alt_dma_txchan_send status

Thanx. Truth is, I lifted this code from this forum http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif

This line calls the dma function:

nr_dma_copy_range_to_1_nli("/dev/USB_DMA",(void *)txdata,(void *)usbdata, ByteCount, ALT_DMA_SET_MODE_8 );

Following is the whole routine it gets stuck in the while(!transmitdone) logic like the callback is never called......

/* ************************************************************************* */

/* The following routines is for range-to-1 processing. */

/* ************************************************************************* */

void nr_dma_copy_range_to_1_nli(const char* dma_name,

void* start_addr, //Here,start_addr is the "range"

void* desti_addr, //and desti_addr is the "1"

alt_32 transfer_count,

alt_32 transfer_mode)

{

alt_32 flag;

alt_dma_txchan txchan;

if((txchan=alt_dma_txchan_open(dma_name))==NULL)

{

printf("\n Failed to open transmit channel(range-to-1)!\n");

//exit(1);

}

alt_dma_txchan_ioctl(txchan,transfer_mode,NULL);

alt_dma_txchan_ioctl(txchan,ALT_DMA_TX_STREAM_ON,start_addr);

if((flag=alt_dma_txchan_send(txchan,desti_addr,transfer_count,transmit_done,NULL

))<0)

{

printf("\n Failed to post transmit request(range-to-1)!\n");

//exit(1);

}

while(!transmitdone)

usleep(20);

transmitdone=0;

alt_dma_txchan_ioctl(txchan,ALT_DMA_RX_STREAM_OFF,NULL);

//alt_dma_txchan_close(txchan);

}