cyclone III starter kit & DMA / DDR problem

Hi,

I use a cycIII starter kit : DDR 32MB x16 (http://www.altera.com/products/devkits/altera/kit-cyc3-starter.html).

I would like to use dma to rd/wr data to the DDR memory and measure timings with alt_timestamp().

I have modified a bit the file ddr_test.c provided by the ddr tutorial :

http://www.altera.com/literature/hb/external-memory/emi_tut_ddr.pdf

Here is my code to manage DMA :

# define length 512

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_0_BASE, 0x00000000);

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_0_BASE, 0x00000082);

//DMA go bit is set to zero.

IOWR_ALTERA_AVALON_DMA_STATUS(DMA_0_BASE, 0x00000000);

//clearing done bit

IOWR_ALTERA_AVALON_DMA_RADDRESS(DMA_0_BASE,read_DMA_address);

IOWR_ALTERA_AVALON_DMA_WADDRESS(DMA_0_BASE,write_DMA_address);

IOWR_ALTERA_AVALON_DMA_LENGTH(DMA_0_BASE,(length*2));

printf(" Starting DMA engine \n");

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_0_BASE, 0x0000008A);

I attached a capture of my sopc.

Direct read and write to the DDR work, but not DMA accesses :

When I use:

- read_dma_addr=00000000 = onchip_mem base addr, connected to dma read and write ports

- write_dma_addr=03200000 = altmemphy ddr base addr connected to dma read and write ports

even if I invert read and write dma_addr, dma transfert always failed (verification with memcmp()).

If I invert addr, console menu display random characters (see console.jpg).

I don't understand the problem.

thanks for your help.

Sebastien G