dma code problem

Altera_Forum · ‎02-11-2005

Hello,

First I tried the DMA code example from the sw datasheet.

Than I used the single line codes.

I see the DMA register working and status on 0x800020 changing.

But somehow the sent data to the memory register 0x800000 does not change.

Any idea? Any good code example?

I did find out if you don't init the DMA the length register update can change the whole DMA registers.

# include <stdio.h># include "sys/alt_dma.h"# include "system.h"# include "altera_avalon_dma_regs.h"# include "altera_avalon_dma.c" // for init function

unsigned int *p = (unsigned int*)(0x400000);

void *pdma = (void*) DMA_0_BASE;

int main(void)

{

//init

IOWR_ALTERA_AVALON_DMA_STATUS(DMA_0_BASE, 0);

IOWR_ALTERA_AVALON_DMA_LENGTH(DMA_0_BASE, 0);

//dma

IOWR_ALTERA_AVALON_DMA_RADDRESS(DMA_0_BASE, (int)p);

IOWR_ALTERA_AVALON_DMA_WADDRESS(DMA_0_BASE, 0x00800000);

IOWR_ALTERA_AVALON_DMA_LENGTH(DMA_0_BASE, 20);

// wcon 1, rcon 0, leen 1, ween 0, Reen 0, I_en 1, go 1,32 bit 100 -> ok

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_0_BASE, 0x029C);

printf ("Transfer successful!\n");

return( 0 );

}

Altera_Forum · ‎02-11-2005

Two suggestions:

1) Clear the DMA control register before doing anything else:

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_0_BASE, 0);

(This ensures that the DMA init code within the HAL won't interfere with your operation).

2) Double-check that the DMA write master is connected to the slave at address 0x00800000.

Altera_Forum · ‎02-14-2005

Check your bus configuration in SOPC.

That caught me once. Everyting was running fine, except the data was not coming through.

It turned out to be a missing bus connection.