

return 0;

}