程序代码如下: BYTE strR[1024];
volatile BYTE strW[1024]; static volatile int rx_done = 0;
/*
* Callback function that obtains notification that the data has
* been received.
*/
static void done (void* handle, void* data)
{
rx_done++;
} void InitDMA()
{
DWORD st;
for(int i=0;i<512;i++)
{
strR=i&0xff;
strW=0;
}
int rc;
alt_dma_txchan txchan;
alt_dma_rxchan rxchan;
void* tx_data = (void*) strR; /* pointer to data to send */
void* rx_buffer = (void*) strW; /* pointer to rx buffer */
/* Create the transmit channel */
if ((txchan = alt_dma_txchan_open("/dev/dma")) == NULL)
{
printf ("Failed to open transmit channel\r\n");
exit (1);
}
/* Create the receive channel */
if ((rxchan = alt_dma_rxchan_open("/dev/dma")) == NULL)
{
printf ("Failed to open receive channel\r\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\r\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\r\n", rc);
exit (1);
}
/* wait for transfer to complete */
while (!rx_done);
printf ("Transfer successful!\r\n");
ShowData(strR,512);
TRACE("strWP=%p\r\n",strW);
ShowData((PUINT8)strW,512);
} | 
