DMA transfer problem

[Altera_Forum]

Hi, i'm working on my design with NiosII , two sdram controller , 3 dma and some other peripheral. 

Now all hardware and software seem working fine, except DMA. The program is working correctly from flash to Dram , where i can write and read on each dram controller without difficulty. I have a lot of problem when i try to use the DMA, i&#39;m using it directly with IOWR functions, i have cecked the contenents of DMA register in assembly and it&#39;s OK. (read and write are 32bit size) When i use the dma i find on destination buffer for example only 24 bytes istead the 4096 requested........, the dram tsu and tco seem correct, in any case i try to reduce the system speed from 100 to 80 and after to 50 MHz, but with same result.  I cechk all topic about the dma in this forum, but i don&#39;t find any idea.   http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/dry.gif http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/dry.gif   any suggestion welcome........

[Altera_Forum]

Hi Roberto, 

 I would use the HAL implementation instead of IOWRs directly, the HAL works fine for DMA. Also, I would, if you have modelsim, do a functional simulation to see what your DMA tranactions are doing.  -Baycool