About DMA problem..please help me

why the while(!txrx_done); loop never complete? pls help...

Hy everyone ..

testing ssram & sdram : dma operation 
content of ssram_0:before DMA operation 
0: 0 
1: 1 
2: 2 
3: 3 
4: 4 
5: 5 
6: 6 
7: 7 
8: 8 
9: 9 
10: a 
11: b 
12: c 
13: d 
14: e 
15: f 
content of sdram_1:before DMA operation 
0: 0 
1: 0 
2: 0 
3: 0 
4: 0 
5: 0 
6: 0 
7: 0 
8: 0 
9: 0 
10: 0 
11: 0 
12: 0 
13: 0 
14: 0 
15: 0 

while(!txrx_done);

0: 33
1: 33
2: 33
3: 33
4: 33
5: 33
6: 33
7: 33
8: 33
9: 33
10: 33
11: 33
12: 33
13: 33
14: 33 
15: 33

besides , I changed the code to :

    /* Post the transmit request */
    if ((tc = alt_dma_txchan_send (txchan,
            tx_data,
            0x10,
            NULL,
            NULL)) < 0)
    {
        printf ("Failed to post transmit request, reason = %i\n", tc);
        exit (1);
    }
   else
    {
        printf ("Succeed to post transmit request when tc = %i\n",tc);
        //exit (1);
    }
    
    /* Post the receive request */
    if ((rc = alt_dma_rxchan_prepare (rxchan,
            rx_buffer,
            0x10,
            txrxDone,
            NULL)) < 0)
    {
        printf ("Failed to post read request, reason = %i\n", rc);
        exit (1);
    }
   else
    {
        printf ("Succeed to post read request when rc = %i\n",rc);
        printf ("txrx_done = %d",txrx_done);
    }

How about your txrxDone function?

And don't forget to flush/bypass the data cache where appropriate.

    void* tx_data = (void*)SSRAM_BASE; /* pointer to data to send */
    void* rx_buffer = (void*)SDRAM_1_BASE; /* pointer to rx buffer */

    if (txrx_done == 1)
    {
    printf ("Transfer Function Done!\n");
    /* Post the receive request */
    if ((rc = alt_dma_rxchan_prepare (rxchan,
            rx_buffer,
            0x10,
            rx_done,
            NULL)) < 0)
    {
        printf ("Failed to post read request, reason = %i\n", rc);
        exit (1);
    }
   else
    {
        printf ("Succeed to post read request when rc = %i\n",rc);
        printf ("txrx_done = %d\n",txrx_done);
        //printf ("done = %d",done);
    }

//callback function when DMA transfer done
static void tx_done(void * handle, void * data)
{
    txrx_done = 1;
}

TO_BE_DONE

The problem with the if is that if it is executed before the DMA transfer ends, then you will exit your main function without displaying anything. That's why the original code had a while(). Besides I don't think it's a good idea to wait for the end of the tx operation before setting the tx channel. I don't know how the HAL driver is written, but there is probably nothing happening in the DMA until both the transmit and receive channels have been configured.

Thank you for your reply Daixiwen:o,

No SignalTap can be used with older versions of Quartus and SOPC builder without any problems.